Soil Nutrients and Maize Yields Responses to Agroforestry Tree Post-fallows Management in Tanzania

Soil Nutrients and Maize Yields Responses to Agroforestry Tree Post-fallows Management in Tanzania | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Soil Nutrients and Maize Yields Responses to Agroforestry Tree Post-fallows Management in Tanzania Vincent G. Vyamana, Shabani A.O. Chamshama, Samora Macrice Andrew This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-430132/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Agriculture forms a backbone of many countries in sub-Saharan Africa (SSA) thus has the potential to contribute to achieving Sustainable Development Goals (SDGs). However, agriculture in the SSA is characterized by low production due to soil fertility depletion. Use of appropriate low input agricultural technologies may increase production and benefit smallholder farmers through increased productivity in already degraded land. A field experiment was established to assess tree coppice intercropping of Albizia harveyi and Albizia versicolor for soil fertility and maize yield improvements in Morogoro, Tanzania. Tree fallows of A . versicolor aged three years increased significantly soil organic Carbon, Calcium, Magnesium and Potassium. Yields of maize grain, cobs and stover in maize fields intercropped with A . versicolor were significantly higher than those with A . harveyi . Fields with continuous maize cropping had the least yields of grain, cobs and stover. The studied agroforestry tree species are recommended for rotational woodlots and short rotation coppice systems to enhance agricultural productivity for achieving SDGs. Forestry Agriculture Productivity Food security Soil fertility Yield Tanzania Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1 Introduction Agriculture employs about 75% of the workforce and forms a backbone of many developing economies of countries in sub-Sahara Africa (SSA) [ 1 ]. It has therefore the potential to contribute greatly to achieving Sustainable Development Goals (SDGs) particularly poverty eradication, attaining zero hunger and ensuring responsible consumption and production. Adopted unanimously by all UN member states in 2015, SDGs is a collection of global goals set to ensure a better and sustainable future for all citizens by 2030 [ 2 ]. Food production in SSA has increased during the last few decades as a result of expansion of area cultivated into forests and woodlands rather than increased productivity leading to deforestation and land degradation [ 3 ]. Another concern is the fact that population growth estimated at 2.7% in 2017 has already outpaced the increase in food production. Thus, there has been a parallel decline in per capita food production by about 2% per year [ 4 ]. Available records [e.g. 5] show that since the 1970s, Africa has been a net exporter of food but in recent times around $ 35 billion was spent for annual food imports [ 6 ]. More also, currently, two-thirds of African countries are net food importers [ 7 ]. Increasing human population coupled with use of inappropriate agricultural and other land management technologies are among the root causes of the problems of declining per capita food production in the SSA [ 8 ] with negative consequence on SDGs. The escalating population has constrained traditional shifting cultivation that used to be successful in sustaining crop yields. As a result, smallholder farmers have resorted to short fallow or continuous cropping with no external inputs such as fertilizers due to high farm gate prices [ 8 , 9 ]. This has resulted in declining soil fertility and crop yields as well as household incomes due to soil nutrient depletion through repeated crop harvest and soil erosion [ 10 ]. Soil fertility depletion is the major cause of declining per capita food production and the concomitant widespread food shortage, low income and perpetual poverty in Africa [ 6 , 11 ]. This is a consequence of breakdown of traditional shifting cultivation or bush fallow system that was used successfully in the past to replenish and maintain soil fertility [ 12 ]. Shifting cultivation is currently not feasible for most farmers due to dwindling landholdings as a result of increasing population. Farmers are forced to intensify land use by reducing fallow periods to a level that is below the minimum required to maintain soil fertility or practice continuous cropping [ 13 ]. As a result, nutrients are being depleted through nutrient mining via repeated harvesting. In such a situation, the only viable options for replenishment and sustaining soil fertility appear to be application of mineral fertilizers and green manuring [ 14 ] but these are constrained too. Most of the farmers lack the required capital to use adequate and appropriate specification of mineral fertilizers that can counter the effect of short or no fallow on soils [ 10 , 13 ]. While organic manuring could be an option, but the practice is limited by bulky nature of the organic matter (OM) and unavailability [ 13 ]. Agroforestry (AF) practices have been identified as one of appropriate sustainable solutions to the problems of soil fertility depletion, low crop productivity and woodfuel scarcity [ 15 , 16 ] and can reduce wood harvesting pressure on natural forests and woodlands thereby reducing the rate of deforestation. However, despite the potential of AF practices to fix Nitrogen (N), utilization of indigenous tree species in AF has received little attention [ 17 , 18 , 19 ] due to low growth rate and inadequate silvicultural knowledge. Where woodfuel scarcity is acute, crop residues and livestock manure are used as supplementary energy sources [ 20 ], which means little or no OM is available to be returned to the soil in farms. This aggravates the vicious cycle of low agricultural productivity, food shortage, low income and perpetual poverty. Therefore, alternative land use strategies to improve soil fertility and woodfuel supplies are urgently needed to sustain agricultural productivity, conserve the remaining forests and woodlands and ensure achievement of the SDGs. With few exceptions, most AF studies on evaluation and selection of AF trees/shrubs in Tanzania have focused on exotic multipurpose tree/shrub species [ 15 , 21 ]. This is notwithstanding the fact that the indigenous tree/shrub species are more adapted to local environmental conditions and can meet local requirements better than exotics [ 19 ]. In addition, there is increasing realization that indigenous tree species can be more efficient in improving soil fertility and less competitive to the companion crops, especially for soil moisture [ 22 ]. This study was therefore initiated with the overall objective of assessing the potential for utilizing AF tree species ( Albizia harveyi and Albizia versicolor ) and management of their fallows for increasing soil nutrients and yield of maize ( Zea mays ). Maize was used in the study because it is the most widely cultivated cereal of great importance to food security and livelihoods in SSA. 2 Materials And Methods 2.1 Study area The study area (i.e. Maseyu) is located about 50 km east of Morogoro and 150 km west of Dar es Salaam, Tanzania (Fig. 1 ). The area experiences tropical and sub-humid climate [23). It has a bimodal rainfall pattern with annual mean of 900 mm and seasonally distributed on wet (November to May) and dry (June to October) seasons. The mean annual temperature is 24.3°C while the minimum and maximum annual temperatures are 18.6 and 28.8°C, respectively. Because of favourable rainfall and temperature small holder farmers practice rain-fed agriculture where maize ( Zea mays L.), sorghum ( Sorghum bicolour L. Moench) and garden peas ( Pisum sativum L.) are mainly grown. Recently a small portion of local community members have started keeping domestic animals including cattle, sheep and goats. Charcoal production outside agricultural area takes place and contributes significantly to the household income. The area is surrounded by miombo woodland dominated by trees of Julbernardia globiflora (Benth.) Troupin and Combretum spp. On the northern side there is Kitulanghalo Forest Reserve, while on the southern side there is a General Land. Precambrian Usagaran metasedimentory rocks consisting of garnet biotite gneiss dominate the area. Thus, mixed alluvial and colluvial deposits tend to occur in low-lying areas [ 24 ]. The soils of the area are well drained, red, acid–neutral, sandy clay loams with brown friable top soil and are generally nutrient poor. 2.2 Experimental design and establishment A 2 x 2 x 4 x 2 factorial experiment with three replications was established in a randomized arrangement to assess tree coppice intercropping of Albizia harveyi (Ah) and Albizia versicolor (Av) for soil fertility and maize yield improvements (Table 1 ). The experiment was established using four-years plantations of Ah and Av planted separately on the same site. Prior to establishment of the experiment, the site was prepared by clearing all vegetation followed by plowing by a farm tractor and pitting using hand hoe where the pit size was 20 cm x 30 cm x 30 cm. The plantations were kept clean weeded all the time for four years prior to establishment of the cropping system experiment. Plots were rectangular (12 m x 6 m) and plots and blocks were separated by 2.5 and 3 m-unplanted buffer strips, respectively. For each study species, there were a total of 18 such plots of which 14 were used for this study. Table 1 A factorial experimental design for testing the effects of Albizia harveyi and Albizia versicolor and management of their fallows on maize yield and soil nutrients Factor one Factor two Factor three Factor four Two levels of study species Two levels of cropping systems Four levels of tree cutting heights Two levels of coppice thinning Ah = A . harveyi Av = A . versicolor i) IC0 = Continuous maize cropping (control) ii) IC1 = maize intercropped with coppices i) C0 = Trees not cut (tree fallow) ii) C1 = 5 cm (ground level iii) C2 = 30 cm above the ground iv) C3 = 90 cm above the ground i) TH0 = All coppice shoots left (no thinning)- control ii) TH1 = Coppices thinned to leave two coppice shoots per stump Establishment of cropping experiment involved cutting trees at respective heights as per cutting height treatments (Table 1 ). Land was prepared using a hand hoe, and maize seeds of TMV-1 variety were sown for two cropping seasons at a spacing of 30 cm within row and 75 cm between rows giving a population of 44,444 maize plants per ha. Thinning was applied when coppices reached 10 cm height, which was achieved after tree cutting. Subsequent coppice thinning was maintained at the same interval of four months. During the first coppice thinning occasion, the two tallest coppices were left per thinned stump and any coppices that sprouted were subsequently removed. 2.3 Soil fertility, maize growth and yield assessments Just before maize sowing in each season, soil samples were taken from 4 randomly selected points in each intercropped plot at a depth of 0–15 cm using soil auger leaving 1 m border strip on both sides of each plot. These samples were mixed thoroughly and sub-sampled to get a composite sample. The composite soil samples for each plot were transported to the laboratory for soil organic matter (SOM) and soil fertility analysis. All soil sub-samples were oven-dried (70 0 C) to constant weight and sun dried, respectively. The dried samples were then ground to pass through a 1 mm sieve and analysed for Total N (TN), extractable Phosphorus (P), Potassium (K), Magnesium (Mg), Calcium (Ca) and total soil organic Carbon (OC). Extractable P, K, Ca and Mg were determined by simultaneous Inductive Coupled Plasma (ICP) Emission Spectroscopy technique in acid digested samples while Total N was determined by the Kjeldahl procedure. Soil OC was determined by wet calorimetric method [ 25 ]. Maize plants were measured for diameter at 30 cm above ground and height at maturity. Height was measured to the nearest 0.01 m using a graduated pole while basal diameter at 10 cm (D10) was measured to the nearest 0.01 cm using a veneer caliper. At maturity, a total of 20 maize plants in the middle two rows were harvested, stems cut at ground level, weighed fresh and sub-sampled for dry weight determination. Also, maize cobs were harvested, shelled and both shaft and grain weighed fresh and sub-sampled for dry weight determination. Assessment of coppice growth was done at the ages of 6, 12, 18 and 24 months. During each assessment, all surviving coppices were measured for D10 and total height. The tally of height and D10 provided the number of coppice stems per stump. 2.4 Statistical analyses Visual inspection and significance test were used to test for standard parametric statistical assumptions of normality and constant variance of residuals. Visual inspection was done by plotting the residuals against normal scores and predicted values while significance test was executed using Shapiro-Wilks’s test [ 26 ]. Soil Sodium (Na) content, maize plant survival, coppice mortality and stump survival data sets violated the requirements for normality and homoscedasticity. Thus, soil Na content data were square-root transformed; and maize plant survival, coppice mortality, and stump survival data sets were arcsine transformed to correct for deviations from parametric statistical assumptions. However, only non-transformed data are presented for clarity [ 27 ]. Plot means were subjected to Analysis of Variance (ANOVA) using the General Linear Model procedure in Statistical Analysis System (SAS) at 5% level of statistical significance. In the study, block and block-by-treatment interactions were error terms in the model. The ANOVA for maize and soil data tested the effects of two study tree species, three cropping systems, four tree cutting heights and two coppice thinning regimes (a 2 x 3 x 4 x 2 factorial experiment) replicated three times in a RCBD (Table 1 ). For the tree biomass data, the analysis was carried out as a 2 x 2 x 4 x 2 factorial experiment since one level of cropping system did not have tree biomass data. All statistical analyses were done by using SAS version 8 [ 28 ]. 3 Results 3.1 Effects of tree fallow on soils Figure 2 shows results for soil chemical properties from tree fallows of A. harveyi and A. versicolor at three years old just before cutting to establish the experiment to test the effects of A . harveyi and A . versicolor and management of their fallows on maize yield and soil nutrients. At that age of fallow TN of top soil at a depth of 0–20 cm did not differ significantly ( p > 0.05) from that recorded in continuous cropping plots (Fig. 2 -a). The TN in tree fallow ranged from 0.073% in A. harveyi to 0.11% in A . versicolor tree fallows compared to 0.06% in the continuous cropping. Though not statistically significant, the values of TN recorded in tree fallows were higher by 21.7–83.3% compared to continuous cropping plots for A. harveyi and A. versicolor , respectively. This indicates a slightly superior ability of A. versicolor fallow to increase TN as compared to A. harveyi . Organic Carbon was significantly higher ( p < 0.05) under the tree fallows compared to continuous cropping plots. In comparison with continuous cropping plots, amount of OC was higher by 41% and 56% in A. harveyi and A. versicolor tree fallows respectively (Fig. 2 -b). OC ranged from 0.96% in A. harveyi to 1.06% in A. versicolor tree fallows. This was in contrast to 0.68% OC recorded in continuous cropping plots. Despite the lack of statistically significant differences ( p > 0.05), soils under A. versicolor tree fallow contained 67.5% more extractable P compared to the continuous cropping plots (Fig. 2 -c). Effects of tree fallow on ECEC were not significant ( p > 0.05) but it was highest (22.04 Cmol kg − 1 ), intermediate (18.37 Cmol kg − 1 ) and lowest (17.38 Cmol kg − 1 ) under A. versicolor fallow, A. harveyi fallow and continuous cropping plots, respectively (Fig. 2 -d). This corresponds to improvement in ECEC by 5.7–26.8% as a result of tree fallow management. With the exception of Na, A. versicolor tree fallow recorded significantly ( p 0.05) of the factors for all soil chemical properties assessed except for ECEC, which showed significant interaction between tree species and cutting height (Table 2 ). However, there were no significant 3-way interactions among the factors. Table 2 Summary of ANOVA ( p > F ) testing the effects of tree species, coppice cutting height and coppice thinning on soil chemical properties for the second cropping season at Maseyu, Morogoro, Tanzania. Source of variation 1 df TN% OC% P ECEC Ca Mg K Na Block (Blk) 2 2 Tree species (Spp) 1 < 0.0001 < 0.0001 0.8415 0.4756 0.0045 0.0397 0.0562 0.0007 Blk x Spp 2 Cutting height (Cut) 2 0.6768 0.3577 0.6279 0.2948 0.9864 0.2873 0.5441 0.7240 Blk x Cut 4 Spp x Cut 2 0.4209 0.6450 0.1252 0.0238 0.6703 0.8297 0.3415 0.7626 Blk x Spp x Cut 4 Coppice thinning (Coppthin) 1 < .0001 < 0.0001 0.4864 0.0209 0.4013 < .0001 < .0001 < .0001 Blk x Coppthin 2 Spp x Coppthin 1 0.5622 0.0524 0.9537 0.8167 0.0965 0.1853 0.2797 0.2511 Blk x Spp x Cut 4 Cut x Coppthin 2 0.7373 0.3511 0.7135 0.3037 0.9196 0.3378 0.3344 0.4849 Blk x Cut x Coppthin 4 Spp*cut* Coppthin 4 0.7764 0.5586 0.5790 0.3522 0.3099 0.2053 0.3764 0.9521 Blk*Spp*cut* Coppthin 4 - - - - - - - - Residual error 6 - - - - - - - - Corrected total 45 - - - - - - - - 1 df = numerator degree of freedom; 2 No test statistics (i.e., F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning. There were significant effects ( p < 0.05) of tree species, stump cutting height and coppice thinning on the assessed soil chemical properties (Tables 2 and 3 ). Table 3 Effects of tree species, coppice stump cutting height and coppice thinning on soil chemical properties during the second season of intercropping with maize at Maseyu, Morogoro, Tanzania Treatment (Unit)† % % mg kg − 1 g kg − 1 ECEC and bases (Cmole (+) kg − 1 ) TN OC Extrac. P OM ECEC Ca Mg K Na Tree species A. harveyi § 0.07c (0.01) 0.66b (0.02) 5.43a (0.07) 12.41a (0.09) 17.37a (0.08) 2.77b (0.06) 1.15b (0.03) 0.45b (0.01) 0.20b (0.01) A. versicolor 0.38a (0.02) 1.27a (0.03) 4.84a (0.07) 11.31a (0.10) 17.66a (0.08) 4.24a (0.05) 1.46b (0.03) 0.56b (0.02) 0.16c (0.01) Continuous cropping 0.11b (0.24) 0.85b (0.41) 3.13a (0.31) 6.6a (0.44) 10.35a (1.00) 2.64b (0.46) 3.98a (0.69) 1.37a (0.40) 5.09a (0.97) Coppice stump cutting height 0 cm 0.07a (0.01) 0.67a (0.04) 4.67a (0.13) 11.57a (0.15) 18.36a (0.14) 3.78a (0.11) 1.42a (0.04) 0.51a (0.03) 0.18a (0.01) 30 cm 0.53a (0.01) 0.71a (0.06) 5.38a (0.13) 12.27a (0.19) 18.02a (0.14) 3.73a (0.10) 1.16a (0.06) 0.48a (0.04) 0.18a (0.02) 90 cm 0.07a (0.01) 0.80a (0.10) 5.55a (0.08) 13.79a (0.11) 16.70a (0.25) 3.68a (0.12) 1.38a (0.17) 0.56a (0.10) 0.19a (0.24) Tree fallow 0.07a (0.02) 1.7a (0.07) 5.39a (0.30) 9.661a (0.26) 16.43a (0.29) 2.14a (0.19) 3.94a (0.09) 1.38a (0.06) 0.18a (0.03) Continuous cropping 0.07a (0.18) 0.54a (0.31) 2.60a (0.28) 5.198a (0.44) 10.35a (0.75) 2.64a (0.35) 1.22a (0.51) 0.46a (0.30) 5.09a (0.73) Coppice thinning Thinned 0.07c (0.01) 0.72b (0.02) 4.736a (0.09) 12.43a (0.10) 17.42ab (0.10) 3.52a (0.07) 1.31b (0.03) 0.52b (0.02) 0.19b (0.01) Not thinned 0.07c (0.01) 0.73b (0.04) 5.67a (0.09) 12.66a (0.12) 17.97a (0.10) 3.95a (0.06) 1.32b (0.04) 0.50b (0.03) 0.19b (0.01) Tree fallow 0.30a (0.10) 1.08a (0.20) 5.34a (0.15) 8.95a (0.22) 14.67c (0.50) 2.67a (0.23) 2.51a (0.34) 0.90a (0.20) 0.21b (0.48) Continuous maize cropping 0.22b (0.23) 0.95ab (0.38) 2.66a (0.39) 6.27a (0.64) 14.27c (0.45) 2.13a (0.46) 1.33b (0.18) 0.49b (0.15) 2.62a (0.04) †Means for each individual factor are averaged over all other treatments; §Mean of three replicates with standard error in parentheses; within each category means in the same column followed by the same letters are not statistically different at p < 0.05 according to DMRT. Significant effects of tree species on soil chemical properties were detected for TN, OC and soil cations (Ca, Mg and Na). On the other hand, coppice thinning had significant effects on TN, OC, ECEC as well as cations (Mg, K and Na). The overlaps of the effects of these two factors are revealing but it is worth to emphasize that there were no any significant interactions between these two factors. Results showed no significant differences ( p > 0.05) between the two levels of coppice thinning for TN and OC but both recorded similar and significantly lower amounts of TN and OC compared to continuous cropping as well as tree fallows. The same pattern was observed for effects of thinning on amounts of Mg, K and Na. However, the pattern was reversed for ECEC, which was significantly highest ( p < 0.05) in thinned and unthinned coppices compared to tree fallow and maize cropping. The superiority of the tree fallows over both thinned and not thinned coppice plots with regard to soil TN and OC amounts is conceivable but that of continuous cropping calls for further elaboration. 3.2 Effects on maize growth and yield For the first cropping season, ANOVA revealed 2-way (stump cutting height x coppice thinning) and 3-way (tree species x stump cutting height x coppice thinning) interactions for maize diameter growth and survival respectively. During the first cropping season of 2008, results showed significant 2-way interaction between stump cutting height and coppice thinning on maize plant diameter growth ( p = 0.0443, Table 5 ), and 3-way interaction between coppice tree species, coppice stump cutting height and coppice thinning ( p = 0.0075, Table 4 ) but they were not significant for yields of maize grain, cobs and stovers (Table 5 ). However, during the second cropping season of 2009, effects of interactions between the factors on maize growth and yield were no longer significant (Table 5 ). Table 4 Summary of ANOVA ( p > F ) testing the effects of tree species, coppice cutting height and coppice thinning on maize plant growth and survival for the first and second cropping seasons at Maseyu, Morogoro, Tanzania. Source of variation 1 df 2008 2009 Height Diameter at 10 cm Arcsine transformed survival Height Diameter at 10 cm Arcsine transformed survival Block (Blk) 2 2 - - - - - - Tree species (Spp) 1 0.0003 0.0513 0.0052 0.7218 0.9961 0.2064 Blk x Spp 2 Cutting height (Cut) 2 0.8318 0.7973 0.7960 0.0258 < .0001 0.3856 Blk x Cut 4 - - - - - - Spp x Cut 2 0.1451 0.5077 0.7448 0.8196 0.3967 0.8168 Blk x Spp x Cut 4 - - - - - - Coppice thinning (Copth) 1 0.6189 0.0453 0.4533 0.0141 < .0001 0.4791 Blk x Copth 2 - - - - - - Spp x Copth 1 0.7613 0.6056 0.4533 0.8743 0.4550 0.6068 Blk x Spp x Cut 4 - - - - - - Cut x Copth 2 0.7613 0.0443 0.1386 0.6791 0.7773 0.0528 Blk x Cut x Copth 4 - - - - - - Spp*cut*coppthin 4 0.8258 0.6461 0.0075 0.8151 0.8954 0.4756 Blk*Spp*cut*coppthin 4 - - - - - - Residual error 5 - - - - - - Corrected total 44 - - - - - - 1 df = Degree of freedom, 2 No test statistics (i.e. F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning. Table 5 Summary of ANOVA ( p > F ) testing the effects of tree species, coppice cutting height and coppice thinning on maize grain, stover and cob yields in Mg ha − 1 for the first and second cropping seasons at Maseyu, Morogoro, Tanzania Source of variation df 1 2008 2009* Grain Stover Cobs Grain Stover Cobs Block (Blk) 2 2 - - - - - - Tree species (Spp) 1 0.0008 0.0070 0.0163 - 0.7211 - Blk x Spp 2 - - - - - - Cutting height (Cut) 2 0.2943 0.5423 0.1283 - < .0001 - Blk x Cut 4 - - - - - - Spp x Cut 2 0.2649 0.8089 0.6408 - 0.3908 - Blk x Spp x Cut 4 - - - - - - Coppice thinning (Copth) 1 0.2414 0.8733 0.4827 - < .0001 - Blk x Copth 2 - - - - - - Spp x Copth 1 0.6832 0.4421 0.7777 - 0.4651 - Blk x Spp x Cut 4 Cut x Copth 2 0.3975 0.2044 0.8817 - 0.7513 - Blk x Cut x Copth 4 - - - - - - Spp*cut*coppthin 4 0.0919 0.4070 0.5921 - 0.9417 - Blk*Spp*cut*coppthin 4 - - - - - - Residual error 5 - - - - - - Corrected total 44 - - - - - - 1 df = Degree of freedom, 2 No test statistics (i.e., F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning. *Grain and cobs were not produced in the second cropping season (2009). During the first cropping season, ANOVA revealed significant main effects ( p < 0.05) of coppice tree species on all of the assessed maize growth and yield variables with the exception of maize plant diameter but this trend was reversed in the second cropping season (Tables 4 and 5 ). Figure 3 shows the main effects of coppice tree species on maize growth and yield variables for the first and second cropping seasons. During the first cropping season, yields of grain (1.26 Mg ha − 1 ), cobs (0.3 Mg ha − 1 ) and stover (2.43 Mg ha − 1 ) in maize intercropped with A. versicolor were significantly ( p < 0.05) higher compared to that of maize intercropped with A. harveyi as well as continuous cropping treatment (Fig. 3 ). Corresponding values for continuous cropping treatment were 0.29 Mg ha − 1 , 0.06 Mg ha − 1 and 1.06 Mg ha − 1 for yield of maize grain, cobs and stover respectively. This is equivalent to yield gain in maize grain, cobs and stover by 334.5%, 129.2% and 400% relative to continuous cropping treatment as a result of first season intercropping with A. versicolor coppices respectively. The analogous increase in yield, relative to continuous cropping treatment, due to intercropping with A. harveyi coppices were 155.2%, 40.6% and 233%. The results indicate superiority of A. versicolor coppices over that of A. harveyi in improving yields of the intercropped maize. However, this trend was reversed in the second cropping season (Fig. 3 ) where, though not statistically significant, intercropping with coppices of any of the studied tree species tended to suppress maize growth and yield. During the second cropping season, there was no maize grain in any of the treatments due to sporadic rainfall. Despite the fact that there were no statistically significant differences, coppices of both tree species tended to suppress maize growth and yield in the second cropping season and the effect was similar for both tree species. Yields of maize stover, height and diameter growth were lower in intercropped maize relative to continuous cropping by 98–98.7%, 14.8–15.3% and 46.4–81.0% respectively. Coppice stump height and coppice thinning had no significant effects ( p > 0.5) on growth and yield of intercropped maize during the first cropping season, whereas their effects became significant ( p < 0.05) in the second cropping season (Table 5 ). Effects of coppice stump cutting height on growth and yield of intercropped maize for two consecutive cropping seasons are presented (Fig. 4). Though not significant, during the first cropping season, maize yields and growth tended to be higher in maize intercropped with coppices compared to continuous cropping treatment. The general trend was highest maize grain yield in coppices grown from stumps cut at the ground level. A similar pattern was observed for maize cob yields, whereas the pattern for stover yields was not clearly defined being highest in stumps cut at 90 cm above the ground, intermediate in stumps cut at the ground level and lowest in sumps cut at 30 cm from the ground level. During the first cropping season, maize grain yield ranged from 0.98 Mg ha − 1 for coppice stumps cut at 90 cm from the ground to 1.25 Mg ha − 1 for stumps cut at the ground level. This is in contrast to maize grain yield of 0.29 Mg ha − 1 recorded in continuous cropping treatment. These results translate into an increase of maize grain yields ranging from 237.9% for maize intercropped with coppices from stumps cut at 90 cm from the ground to 331% for stumps cut at the ground level. During the second cropping season, growth and yield of intercropped maize were reduced compared to the first cropping season but similar for all coppice stump height treatments; whereas they become significantly ( p < 0.05) lower compared to continuous cropping treatment (Fig. 4). In that season, stover yields ranged from 0.02 Mg ha − 1 for both stumps cut at 30 cm and 90 cm from the ground to 0.04 Mg ha − 1 for stumps cut at the ground level. This was in comparison to stover yield of 1.04 Mg ha − 1 in continuous cropping treatment. Figure 5 shows effects of coppice thinning on growth and yield of intercropped maize for two successive cropping seasons. During the first cropping season, maize grain yield for maize intercropped with thinned coppice treatment (0.97 Mg ha − 1 ) was slightly lower than that from no coppice thinning treatment (1.17 Mg ha − 1 ) but about twice as much as grain yield of 0.29 Mg ha − 1 from continuous cropping treatment (Fig. 5 ). A similar pattern was observed for cobs and stover yields as well as maize plant growth. The similarities in maize growth and yield between coppice thinning and no thinning treatments continued during the second cropping season but became significantly ( p < 0.05) lower than continuous cropping treatment (Table 5 ; Fig. 5 ). In the second cropping season, maize stover yield was reduced in coppice thinning and no coppice thinning treatments at exactly the same rate of about 85% to 0.3 Mg ha − 1 compared to stover yield of 2.03–2.09 Mg ha − 1 in first cropping season. This was significantly ( p < 0.05) lower than 1.04 Mg ha − 1 recorded in continuous cropping treatment. 4 Discussion 4.1 Effects of tree fallow on soils The OC content in 0–20 cm soil depth found in this study is within the range of 0.41–3.14% reported by [ 24 ] in the same area and 0.1 to 3.8% for the general miombo ecoregion [ 29 ]. Soil assessment prior to establishment of coppice experiments demonstrated the potential of AF in utilizing the tested tree species to increase OC and OM within a short period of four years. These results corroborate well with results reported by [ 15 ] for rotational woodlots in Tanzania. Other studies elsewhere found no significant increase in OC and OM within three to five years of AF due to the fact that processes to increase soil OC, OM and soil fertility in general occurred slowly taking several years to detect [ 20 ]. The plausible explanation for the lack of significant AF trees effects on OC, OM and soil fertility in some studies could be nutrient removals associated with intensive fodder, fuel wood and poles extraction during tree fallow phase [ 30 ]. In contrast, in this study and studies by [ 15 ] and [ 22 ], AF trees were not harvested until the canopy closure. Interim intensive harvesting of fodder and fuel wood from AF systems are likely to influence OC and OM build-up since they tend to expose the soils to high temperature leading to loss of C through oxidation [ 31 ] as well as limiting foliar mass deposits on the ground surface. The low base (Ca, K, Mg and Na) content found in this study is a characteristic of highly weathered soils [ 32 ] typical of miombo woodlands [ 29 ]. [ 29 ] found a significant relationship between ECEC of the soil and the amounts of clay and OC in the top soils. Thus, the low ECEC recorded in this study corresponds well to the low amounts of OM in the area. However, this study has shown the potential of the tested tree fallows in improving both OC and OM. After one cropping season, the amount of TN and OC recorded in coppice plots were significantly lower compared to continuous cropping plots. The most plausible explanation for this phenomenon is C loss to the atmosphere from the coppice plots. The magnitude of changes of SOM depends on the quantity and quality of prunings, soil type, system management, climate and duration of practice of the system [ 33 , 34 ]. Although the quantity of prunings added in coppice plots was higher than the continuous cropping plots, it is possible that the studied tree species produce prunings that are of high quality, in terms of low carbon - to - nitrogen (C:N) and lignin-to-nitrogen (L:N) ratios. Materials of this nature are likely to have negligible or little effects on soil C build up because C is returned to atmosphere via C evolution process. This proposition is supported by [ 35 ] who found that addition of plant materials of high quality to soil led to C loss rather than accumulation. This was probably aggravated by soil exposure to high temperatures when coppices were still young leading to oxidation [ 31 ] and hence loss of C to the atmosphere. This can also serve to explain the high amounts of TN and OC in the tree fallow plots associated with differences in microclimate compared to coppiced plots. However, it is important to note that the quality of prunings from the studied tree species was not assessed due to unforeseen budget constraint, thus this aspect calls for further investigation. Lack of significant effects of tree coppice cutting height and coppice thinning treatments on soil chemical properties is probably due to the fact that foliar biomass as a result of these treatments were on the lower side. Improvement in soil nutrient status in AF is mainly through nutrients released from mineralization of prunings [ 16 , 36 ]. According to [ 11 ], nutrient contributions from AF systems are positively correlated to the amount of prunings added to the soil. In this study, foliar biomass ranged from 2.18 Mg ha -1 in A. versicolor to 2.86 Mg ha -1 in A. harveyi , which is lower compared to other AF studies that reported improved soil chemical properties. [ 22 ] reported improved soil chemical properties in AF system in which foliage yield ranged from 6.3 to 20.2 Mg ha -1 . Besides yields of prunings, the effects of AF system on soil chemical properties can be influenced by nutrient contents and overall quality of the prunings such as C: N ratio that affects mineralization of nutrients [ 10 , 37 ]. This study did not assess these factors thus they require further investigation. 4.2 Effects on maize growth and yield This study has demonstrated an increase in maize grain yield of intercropped maize of up to 100% during the first cropping season as compared to continuous cropping. This could be attributed to fertility improvement as a result of AF tree coppices related to various mechanisms such as biological N fixation, pumping up or retrieval of nutrients from lower soil horizons and interception of nutrients that would otherwise be lost through leaching and surface runoff and release of nutrients during litter and root decomposition [ 9 , 34 , 36 ]. Probably the increased maize yield in intercropped maize could be attributed to these mechanisms. Significant reduction in maize stover yields for maize intercropped with coppices could be attributed to combination of competition for light as result of shading, and competition for water resulting from developed tree root system [ 22 ]. These results are consistent with other simultaneous AF system studies [ 15 , 16 , 21 ]. In a semiarid area of Tanzania, [ 22 ] reported progressive reduction of yields of maize intercropped with Australian Acacias despite the fact that trees improved soil chemical properties. In Kenya, [ 38 ] reported decreased yield of maize intercropped with Grevillea robusta after three years of intercropping. Similar results have been reported by [ 39 ] in Kenya. It is important to note that the pattern of the effects of tree age on the nature and magnitude of competitiveness of AF trees varies with planting density (widely spaced trees taking longer to reduce crop yields) and is influenced by climate and species of crop involved [ 34 , 40 , 41 ]. These aspects were not investigated in the present study, thus require further investigation. Conclusion Intercropping coppices of the studied trees with maize increased maize grain yield by 100% compared to continuous cropping treatment in the first cropping season suggesting soil amelioration effects of these tree species and the potential to boost livelihoods and achieve SDGs. However, in the second-year reduction in yields of maize intercropped with coppices of the studied tree species was observed indicating increasing competitive effects of the coppices of these tree species with age. Based on their positive effects on soil fertility, the studied tree species are recommended for on-farm planting for soil improvement. Planting these tree species in sequential AF systems such as improved fallow, intensive pruning of coppices or wider spacing in intercropping systems may reduce their competitive effects on the companion crops. The effects of AF system on soil chemical properties can be influenced by nutrient contents and overall quality of the prunings such as C: N ratio that affects mineralization of nutrients. Thus, these aspects require further investigation. Declarations Declaration of competing interest There are no conflicts of interest Acknowledgements Norwegian Agency for Development Cooperation (NORAD) through the Programme for Agricultural and Natural Resources Transformation for Improved Livelihoods (PANTIL) of the Sokoine University of Agriculture (SUA), Tanzania supported this study. Department of Ecosystems and Conservation, College of Forestry, Wildlife and Tourism of SUA provided logistical support. Land for experiments and field assistance were provided by Maseyu villagers. Authors’ contributions VGV and SAOC conceptualized and designed the study; VGV investigated, curated and analysed data under the supervision of SAOC; SMA did additional data analysis and prepared the initial draft of the manuscript; VGV and SAOC improved the draft. All authors read and approved the final manuscript. Data availability statement Data used in this research is available upon official request from the main author after the date of publication. 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In: Kimble JM, Follett RF, Stewart BA (eds) Lal R. Lewis Publishers, Assessment methods for soil carbon. 2001; 495–511. Rao MR, Nair PKK, Ong CK. Biophysical interactions in tropical agroforestry systems. Agrofor Syst. 1998; 38:3-50. Vanlauwe B, Kihara J, Chivenge P, Pypers P, Coe R, Six J. Agronomic use efficiency of N fertilizer in maize-based systems in Sub-Saharan Africa within the context of integrated soil fertility management. Plant Soil 2011; 339: 35–50. Ong CK, Black CR, Wallace JS, Khan AAH, Lott JE, Jackson NA, Howard SB, Smith DM. Productivity, microclimate and water use in Grevillea robusta-based agroforestry systems on hillslopes in semi-arid Kenya. Agric Ecosyst Environ. 2000; 80: 121–141. Lott JE, Ong CK, Black CR. Long-term productivity of a Grevillea robusta-based overstorey agroforestry system in semi-arid Kenya. II. Crop growth. For Ecol Manag. 2000; 139:187–201. Muthuri CW, Ong CK, Black CR, Ngumi VW, Mati BM. Tree and crop productivity in Grevillea, Alnus and Paulownia-based agroforestry systems in semi-arid Kenya. For Ecol Manag. 2005; 212:23–39. Yin RS, He Q. The spatial and temporal effects of paulownia intercropping: the case of northern China. Agrofor Syst. 1997; 37:91–109. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-430132","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":22211317,"identity":"cc4f8e82-f756-4762-8c48-b80020ccc4d3","order_by":0,"name":"Vincent G. Vyamana","email":"","orcid":"","institution":"P.O. Box 1349, Morogoro, Tanzania","correspondingAuthor":false,"prefix":"","firstName":"Vincent","middleName":"G.","lastName":"Vyamana","suffix":""},{"id":22211318,"identity":"21a1089b-aaaf-46d5-886b-53926cfe2d49","order_by":1,"name":"Shabani A.O. 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This map has been provided by the authors.","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/39df43d7ed9aca0657f7a999.jpg"},{"id":8290543,"identity":"e4f461d2-530f-4fad-ba8b-c477bbbd7dda","added_by":"auto","created_at":"2021-04-21 17:24:53","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":112832,"visible":true,"origin":"","legend":"Effects of three-year tree fallow on soil total Nitrogen (a) soil organic Carbon (b), soil extractable Phosphorus (c), effective cation exchange capacity (ECEC) (d), exchangeable Calcium (e), exchangeable Magnesium (f), exchangeable Potassium (g) and exchangeable Sodium (h) assessed just before planting first maize crop in 2008 at Maseyu, Morogoro, Tanzania. Ah = Albizia harveyi, Av = Albizia versicolor and CC = Continuous cropping. For each figure, means marked by the same letter indicate means that are not statistically different at p \u003c 0.05 according to DMRT. Vertical bars indicate standard errors of means (n = 3).","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/9c758c5405f801b3c890c2f7.jpg"},{"id":8291072,"identity":"f9f33e75-19ea-4a00-9cb3-00d589e5d80f","added_by":"auto","created_at":"2021-04-21 17:27:54","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":115405,"visible":true,"origin":"","legend":"The effects of coppice tree species on intercropped maize grain (a), stover (b), (c) cob yields, maize plant height growth (d), diameter growth (e) and survival for the first and second cropping seasons at Maseyu, Morogoro, Tanzania. Treatments were coppice tree species Ah = Albizia harveyi and Av = Albizia versicolor; and CC = continuous cropping. For each figure and within each cropping season, means marked by the same letter are not statistically different at p \u003c 0.05 according to DMRT. Vertical bars indicate standard errors of means (n = 21 for tree species and n = 6 for continuous cropping).","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/02a060b91c15894c228d80ff.jpg"},{"id":8291069,"identity":"075874dc-d159-471d-a24a-ebf99d98448c","added_by":"auto","created_at":"2021-04-21 17:27:54","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":131558,"visible":true,"origin":"","legend":"The effects of coppice stump heights on yields of maize grain (a), stover (b), cob (c), maize plant height growth (d), diameter growth (e) and survival for the first and second cropping seasons at Maseyu, Morogoro, Tanzania. Treatments were C0 = coppice stumps cut at the ground level, C30 = coppice stumps cut at 30 cm from the ground level, C90 = coppice stumps cut at 90 cm from the ground level, C∞ = Tree fallow and CC = continuous cropping. For each figure and within each cropping season, means marked by the same letter are not statistically different at p \u003c 0.05 according to DMRT. Vertical bars indicate standard errors of means (n = 7 for tree species and n = 3 for continuous cropping).","description":"","filename":"Fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/b9c6c417c08a8e2d416a6473.jpg"},{"id":8291574,"identity":"11f38dd1-4900-474e-b990-792af85f3a0e","added_by":"auto","created_at":"2021-04-21 17:30:54","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":110568,"visible":true,"origin":"","legend":"The effects of coppice thinning on yields of maize grain (a), stover (b), cob (c), maize plant height growth (d), diameter growth (e) and survival for the first and second cropping seasons at Maseyu, Morogoro, Tanzania. Treatments were TH0 = no coppice thinning, TH1 = coppice thinned to leave two coppice stems per stump, TH∞ = Tree fallow and CC = continuous cropping. For each figure and within each cropping season, means marked by the same letter are not statistically different at p \u003c 0.05 according to DMRT. Vertical bars indicate standard errors of means (n = 7 for tree species and n = 3 for continuous cropping).","description":"","filename":"Fig5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/d1d8f97a88ac99cce30961ed.jpg"},{"id":13688442,"identity":"08712c11-6033-4098-b8ec-4c502928263e","added_by":"auto","created_at":"2021-09-17 12:25:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":820272,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-430132/v1/0565f02e-823a-457e-adf9-6460bb5aa117.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSoil Nutrients and Maize Yields Responses to Agroforestry Tree Post-fallows Management in Tanzania\u003c/p\u003e","fulltext":[{"header":"1 Introduction","content":" \u003cp\u003eAgriculture employs about 75% of the workforce and forms a backbone of many developing economies of countries in sub-Sahara Africa (SSA) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It has therefore the potential to contribute greatly to achieving Sustainable Development Goals (SDGs) particularly poverty eradication, attaining zero hunger and ensuring responsible consumption and production. Adopted unanimously by all UN member states in 2015, SDGs is a collection of global goals set to ensure a better and sustainable future for all citizens by 2030 [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Food production in SSA has increased during the last few decades as a result of expansion of area cultivated into forests and woodlands rather than increased productivity leading to deforestation and land degradation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Another concern is the fact that population growth estimated at 2.7% in 2017 has already outpaced the increase in food production. Thus, there has been a parallel decline in per capita food production by about 2% per year [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Available records [e.g. 5] show that since the 1970s, Africa has been a net exporter of food but in recent times around \u003cspan\u003e$\u003c/span\u003e 35\u0026nbsp;billion was spent for annual food imports [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. More also, currently, two-thirds of African countries are net food importers [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIncreasing human population coupled with use of inappropriate agricultural and other land management technologies are among the root causes of the problems of declining per capita food production in the SSA [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] with negative consequence on SDGs. The escalating population has constrained traditional shifting cultivation that used to be successful in sustaining crop yields. As a result, smallholder farmers have resorted to short fallow or continuous cropping with no external inputs such as fertilizers due to high farm gate prices [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This has resulted in declining soil fertility and crop yields as well as household incomes due to soil nutrient depletion through repeated crop harvest and soil erosion [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSoil fertility depletion is the major cause of declining per capita food production and the concomitant widespread food shortage, low income and perpetual poverty in Africa [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This is a consequence of breakdown of traditional shifting cultivation or bush fallow system that was used successfully in the past to replenish and maintain soil fertility [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Shifting cultivation is currently not feasible for most farmers due to dwindling landholdings as a result of increasing population. Farmers are forced to intensify land use by reducing fallow periods to a level that is below the minimum required to maintain soil fertility or practice continuous cropping [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. As a result, nutrients are being depleted through nutrient mining via repeated harvesting. In such a situation, the only viable options for replenishment and sustaining soil fertility appear to be application of mineral fertilizers and green manuring [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] but these are constrained too. Most of the farmers lack the required capital to use adequate and appropriate specification of mineral fertilizers that can counter the effect of short or no fallow on soils [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. While organic manuring could be an option, but the practice is limited by bulky nature of the organic matter (OM) and unavailability [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAgroforestry (AF) practices have been identified as one of appropriate sustainable solutions to the problems of soil fertility depletion, low crop productivity and woodfuel scarcity [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and can reduce wood harvesting pressure on natural forests and woodlands thereby reducing the rate of deforestation. However, despite the potential of AF practices to fix Nitrogen (N), utilization of indigenous tree species in AF has received little attention [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] due to low growth rate and inadequate silvicultural knowledge. Where woodfuel scarcity is acute, crop residues and livestock manure are used as supplementary energy sources [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], which means little or no OM is available to be returned to the soil in farms. This aggravates the vicious cycle of low agricultural productivity, food shortage, low income and perpetual poverty. Therefore, alternative land use strategies to improve soil fertility and woodfuel supplies are urgently needed to sustain agricultural productivity, conserve the remaining forests and woodlands and ensure achievement of the SDGs.\u003c/p\u003e \u003cp\u003eWith few exceptions, most AF studies on evaluation and selection of AF trees/shrubs in Tanzania have focused on exotic multipurpose tree/shrub species [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. This is notwithstanding the fact that the indigenous tree/shrub species are more adapted to local environmental conditions and can meet local requirements better than exotics [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In addition, there is increasing realization that indigenous tree species can be more efficient in improving soil fertility and less competitive to the companion crops, especially for soil moisture [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. This study was therefore initiated with the overall objective of assessing the potential for utilizing AF tree species (\u003cem\u003eAlbizia harveyi\u003c/em\u003e and \u003cem\u003eAlbizia versicolor\u003c/em\u003e) and management of their fallows for increasing soil nutrients and yield of maize (\u003cem\u003eZea mays\u003c/em\u003e). Maize was used in the study because it is the most widely cultivated cereal of great importance to food security and livelihoods in SSA.\u003c/p\u003e "},{"header":"2 Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003e2.1 Study area\u003c/h2\u003e\n\u003cp\u003eThe study area (i.e. Maseyu) is located about 50 km east of Morogoro and 150 km west of Dar es Salaam, Tanzania (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The area experiences tropical and sub-humid climate [23). It has a bimodal rainfall pattern with annual mean of 900 mm and seasonally distributed on wet (November to May) and dry (June to October) seasons. The mean annual temperature is 24.3\u0026deg;C while the minimum and maximum annual temperatures are 18.6 and 28.8\u0026deg;C, respectively.\u003c/p\u003e\n\u003cp\u003eBecause of favourable rainfall and temperature small holder farmers practice rain-fed agriculture where maize (\u003cem\u003eZea mays\u003c/em\u003e L.), sorghum (\u003cem\u003eSorghum bicolour\u003c/em\u003e L. Moench) and garden peas (\u003cem\u003ePisum sativum\u003c/em\u003e L.) are mainly grown. Recently a small portion of local community members have started keeping domestic animals including cattle, sheep and goats. Charcoal production outside agricultural area takes place and contributes significantly to the household income. The area is surrounded by miombo woodland dominated by trees of \u003cem\u003eJulbernardia globiflora\u003c/em\u003e (Benth.) Troupin and \u003cem\u003eCombretum\u003c/em\u003e spp. On the northern side there is Kitulanghalo Forest Reserve, while on the southern side there is a General Land. Precambrian Usagaran metasedimentory rocks consisting of garnet biotite gneiss dominate the area. Thus, mixed alluvial and colluvial deposits tend to occur in low-lying areas [\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e]. The soils of the area are well drained, red, acid\u0026ndash;neutral, sandy clay loams with brown friable top soil and are generally nutrient poor.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n\u003ch2\u003e2.2 Experimental design and establishment\u003c/h2\u003e\n\u003cp\u003eA 2 x 2 x 4 x 2 factorial experiment with three replications was established in a randomized arrangement to assess tree coppice intercropping of \u003cem\u003eAlbizia harveyi\u003c/em\u003e (Ah) and \u003cem\u003eAlbizia versicolor\u003c/em\u003e (Av) for soil fertility and maize yield improvements (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The experiment was established using four-years plantations of Ah and Av planted separately on the same site. Prior to establishment of the experiment, the site was prepared by clearing all vegetation followed by plowing by a farm tractor and pitting using hand hoe where the pit size was 20 cm x 30 cm x 30 cm. The plantations were kept clean weeded all the time for four years prior to establishment of the cropping system experiment. Plots were rectangular (12 m x 6 m) and plots and blocks were separated by 2.5 and 3 m-unplanted buffer strips, respectively. For each study species, there were a total of 18 such plots of which 14 were used for this study.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eA factorial experimental design for testing the effects of \u003cem\u003eAlbizia harveyi\u003c/em\u003e and \u003cem\u003eAlbizia versicolor\u003c/em\u003e and management of their fallows on maize yield and soil nutrients\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFactor one\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFactor two\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFactor three\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFactor four\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTwo levels of study species\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTwo levels of cropping systems\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFour levels of tree cutting heights\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTwo levels of coppice thinning\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eAh\u0026thinsp;=\u0026thinsp;\u003cem\u003eA\u003c/em\u003e. \u003cem\u003eharveyi\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAv\u0026thinsp;=\u0026thinsp;\u003cem\u003eA\u003c/em\u003e. \u003cem\u003eversicolor\u003c/em\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ei) IC0\u0026thinsp;=\u0026thinsp;Continuous maize cropping (control)\u003c/p\u003e\n\u003cp\u003eii) IC1\u0026thinsp;=\u0026thinsp;maize intercropped with coppices\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ei) C0\u0026thinsp;=\u0026thinsp;Trees not cut (tree fallow)\u003c/p\u003e\n\u003cp\u003eii) C1\u0026thinsp;=\u0026thinsp;5 cm (ground level\u003c/p\u003e\n\u003cp\u003eiii) C2\u0026thinsp;=\u0026thinsp;30 cm above the ground\u003c/p\u003e\n\u003cp\u003eiv) C3\u0026thinsp;=\u0026thinsp;90 cm above the ground\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ei) TH0\u0026thinsp;=\u0026thinsp;All coppice shoots left (no thinning)- control\u003c/p\u003e\n\u003cp\u003eii) TH1\u0026thinsp;=\u0026thinsp;Coppices thinned to leave two coppice shoots per stump\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEstablishment of cropping experiment involved cutting trees at respective heights as per cutting height treatments (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Land was prepared using a hand hoe, and maize seeds of TMV-1 variety were sown for two cropping seasons at a spacing of 30 cm within row and 75 cm between rows giving a population of 44,444 maize plants per ha. Thinning was applied when coppices reached 10 cm height, which was achieved after tree cutting. Subsequent coppice thinning was maintained at the same interval of four months. During the first coppice thinning occasion, the two tallest coppices were left per thinned stump and any coppices that sprouted were subsequently removed.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003e2.3 Soil fertility, maize growth and yield assessments\u003c/h2\u003e\n\u003cp\u003eJust before maize sowing in each season, soil samples were taken from 4 randomly selected points in each intercropped plot at a depth of 0\u0026ndash;15 cm using soil auger leaving 1 m border strip on both sides of each plot. These samples were mixed thoroughly and sub-sampled to get a composite sample. The composite soil samples for each plot were transported to the laboratory for soil organic matter (SOM) and soil fertility analysis. All soil sub-samples were oven-dried (70\u003csup\u003e0\u003c/sup\u003eC) to constant weight and sun dried, respectively. The dried samples were then ground to pass through a 1 mm sieve and analysed for Total N (TN), extractable Phosphorus (P), Potassium (K), Magnesium (Mg), Calcium (Ca) and total soil organic Carbon (OC). Extractable P, K, Ca and Mg were determined by simultaneous Inductive Coupled Plasma (ICP) Emission Spectroscopy technique in acid digested samples while Total N was determined by the Kjeldahl procedure. Soil OC was determined by wet calorimetric method [\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eMaize plants were measured for diameter at 30 cm above ground and height at maturity. Height was measured to the nearest 0.01 m using a graduated pole while basal diameter at 10 cm (D10) was measured to the nearest 0.01 cm using a veneer caliper. At maturity, a total of 20 maize plants in the middle two rows were harvested, stems cut at ground level, weighed fresh and sub-sampled for dry weight determination. Also, maize cobs were harvested, shelled and both shaft and grain weighed fresh and sub-sampled for dry weight determination. Assessment of coppice growth was done at the ages of 6, 12, 18 and 24 months. During each assessment, all surviving coppices were measured for D10 and total height. The tally of height and D10 provided the number of coppice stems per stump.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003e2.4 Statistical analyses\u003c/h2\u003e\n\u003cp\u003eVisual inspection and significance test were used to test for standard parametric statistical assumptions of normality and constant variance of residuals. Visual inspection was done by plotting the residuals against normal scores and predicted values while significance test was executed using Shapiro-Wilks\u0026rsquo;s test [\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e]. Soil Sodium (Na) content, maize plant survival, coppice mortality and stump survival data sets violated the requirements for normality and homoscedasticity. Thus, soil Na content data were square-root transformed; and maize plant survival, coppice mortality, and stump survival data sets were arcsine transformed to correct for deviations from parametric statistical assumptions. However, only non-transformed data are presented for clarity [\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e]. Plot means were subjected to Analysis of Variance (ANOVA) using the General Linear Model procedure in Statistical Analysis System (SAS) at 5% level of statistical significance. In the study, block and block-by-treatment interactions were error terms in the model. The ANOVA for maize and soil data tested the effects of two study tree species, three cropping systems, four tree cutting heights and two coppice thinning regimes (a 2 x 3 x 4 x 2 factorial experiment) replicated three times in a RCBD (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). For the tree biomass data, the analysis was carried out as a 2 x 2 x 4 x 2 factorial experiment since one level of cropping system did not have tree biomass data. All statistical analyses were done by using SAS version 8 [\u003cspan class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003e3.1 Effects of tree fallow on soils\u003c/h2\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e shows results for soil chemical properties from tree fallows of \u003cem\u003eA. harveyi\u003c/em\u003e and \u003cem\u003eA. versicolor\u003c/em\u003e at three years old just before cutting to establish the experiment to test the effects of \u003cem\u003eA\u003c/em\u003e. \u003cem\u003eharveyi\u003c/em\u003e and \u003cem\u003eA\u003c/em\u003e. \u003cem\u003eversicolor\u003c/em\u003e and management of their fallows on maize yield and soil nutrients. At that age of fallow TN of top soil at a depth of 0\u0026ndash;20 cm did not differ significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) from that recorded in continuous cropping plots (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e-a). The TN in tree fallow ranged from 0.073% in \u003cem\u003eA. harveyi\u003c/em\u003e to 0.11% in \u003cem\u003eA\u003c/em\u003e. \u003cem\u003eversicolor\u003c/em\u003e tree fallows compared to 0.06% in the continuous cropping. Though not statistically significant, the values of TN recorded in tree fallows were higher by 21.7\u0026ndash;83.3% compared to continuous cropping plots for \u003cem\u003eA. harveyi\u003c/em\u003e and \u003cem\u003eA. versicolor\u003c/em\u003e, respectively. This indicates a slightly superior ability of \u003cem\u003eA. versicolor\u003c/em\u003e fallow to increase TN as compared to \u003cem\u003eA. harveyi\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eOrganic Carbon was significantly higher (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) under the tree fallows compared to continuous cropping plots. In comparison with continuous cropping plots, amount of OC was higher by 41% and 56% in \u003cem\u003eA. harveyi\u003c/em\u003e and \u003cem\u003eA. versicolor\u003c/em\u003e tree fallows respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e-b). OC ranged from 0.96% in \u003cem\u003eA. harveyi\u003c/em\u003e to 1.06% in \u003cem\u003eA. versicolor\u003c/em\u003e tree fallows. This was in contrast to 0.68% OC recorded in continuous cropping plots. Despite the lack of statistically significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05), soils under \u003cem\u003eA. versicolor\u003c/em\u003e tree fallow contained 67.5% more extractable P compared to the continuous cropping plots (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e-c).\u003c/p\u003e\n\u003cp\u003eEffects of tree fallow on ECEC were not significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) but it was highest (22.04 Cmol kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), intermediate (18.37 Cmol kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and lowest (17.38 Cmol kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) under \u003cem\u003eA. versicolor\u003c/em\u003e fallow, \u003cem\u003eA. harveyi\u003c/em\u003e fallow and continuous cropping plots, respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e-d). This corresponds to improvement in ECEC by 5.7\u0026ndash;26.8% as a result of tree fallow management. With the exception of Na, \u003cem\u003eA. versicolor\u003c/em\u003e tree fallow recorded significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) highest amounts of soil cations (Ca, Mg and K) in 0\u0026ndash;20 cm soil depth compared to the continuous cropping (Figs.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e-e, f, g and h). There was no significant interaction (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) of the factors for all soil chemical properties assessed except for ECEC, which showed significant interaction between tree species and cutting height (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). However, there were no significant 3-way interactions among the factors.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSummary of ANOVA (\u003cem\u003ep\u0026thinsp;\u0026gt;\u0026thinsp;F\u003c/em\u003e) testing the effects of tree species, coppice cutting height and coppice thinning on soil chemical properties for the second cropping season at Maseyu, Morogoro, Tanzania.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSource of variation\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003edf\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eTN%\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eOC%\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eP\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eECEC\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCa\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMg\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eK\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNa\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlock (Blk)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTree species (Spp)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8415\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4756\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0045\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0397\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0562\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0007\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCutting height (Cut)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6768\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3577\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6279\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2948\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9864\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2873\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5441\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7240\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4209\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6450\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1252\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0238\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6703\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8297\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3415\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7626\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCoppice thinning (Coppthin)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4864\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0209\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4013\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5622\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0524\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9537\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8167\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0965\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1853\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2797\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2511\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCut x Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7373\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3511\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7135\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3037\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9196\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3378\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3344\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4849\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut x Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp*cut* Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7764\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5586\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5790\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3522\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3099\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2053\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3764\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9521\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk*Spp*cut* Coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eResidual error\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCorrected total\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e45\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"10\"\u003e\u003csup\u003e1\u003c/sup\u003edf = numerator degree of freedom; \u003csup\u003e2\u003c/sup\u003eNo test statistics (i.e., F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere were significant effects (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) of tree species, stump cutting height and coppice thinning on the assessed soil chemical properties (Tables\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eEffects of tree species, coppice stump cutting height and coppice thinning on soil chemical properties during the second season of intercropping with maize at Maseyu, Morogoro, Tanzania\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eTreatment (Unit)\u0026dagger;\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e%\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e%\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003emg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"6\" align=\"left\"\u003e\n\u003cp\u003eECEC and bases (Cmole (+) kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eTN\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eOC\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eExtrac. P\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eOM\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eECEC\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCa\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMg\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eK\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNa\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"12\" align=\"left\"\u003e\n\u003cp\u003eTree species\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eA. harveyi\u003c/em\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026sect;\u0026nbsp;0.07c\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.66b\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.43a\u003c/p\u003e\n\u003cp\u003e(0.07)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.41a\u003c/p\u003e\n\u003cp\u003e(0.09)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e17.37a\u003c/p\u003e\n\u003cp\u003e(0.08)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2.77b\u003c/p\u003e\n\u003cp\u003e(0.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.15b\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.45b\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.20b\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eA. versicolor\u003c/em\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.38a\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.27a\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e4.84a\u003c/p\u003e\n\u003cp\u003e(0.07)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e11.31a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e17.66a\u003c/p\u003e\n\u003cp\u003e(0.08)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4.24a\u003c/p\u003e\n\u003cp\u003e(0.05)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.46b\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.56b\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.16c\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous cropping\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.11b\u003c/p\u003e\n\u003cp\u003e(0.24)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.85b\u003c/p\u003e\n\u003cp\u003e(0.41)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.13a\u003c/p\u003e\n\u003cp\u003e(0.31)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.6a\u003c/p\u003e\n\u003cp\u003e(0.44)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e10.35a\u003c/p\u003e\n\u003cp\u003e(1.00)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2.64b\u003c/p\u003e\n\u003cp\u003e(0.46)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3.98a\u003c/p\u003e\n\u003cp\u003e(0.69)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.37a\u003c/p\u003e\n\u003cp\u003e(0.40)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5.09a\u003c/p\u003e\n\u003cp\u003e(0.97)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"12\" align=\"left\"\u003e\n\u003cp\u003eCoppice stump cutting height\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0 cm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07a\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.67a\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e4.67a\u003c/p\u003e\n\u003cp\u003e(0.13)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e11.57a\u003c/p\u003e\n\u003cp\u003e(0.15)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18.36a\u003c/p\u003e\n\u003cp\u003e(0.14)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.78a\u003c/p\u003e\n\u003cp\u003e(0.11)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.42a\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.51a\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.18a\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e30 cm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.53a\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.71a\u003c/p\u003e\n\u003cp\u003e(0.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.38a\u003c/p\u003e\n\u003cp\u003e(0.13)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.27a\u003c/p\u003e\n\u003cp\u003e(0.19)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18.02a\u003c/p\u003e\n\u003cp\u003e(0.14)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.73a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.16a\u003c/p\u003e\n\u003cp\u003e(0.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.48a\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.18a\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e90 cm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07a\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.80a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.55a\u003c/p\u003e\n\u003cp\u003e(0.08)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e13.79a\u003c/p\u003e\n\u003cp\u003e(0.11)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e16.70a\u003c/p\u003e\n\u003cp\u003e(0.25)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.68a\u003c/p\u003e\n\u003cp\u003e(0.12)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.38a\u003c/p\u003e\n\u003cp\u003e(0.17)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.56a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.19a\u003c/p\u003e\n\u003cp\u003e(0.24)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTree fallow\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07a\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.7a\u003c/p\u003e\n\u003cp\u003e(0.07)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.39a\u003c/p\u003e\n\u003cp\u003e(0.30)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e9.661a\u003c/p\u003e\n\u003cp\u003e(0.26)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e16.43a\u003c/p\u003e\n\u003cp\u003e(0.29)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.14a\u003c/p\u003e\n\u003cp\u003e(0.19)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3.94a\u003c/p\u003e\n\u003cp\u003e(0.09)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.38a\u003c/p\u003e\n\u003cp\u003e(0.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.18a\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous cropping\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07a\u003c/p\u003e\n\u003cp\u003e(0.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.54a\u003c/p\u003e\n\u003cp\u003e(0.31)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.60a\u003c/p\u003e\n\u003cp\u003e(0.28)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5.198a\u003c/p\u003e\n\u003cp\u003e(0.44)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10.35a\u003c/p\u003e\n\u003cp\u003e(0.75)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.64a\u003c/p\u003e\n\u003cp\u003e(0.35)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.22a\u003c/p\u003e\n\u003cp\u003e(0.51)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.46a\u003c/p\u003e\n\u003cp\u003e(0.30)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5.09a\u003c/p\u003e\n\u003cp\u003e(0.73)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"12\" align=\"left\"\u003e\n\u003cp\u003eCoppice thinning\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eThinned\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07c\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.72b\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e4.736a\u003c/p\u003e\n\u003cp\u003e(0.09)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.43a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.42ab\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.52a\u003c/p\u003e\n\u003cp\u003e(0.07)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.31b\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.52b\u003c/p\u003e\n\u003cp\u003e(0.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.19b\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNot thinned\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.07c\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.73b\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.67a\u003c/p\u003e\n\u003cp\u003e(0.09)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.66a\u003c/p\u003e\n\u003cp\u003e(0.12)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.97a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e3.95a\u003c/p\u003e\n\u003cp\u003e(0.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.32b\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.50b\u003c/p\u003e\n\u003cp\u003e(0.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.19b\u003c/p\u003e\n\u003cp\u003e(0.01)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTree fallow\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.30a\u003c/p\u003e\n\u003cp\u003e(0.10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.08a\u003c/p\u003e\n\u003cp\u003e(0.20)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e5.34a\u003c/p\u003e\n\u003cp\u003e(0.15)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8.95a\u003c/p\u003e\n\u003cp\u003e(0.22)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.67c\u003c/p\u003e\n\u003cp\u003e(0.50)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.67a\u003c/p\u003e\n\u003cp\u003e(0.23)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2.51a\u003c/p\u003e\n\u003cp\u003e(0.34)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.90a\u003c/p\u003e\n\u003cp\u003e(0.20)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.21b\u003c/p\u003e\n\u003cp\u003e(0.48)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous maize cropping\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.22b\u003c/p\u003e\n\u003cp\u003e(0.23)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.95ab\u003c/p\u003e\n\u003cp\u003e(0.38)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.66a\u003c/p\u003e\n\u003cp\u003e(0.39)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.27a\u003c/p\u003e\n\u003cp\u003e(0.64)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.27c\u003c/p\u003e\n\u003cp\u003e(0.45)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e2.13a\u003c/p\u003e\n\u003cp\u003e(0.46)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.33b\u003c/p\u003e\n\u003cp\u003e(0.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.49b\u003c/p\u003e\n\u003cp\u003e(0.15)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2.62a\u003c/p\u003e\n\u003cp\u003e(0.04)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"12\"\u003e\u0026dagger;Means for each individual factor are averaged over all other treatments; \u0026sect;Mean of three replicates with standard error in parentheses; within each category means in the same column followed by the same letters are not statistically different at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 according to DMRT.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSignificant effects of tree species on soil chemical properties were detected for TN, OC and soil cations (Ca, Mg and Na). On the other hand, coppice thinning had significant effects on TN, OC, ECEC as well as cations (Mg, K and Na). The overlaps of the effects of these two factors are revealing but it is worth to emphasize that there were no any significant interactions between these two factors.\u003c/p\u003e\n\u003cp\u003eResults showed no significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) between the two levels of coppice thinning for TN and OC but both recorded similar and significantly lower amounts of TN and OC compared to continuous cropping as well as tree fallows. The same pattern was observed for effects of thinning on amounts of Mg, K and Na. However, the pattern was reversed for ECEC, which was significantly highest (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in thinned and unthinned coppices compared to tree fallow and maize cropping. The superiority of the tree fallows over both thinned and not thinned coppice plots with regard to soil TN and OC amounts is conceivable but that of continuous cropping calls for further elaboration.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003e3.2 Effects on maize growth and yield\u003c/h2\u003e\n\u003cp\u003eFor the first cropping season, ANOVA revealed 2-way (stump cutting height x coppice thinning) and 3-way (tree species x stump cutting height x coppice thinning) interactions for maize diameter growth and survival respectively. During the first cropping season of 2008, results showed significant 2-way interaction between stump cutting height and coppice thinning on maize plant diameter growth (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0443, Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e), and 3-way interaction between coppice tree species, coppice stump cutting height and coppice thinning (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0075, Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e) but they were not significant for yields of maize grain, cobs and stovers (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). However, during the second cropping season of 2009, effects of interactions between the factors on maize growth and yield were no longer significant (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab4\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSummary of ANOVA (\u003cem\u003ep\u0026thinsp;\u0026gt;\u0026thinsp;F\u003c/em\u003e) testing the effects of tree species, coppice cutting height and coppice thinning on maize plant growth and survival for the first and second cropping seasons at Maseyu, Morogoro, Tanzania.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSource of variation\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003edf\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e2008\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e2009\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eHeight\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eDiameter at 10 cm\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eArcsine transformed survival\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eHeight\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eDiameter at 10 cm\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eArcsine transformed survival\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlock (Blk)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTree species (Spp)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0003\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0513\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0052\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7218\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9961\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2064\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCutting height (Cut)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8318\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7973\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7960\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0258\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3856\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1451\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5077\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7448\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8196\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3967\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8168\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCoppice thinning (Copth)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6189\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0453\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4533\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0141\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4791\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7613\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6056\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4533\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8743\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4550\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6068\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCut x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7613\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0443\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1386\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6791\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7773\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0528\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp*cut*coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8258\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6461\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0075\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8151\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8954\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4756\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk*Spp*cut*coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eResidual error\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCorrected total\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e44\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"8\"\u003e\u003csup\u003e1\u003c/sup\u003edf = Degree of freedom, \u003csup\u003e2\u003c/sup\u003eNo test statistics (i.e. F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab5\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSummary of ANOVA (\u003cem\u003ep\u0026thinsp;\u0026gt;\u0026thinsp;F\u003c/em\u003e) testing the effects of tree species, coppice cutting height and coppice thinning on maize grain, stover and cob yields in Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003efor the first and second cropping seasons at Maseyu, Morogoro, Tanzania\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSource of variation\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003edf\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e2008\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e2009*\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGrain\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eStover\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCobs\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGrain\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eStover\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCobs\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlock (Blk)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTree species (Spp)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0008\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0070\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0163\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7211\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCutting height (Cut)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2943\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5423\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1283\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2649\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8089\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6408\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3908\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCoppice thinning (Copth)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2414\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8733\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4827\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;.0001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.6832\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4421\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7777\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4651\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Spp x Cut\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCut x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3975\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.2044\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8817\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.7513\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk x Cut x Copth\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSpp*cut*coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0919\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.4070\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5921\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.9417\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBlk*Spp*cut*coppthin\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eResidual error\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCorrected total\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e44\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"8\"\u003e\u003csup\u003e1\u003c/sup\u003edf = Degree of freedom, \u003csup\u003e2\u003c/sup\u003eNo test statistics (i.e., F-ratios and probabilities) for replication and replication-by-treatment interactions because these were specified in the error terms of the General Linear Model of SAS for testing main and interaction effects of tree species, coppice cutting height and coppice thinning. *Grain and cobs were not produced in the second cropping season (2009).\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDuring the first cropping season, ANOVA revealed significant main effects (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) of coppice tree species on all of the assessed maize growth and yield variables with the exception of maize plant diameter but this trend was reversed in the second cropping season (Tables\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows the main effects of coppice tree species on maize growth and yield variables for the first and second cropping seasons.\u003c/p\u003e\n\u003cp\u003eDuring the first cropping season, yields of grain (1.26 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), cobs (0.3 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and stover (2.43 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in maize intercropped with \u003cem\u003eA. versicolor\u003c/em\u003e were significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) higher compared to that of maize intercropped with \u003cem\u003eA. harveyi\u003c/em\u003e as well as continuous cropping treatment (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Corresponding values for continuous cropping treatment were 0.29 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 0.06 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 1.06 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for yield of maize grain, cobs and stover respectively. This is equivalent to yield gain in maize grain, cobs and stover by 334.5%, 129.2% and 400% relative to continuous cropping treatment as a result of first season intercropping with \u003cem\u003eA. versicolor\u003c/em\u003e coppices respectively. The analogous increase in yield, relative to continuous cropping treatment, due to intercropping with \u003cem\u003eA. harveyi\u003c/em\u003e coppices were 155.2%, 40.6% and 233%. The results indicate superiority of \u003cem\u003eA. versicolor\u003c/em\u003e coppices over that of \u003cem\u003eA. harveyi\u003c/em\u003e in improving yields of the intercropped maize. However, this trend was reversed in the second cropping season (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e) where, though not statistically significant, intercropping with coppices of any of the studied tree species tended to suppress maize growth and yield.\u003c/p\u003e\n\u003cp\u003eDuring the second cropping season, there was no maize grain in any of the treatments due to sporadic rainfall. Despite the fact that there were no statistically significant differences, coppices of both tree species tended to suppress maize growth and yield in the second cropping season and the effect was similar for both tree species. Yields of maize stover, height and diameter growth were lower in intercropped maize relative to continuous cropping by 98\u0026ndash;98.7%, 14.8\u0026ndash;15.3% and 46.4\u0026ndash;81.0% respectively.\u003c/p\u003e\n\u003cp\u003eCoppice stump height and coppice thinning had no significant effects (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.5) on growth and yield of intercropped maize during the first cropping season, whereas their effects became significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in the second cropping season (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Effects of coppice stump cutting height on growth and yield of intercropped maize for two consecutive cropping seasons are presented (Fig.\u0026nbsp;4).\u003c/p\u003e\n\u003cp\u003eThough not significant, during the first cropping season, maize yields and growth tended to be higher in maize intercropped with coppices compared to continuous cropping treatment. The general trend was highest maize grain yield in coppices grown from stumps cut at the ground level. A similar pattern was observed for maize cob yields, whereas the pattern for stover yields was not clearly defined being highest in stumps cut at 90 cm above the ground, intermediate in stumps cut at the ground level and lowest in sumps cut at 30 cm from the ground level. During the first cropping season, maize grain yield ranged from 0.98 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for coppice stumps cut at 90 cm from the ground to 1.25 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for stumps cut at the ground level. This is in contrast to maize grain yield of 0.29 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e recorded in continuous cropping treatment. These results translate into an increase of maize grain yields ranging from 237.9% for maize intercropped with coppices from stumps cut at 90 cm from the ground to 331% for stumps cut at the ground level.\u003c/p\u003e\n\u003cp\u003eDuring the second cropping season, growth and yield of intercropped maize were reduced compared to the first cropping season but similar for all coppice stump height treatments; whereas they become significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) lower compared to continuous cropping treatment (Fig.\u0026nbsp;4). In that season, stover yields ranged from 0.02 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for both stumps cut at 30 cm and 90 cm from the ground to 0.04 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for stumps cut at the ground level. This was in comparison to stover yield of 1.04 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in continuous cropping treatment.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e shows effects of coppice thinning on growth and yield of intercropped maize for two successive cropping seasons. During the first cropping season, maize grain yield for maize intercropped with thinned coppice treatment (0.97 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) was slightly lower than that from no coppice thinning treatment (1.17 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) but about twice as much as grain yield of 0.29 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e from continuous cropping treatment (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). A similar pattern was observed for cobs and stover yields as well as maize plant growth. The similarities in maize growth and yield between coppice thinning and no thinning treatments continued during the second cropping season but became significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) lower than continuous cropping treatment (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eIn the second cropping season, maize stover yield was reduced in coppice thinning and no coppice thinning treatments at exactly the same rate of about 85% to 0.3 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e compared to stover yield of 2.03\u0026ndash;2.09 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in first cropping season. This was significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) lower than 1.04 Mg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e recorded in continuous cropping treatment.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003e4.1 Effects of tree fallow on soils\u003c/h2\u003e\n\u003cp\u003eThe OC content in 0\u0026ndash;20 cm soil depth found in this study is within the range of 0.41\u0026ndash;3.14% reported by [\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e] in the same area and 0.1 to 3.8% for the general miombo ecoregion [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e]. Soil assessment prior to establishment of coppice experiments demonstrated the potential of AF in utilizing the tested tree species to increase OC and OM within a short period of four years. These results corroborate well with results reported by [\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e] for rotational woodlots in Tanzania. Other studies elsewhere found no significant increase in OC and OM within three to five years of AF due to the fact that processes to increase soil OC, OM and soil fertility in general occurred slowly taking several years to detect [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]. The plausible explanation for the lack of significant AF trees effects on OC, OM and soil fertility in some studies could be nutrient removals associated with intensive fodder, fuel wood and poles extraction during tree fallow phase [\u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]. In contrast, in this study and studies by [\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e] and [\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e], AF trees were not harvested until the canopy closure. Interim intensive harvesting of fodder and fuel wood from AF systems are likely to influence OC and OM build-up since they tend to expose the soils to high temperature leading to loss of C through oxidation [\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e] as well as limiting foliar mass deposits on the ground surface.\u003c/p\u003e\n\u003cp\u003eThe low base (Ca, K, Mg and Na) content found in this study is a characteristic of highly weathered soils [\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e] typical of miombo woodlands [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e]. [\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e] found a significant relationship between ECEC of the soil and the amounts of clay and OC in the top soils. Thus, the low ECEC recorded in this study corresponds well to the low amounts of OM in the area. However, this study has shown the potential of the tested tree fallows in improving both OC and OM. After one cropping season, the amount of TN and OC recorded in coppice plots were significantly lower compared to continuous cropping plots. The most plausible explanation for this phenomenon is C loss to the atmosphere from the coppice plots. The magnitude of changes of SOM depends on the quantity and quality of prunings, soil type, system management, climate and duration of practice of the system [\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e]. Although the quantity of prunings added in coppice plots was higher than the continuous cropping plots, it is possible that the studied tree species produce prunings that are of high quality, in terms of low carbon - to - nitrogen (C:N) and lignin-to-nitrogen (L:N) ratios. Materials of this nature are likely to have negligible or little effects on soil C build up because C is returned to atmosphere via C evolution process. This proposition is supported by [\u003cspan class=\"CitationRef\"\u003e35\u003c/span\u003e] who found that addition of plant materials of high quality to soil led to C loss rather than accumulation. This was probably aggravated by soil exposure to high temperatures when coppices were still young leading to oxidation [\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e] and hence loss of C to the atmosphere. This can also serve to explain the high amounts of TN and OC in the tree fallow plots associated with differences in microclimate compared to coppiced plots. However, it is important to note that the quality of prunings from the studied tree species was not assessed due to unforeseen budget constraint, thus this aspect calls for further investigation.\u003c/p\u003e\n\u003cp\u003eLack of significant effects of tree coppice cutting height and coppice thinning treatments on soil chemical properties is probably due to the fact that foliar biomass as a result of these treatments were on the lower side. Improvement in soil nutrient status in AF is mainly through nutrients released from mineralization of prunings [\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e]. According to [\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e], nutrient contributions from AF systems are positively correlated to the amount of prunings added to the soil. In this study, foliar biomass ranged from 2.18 Mg ha\u003csup\u003e-1\u003c/sup\u003e in \u003cem\u003eA. versicolor\u003c/em\u003e to 2.86 Mg ha\u003csup\u003e-1\u003c/sup\u003e in \u003cem\u003eA. harveyi\u003c/em\u003e, which is lower compared to other AF studies that reported improved soil chemical properties. [\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e] reported improved soil chemical properties in AF system in which foliage yield ranged from 6.3 to 20.2 Mg ha\u003csup\u003e-1\u003c/sup\u003e. Besides yields of prunings, the effects of AF system on soil chemical properties can be influenced by nutrient contents and overall quality of the prunings such as C: N ratio that affects mineralization of nutrients [\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e]. This study did not assess these factors thus they require further investigation.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003e4.2 Effects on maize growth and yield\u003c/h2\u003e\n\u003cp\u003eThis study has demonstrated an increase in maize grain yield of intercropped maize of up to 100% during the first cropping season as compared to continuous cropping. This could be attributed to fertility improvement as a result of AF tree coppices related to various mechanisms such as biological N fixation, pumping up or retrieval of nutrients from lower soil horizons and interception of nutrients that would otherwise be lost through leaching and surface runoff and release of nutrients during litter and root decomposition [\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e]. Probably the increased maize yield in intercropped maize could be attributed to these mechanisms.\u003c/p\u003e\n\u003cp\u003eSignificant reduction in maize stover yields for maize intercropped with coppices could be attributed to combination of competition for light as result of shading, and competition for water resulting from developed tree root system [\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e]. These results are consistent with other simultaneous AF system studies [\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e]. In a semiarid area of Tanzania, [\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e] reported progressive reduction of yields of maize intercropped with Australian Acacias despite the fact that trees improved soil chemical properties. In Kenya, [\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e] reported decreased yield of maize intercropped with \u003cem\u003eGrevillea robusta\u003c/em\u003e after three years of intercropping. Similar results have been reported by [\u003cspan class=\"CitationRef\"\u003e39\u003c/span\u003e] in Kenya. It is important to note that the pattern of the effects of tree age on the nature and magnitude of competitiveness of AF trees varies with planting density (widely spaced trees taking longer to reduce crop yields) and is influenced by climate and species of crop involved [\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e41\u003c/span\u003e]. These aspects were not investigated in the present study, thus require further investigation.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIntercropping coppices of the studied trees with maize increased maize grain yield by 100% compared to continuous cropping treatment in the first cropping season suggesting soil amelioration effects of these tree species and the potential to boost livelihoods and achieve SDGs. However, in the second-year reduction in yields of maize intercropped with coppices of the studied tree species was observed indicating increasing competitive effects of the coppices of these tree species with age. Based on their positive effects on soil fertility, the studied tree species are recommended for on-farm planting for soil improvement. Planting these tree species in sequential AF systems such as improved fallow, intensive pruning of coppices or wider spacing in intercropping systems may reduce their competitive effects on the companion crops. The effects of AF system on soil chemical properties can be influenced by nutrient contents and overall quality of the prunings such as C: N ratio that affects mineralization of nutrients. Thus, these aspects require further investigation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of competing interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere are no conflicts of interest\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNorwegian Agency for Development Cooperation (NORAD) through the Programme for Agricultural and Natural Resources Transformation for Improved Livelihoods (PANTIL) of the Sokoine University of Agriculture (SUA), Tanzania supported this study. Department of Ecosystems and Conservation, College of Forestry, Wildlife and Tourism of SUA provided logistical support. Land for experiments and field assistance were provided by Maseyu villagers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVGV and SAOC conceptualized and designed the study; VGV investigated, curated and analysed data under the supervision of SAOC; SMA did additional data analysis and prepared the initial draft of the manuscript; VGV and SAOC improved the draft. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData used in this research is available upon official request from the main author after the date of publication.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNziguheba G, Palm CA, Berhe T, Denning G, Dicko A, Diouf O, Diru W, Flor R, Frimpong F, Harawa R, Kaya B, Manumbu E, McArthur J, Mutuo P, Ndiay, M, Niang A, Nkhoma P, Nyadzi G, Sachs J, Sullivan C, Teklu G, Tobe L, Sanchez PA. The African green revolution. Results from the millennium villages project. Adv Agron. 2010; 75\u0026ndash;115.\u003c/li\u003e\n\u003cli\u003eUN General Assembly. Sustainable Development Goals (SDGs): transforming our world: The 2030 agenda for sustainable development. New York: United Nations; 2015.\u003c/li\u003e\n\u003cli\u003eKopittke PM, Menzies NW, Wang P, McKenna BA, Lombi E. 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Agrofor Syst. 1997; 37:91\u0026ndash;109.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Agriculture, Productivity, Food security, Soil fertility, Yield, Tanzania","lastPublishedDoi":"10.21203/rs.3.rs-430132/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-430132/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAgriculture forms a backbone of many countries in sub-Saharan Africa (SSA) thus has the potential to contribute to achieving Sustainable Development Goals (SDGs). However, agriculture in the SSA is characterized by low production due to soil fertility depletion. Use of appropriate low input agricultural technologies may increase production and benefit smallholder farmers through increased productivity in already degraded land. A field experiment was established to assess tree coppice intercropping of \u003cem\u003eAlbizia harveyi\u003c/em\u003e and \u003cem\u003eAlbizia versicolor\u003c/em\u003e for soil fertility and maize yield improvements in Morogoro, Tanzania. Tree fallows of \u003cem\u003eA\u003c/em\u003e.\u003cem\u003e versicolor\u003c/em\u003e aged three years increased significantly soil organic Carbon, Calcium, Magnesium and Potassium. Yields of maize grain, cobs and stover in maize fields intercropped with \u003cem\u003eA\u003c/em\u003e.\u003cem\u003e versicolor\u003c/em\u003e were significantly higher than those with \u003cem\u003eA\u003c/em\u003e. \u003cem\u003eharveyi\u003c/em\u003e. Fields with continuous maize cropping had the least yields of grain, cobs and stover. The studied agroforestry tree species are recommended for rotational woodlots and short rotation coppice systems to enhance agricultural productivity for achieving SDGs.\u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Soil Nutrients and Maize Yields Responses to Agroforestry Tree Post-fallows Management in Tanzania","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-04-21 17:24:52","doi":"10.21203/rs.3.rs-430132/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"87e4d0ad-e180-4a38-8089-11b4ecbb2166","owner":[],"postedDate":"April 21st, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":3790538,"name":"Forestry"}],"tags":[],"updatedAt":"2021-04-30T02:44:05+00:00","versionOfRecord":[],"versionCreatedAt":"2021-04-21 17:24:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-430132","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-430132","identity":"rs-430132","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}