Short-term influence of cowpea crop and mineral fertilization on the spatial and temporal distribution of soil microbiological and chemical properties

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Soil fertility management is crucial for sustainable agriculture, particularly in the context of climate change. This study evaluates the short-term effects of cowpea and mineral fertilization on soil microbiological and chemical properties. Two field trials were conducted in 2021 and 2022 during the rainy season. Soil samples were collected at three depths (0–10 cm, 10–20 cm, and 20–30 cm) from plots where cowpea was grown either as a sole crop or with an additional application of 100 kg. ha − 1 of NPK. These samples were compared with those taken before sowing at the same depths. Results indicate minimal variation in soil characteristics across depths. However, bacterial abundance significantly decreased under sole cowpea cultivation and during the cropping season in 2022. A significant reduction in phosphorus levels was also observed in the sole cowpea plots (P = 0.0001). These findings suggest that short-term cowpea monoculture may contribute to phosphorus depletion and reduced bacterial charge, potentially impacting long-term soil fertility. Further studies are needed to assess the long-term sustainability of cowpea-based cropping systems and to explore potential mitigation strategies. Cultural practice Legume Soil bacteria Soil fertility Niger Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 9 Figure 10 Figure 11 Figure 12 Introduction In Niger, agriculture is based on cereal-based cropping systems, which are generally cultivated in association or rotation with legumes such as cowpea ( vigna unguiculata [L.] Walp) or groundnut ( Arachis hypogaea ). The majority of this agriculture is intended for household consumption (Hamidine et al. 2021 ) The most widespread cropping system is the millet-cowpea association, which occupies 67 to 87% of farmers depending on the region (Hamidine et al. 2021 ; Baoua et al. 2021 ). The introduction of legumes, particularly cowpeas, can be considered a food and income supplement and improve soil fertility, especially their nitrogen status through symbiotic nitrogen fixation (Gogoi et al. 2018 ). Therefore, their incorporation into cropping systems can reduce nitrogen fertilization (Foyer et al. 2016 ). According to Chaussod ( 1996 ), soil fertility comprises three components: chemical, physical, and biological. Biological fertility refers to the living fraction of organic matter, considering all soil microorganisms. Microorganisms serve as good indicators of soil organic status and play a significant role in organic matter decomposition (Abbott et al. 2007 ). The plant species is one of the factors shaping the community and bacterial abundance in the soil (Gao et al. 2021 ), with a positive effect from legumes (Ladygina et al. 2010). Legumes are an important nitrogen source for agroecosystems. Their decomposition is relatively faster (Murungu et al. 2011 ), thus they can stimulate microorganism proliferation (Barttlet-Ryser et al. 2005). However, according to Liu et al. ( 2020 ), continuous soybean cultivation leads to soil degradation and yield decline in the short term. Nevertheless, these effects could be mitigated by crop rotation or long-term continuous soybean cropping systems. The introduction of legumes into cropping systems in the short term is therefore not sufficient to improve soil productivity and food security. It is necessary to increase fertilizer or manure inputs to maintain soil phosphorus (Adams et al. 2020 ). Furthermore, these authors have shown that growing legumes alone does not increase either total phosphorus or available phosphorus, as plants, especially legumes, have a high demand for phosphorus (Gao et al. 2017 ). Indeed, several studies have shown that short-term mineral fertilization increases biomass and bacterial abundance. Historically, one of the methods for characterizing soil biological fertility is the enumeration of microorganisms. The objective of this study is to determine whether the presence of cowpea associated with mineral fertilization has a specific effect on the chemical and biological functioning of the soil. All conclusions will be based on the evolution of major mineral elements such as nitrogen, phosphorus, and potassium, as well as on the assessment of bacterial abundance over time and space. Materials and Methods Study Site The experimentation was conducted at the experimental site of the Faculty of Sciences and Techniques of Abdou Moumouni University in Niamey, Niger. This site is located between 13°30' North latitude and 2°05' East longitude, with an altitude of 204 m. The soil is a leached tropical ferruginous soil with a sandy texture. Two trials were conducted: The first trial was conducted during the rainy season of 2021, from July 11 to October 20, and the second trial conditions in 2022 from July to October always during the rainy season. Figure 1 shows the rainfall and temperature variation recorded during the two trials. 512.5 mm of rainfall was recorded over 33 days, and the average temperature was 17°C. Experimental details The experimental design is a randomized complete block with nine replications. The treatments consisted of factorial combinations of two fertilizer options: control and application of 100 kg/ha of NPK 15-15-15 at sowing. The elementary plots have an area of 6 m 2 (2.5 m × 2.4 m) and are spaced 1 m apart. The variety of cowpea used in this study has a 90-day cycle and is well appreciated by local populations for its dual-purpose use as grain and forage (Saidou et al. 2018 ). The variety includes CWS-F6-38-52. Cowpea was sown on July 11, seasons 2021 and 2022, at a rate of three seeds per hill, then thinned to two plants per hill 15 days after sowing. The spacing between hills was 30 cm with a row spacing of 50 cm. The 100 kg. ha − 1 of NPK was applied at sowing as the base fertilization. 2.3 Soil Sampling and Analysis of Soil Chemical Properties In this study, three treatments were compared for the chemical and microbiological analysis of soil samples. The three treatments are (i) bare soil before sowing (considered as a control to visualize the effect of the preceding cropping) (ii) bare soil from the plots where cowpea is cultivated alone, and (iii) bare soil from the plots where cowpea is cultivated + 100 kg. ha − 1 of NPK 15-15-15, the recommended dose for cowpea ( Vigna unguiculata L. Walp) (Kiari et al. 2015 ). Soil was sampled in 18 plots at three depths (0–10 cm; 10–20 cm; and 20–30 cm), specifically after harvesting during the two cropping seasons 2021, and 2022. In each plot, nine soil cores were collected using an auger, and a composite sample was formed for each depth. The soil samples collected were immediately transported to the laboratory and stored at 4°C in a refrigerator. Subsamples were then taken for chemical analyses and determination of bacterial abundance. The soil samples were analyzed for the following parameters: pH (H2O) using a pH meter (1:2.5 soil/water ratio); electrical conductivity using an EC meter; and total nitrogen using the Kjeldahl method (Houba et al. 1995 ). Assimilable phosphorus was extracted using the BRAY I method (Bray and Kurtz, 1945 ) with a solution of ammonium fluoride (NH4F) 0.03 M and hydrochloric acid 0.025 M, in a soil/solution extraction ratio of 1/7, and potassium was determined using the wet digestion method. 2.4 Bacterial Count The bacterial count was carried out according to the method of Bastide et al. ( 1986 ) It involved suspending 1g of dry and sieved soil from each prepared soil sample in 9 ml of sterile physiological water (NaCl 8.5g/l), representing a 10 − 1 dilution. After homogenization for 5 minutes on a vortex shaker, decimal dilutions were made in sterile water up to 10 − 5 . The bacterial enumeration was performed by spreading 0.1 ml of each of the last three dilutions on Petri dishes containing nutrient agar and then incubated at 37°C for 24 hours. After 24 hours of incubation, colonies of microorganisms were observed in the three Petri dishes macroscopically. The observed colonies displayed various characteristics (size, shape, color, opacity). To estimate the number of bacterial loads, the Petri dish is divided into eight (8) parts using a marker. Then, the number of colonies observed with the naked eye in one part is counted and multiplied by eight. The method used allows for the enumeration of viable microorganisms, i.e., those with the ability to grow on the culture media used under the provided growth conditions (temperature, oxygen, humidity, light, etc.). All the colonies present on the Petri dish are counted using a stereo microscope and a fiber optic light source. The surface counting technique is used to determine the number of units that can form a colony (CFU). According to this technique, each colony formed on the agar surface comes from a single bacterium (or mold) or an aggregate of bacteria (or molds). This method only considers viable microorganisms that can grow under the given growth conditions. If the number of colonies is very high, only a fraction of the surface is counted, and the result is multiplied by the inverse of that fraction to obtain the total count. 3 Data analysis For all collected data, the mean and standard deviation were calculated. After checking for normality using the Ryan-Joiner test and equality of variance using the Levene test, it was determined that the data did not follow a normal distribution. Therefore, the data underwent a log transformation. After transformation, two-way ANOVA followed by post-hoc multiple comparisons tests (using the emmeans method with Bonferroni correction) was performed to analyze the effect of two independent factors (depth and cropping season) and their interaction. A principal component analysis was performed combined with a biplot to explore the relationships between soil chemical properties and bacterial charge. Data analysis was performed using R software version 4.4.2. Results Variation in microbial charge based on depth and cropping season There was no significant effect of depth on bacterial charge (P = 0.215). However, bacterial charge varied highly significantly between seasons (2021, 2022) and samples collected before sowing, considered as the previous cropping period. The depth × sampling period interaction was not significant, implying that the effect of the sampling period was consistent across all depths. Post-hoc comparisons between sampling periods (Fig. 2 ) for each depth revealed the following: (i) At the 0–10 cm depth, bacterial load differed significantly between the pre-sowing period and the 2021 season. The 2021 and 2022 seasons also differed in bacterial abundance, whereas no difference was observed between the 2022 season and the pre-sowing period; (ii) At the 10–20 cm depth, no significant differences were detected between sampling periods (pre-sowing, 2021 season, and 2022 season); (ii) At the 20–30 cm depth, bacterial load varied significantly between the pre-sowing period and the 2022 season, as well as between the 2021 and 2022 seasons. However, no significant difference was observed between the pre-sowing period and the 2021 season. Variation in Microbial Number Based on Depth and Soil Occupation There is no significant difference regarding depth (P = 0.217). However, in terms of soil occupation, the difference is highly significant (P = 0.000618). The interaction between depth and soil occupation is not significant. Post-hoc comparisons of soil occupations (Fig. 3 ) for each depth show no significant difference at 0–10 cm and 10–20 cm depths. However, at 20–30 cm depth, the microbial charge varies significantly between pre-sowing and cowpea cultivated alone (P = 0.0246) and between cowpea + 100 kg. ha -1 NPK and cowpea cultivated alone (P = 0.0004). Similar values are observed between pre-sowing and cowpea with 100 kg/ha NPK, while cowpea cultivated alone appears to have the lowest microbial charge. Trends in soil physicochemical properties based on treatments, depth, and sampling period The results (Table 1 ) indicate that soil depth has no significant effect on soil pH, electrical conductivity, as well as major mineral elements: available phosphorus (AP), total Azote (TN), and potassium (K). The pH is acidic for all depths, with higher electrical conductivity at the 0–10 cm depth. Table 1 Effect of cowpea and mineral fertilization on soil chemical properties Variables pH (H20) CE dS/m − 1 AP mg/kg TN mg/kg K mg/kg 0_10 5,53 0,63 445,61 369,69 238,45 Depth (cm) 10_20 5,56 0,34 296,94 304,11 234,88 20_30 5,48 0,28 420,44 185,31 251,00 P value 0,37 0,95 0,45 0,78 0,7 Before sowing 5,22 0,40b 653,99a 257,61 242,66a Soil occupation Sole cowpea 6,11 0,31c 44,00c 211,15 238,50a Cowpea + NPK 5,44 0,50a 377,5b 359,83 123,70b P value 0,23 0,048 0,0001 0,085 0,0001 Before sowing 5,22b 0,40a 653,99a 257,61ab 242,67a Cropping season Season 2021 5,65a 0,44a 253,60b 303,40a 240,43a Season 2022 5,72a 0,36a 35,01c 185,30b 123,76b P value 0,002 0,07 0,0001 0,004 0,001 The numbers with the same letter(s) in the same column are not significantly different at the threshold of p < 0.05. EC: electrical conductivity, AP: assimilable phosphorus, TN: total nitrogen, K: potassium At the soil occupation level, all measured parameters were significantly affected except for total nitrogen and pH, where no difference was observed. However, the pH remains acidic. Total nitrogen is higher in cowpea + 100 kg. ha − 1 NPK (cowpea_NPK) (359.83 mg.kg − 1 ) and lower in before sowing with 257.61 mg.kg − 1 and sole cowpea (211.15 mg.kg − 1 ). Assimilable phosphorus is significantly higher before sowing (653.99 mg.kg − 1 ) than cowpea_NPK and sole cowpea on one hand, and the other hand, cowpea_NPK is significantly higher (377.5 mg.kg − 1 ) than sole cowpea (44 mg.kg − 1 ). At the cropping season level, during the 2021 and 2022 seasons, phosphorus levels showed a significant decrease compared to the pre-sowing period. Measured concentrations dropped from 235.6 mg.kg − 1 in 2021 to 35.01 mg.kg − 1 in 2022, contrasting with the elevated initial phosphorus levels observed before crop establishment (653.99 mg.kg − 1 ). As for total nitrogen, it showed a relative increase of 303.4 mg.kg − 1 for season 2021 and a decrease of 185.3 mg.kg − 1 for season 2022 compared to 257.61 mg.kg − 1 before sowing. Trend of bacterial charge based on soil chemical properties and depth Principal component analysis (PCA) combined with a biplot reveals clear relationships between soil chemical properties (nitrogen, potassium, pH, phosphorus, electrical conductivity) and bacterial load according to soil depth. The first principal component (Dim1), explaining 39.2% of the total variance, is strongly correlated with variables such as pH, phosphorus, potassium, and electrical conductivity (Fig. 4 ). The second component (Dim2, 16.5% of the variance) appears to be associated with nitrogen and bacterial charge. The PCA indicates that at 0–10 cm depth, bacterial charge is higher and is positively correlated with nitrogen. At 10–20 cm depth, bacterial charge is moderate, with a chemical composition that serves as a transition between the other two depths. At 20–30 cm depth, bacterial charge appears reduced. This layer is more associated with phosphorus, potassium, and electrical conductivity, but these factors seem to have less positive impact on bacterial load compared to nitrogen. Regarding pH, it seems to have an inverse effect. Samples with higher pH levels are positioned on the opposite side of the graph, suggesting a negative correlation with bacterial load. While phosphorus and potassium are present at deeper levels, they do not directly contribute to an increase in bacterial charge. Discussion This study reveals that short-term cowpea cultivation as a sole crop does not significantly improve soil microbiological and chemical properties. The bacterial abundance was notably lower under sole cowpea cropping, suggesting a possible nutrient depletion effect or seasonal influence. Similar trends have been reported in studies on continuous soybean cropping, where bacterial diversity and abundance declined due to nutrient exhaustion and root exudate changes (Tang et al. 2009 ; Yuan et al. 2021 ). Consecutive cowpea sole cultivation is therefore not conducive to bacterial proliferation. Additionally, the bacterial abundance is generally higher when NPK is applied to cowpea crops (Fig. 3 ). This is consistent with the findings of (Kanzawa et al. 1988; Belay et al. 2002 ; Wang et al. 2017 ), who showed that mineral fertilization increases bacterial numbers. However, repeated application of nitrogen fertilization can lead to a decrease or suppression of soil microorganisms (Lu et al; 2011 , Geisseler et al. 2014]) due to soil acidification from nitrogen (Liu et al. 2010 ). Consequently, an increase in pH could promote bacterial growth according to Gao et al. ( 2021 ), below a threshold of around 5 according to Geisler et al. (2014). The pH varied very little between 5 and 6 in this study (Table 1 ). Legumes are known to exert a significant influence on bacterial diversity and abundance through the root exudates they release into the soil (Zhou et al. 2017 ). In this study, cowpea did not significantly increase bacterial abundance at any depth, as sampling was done at the bare soil level and not at the rhizosphere level. For the major soil mineral elements, nitrogen content did not change at the soil occupation. This is consistent with the findings of Sainju et al. ( 2017 ), who found no change and even a decrease in total nitrogen due to legumes. In our study, cowpea was cut at ground level, leaving only the underground part during harvesting. However, most legume nitrogen is contained in the aboveground biomass and seeds, which are removed during harvest (Duboya et al. 2018). On the contrary, other studies have found an increase in total nitrogen (Zhou et al. 2017 ), possibly because they sampled soil at the rhizosphere level rather than at the bare soil level, as in our study. Bado et al. ( 2006 ) have also shown that mineral fertilization is supposed to increase symbiotic nitrogen fixation while increasing its availability in the soil through senescent leaves and cowpea roots. In our study, potassium significantly decreased in the plot where cowpea was grown alone, even though it is known to have a beneficial effect on symbiotic nitrogen fixation by legumes (Abdel-Wahab et al. 1985). However, phosphorus experienced a significant decrease in both the soil occupation and cropping season (Table 1 ). This suggests that neither crop residues nor root exudates due to the presence of cowpea during the season 2021 improved the soil's available phosphorus. This is likely due to the strong mobilization and absorption of phosphorus by legumes in general (Maltais-Landry, 2015 ). The observed phosphorus depletion corroborates findings by Adams et al. ( 2020 ), who highlighted that legumes have a high phosphorus demand, leading to reduced soil phosphorus availability when grown continuously without adequate fertilization. The application of NPK helped mitigate this depletion, reinforcing the importance of balanced nutrient management in legume-based systems. Cropping season variations significantly impacted bacterial abundance, with lower counts observed in the season 2022. This suggests that climate conditions, particularly moisture and temperature fluctuations, play a crucial role in microbial dynamics (Fierer et al. 2003 ). Future studies should consider long-term trials incorporating different preceding crops to evaluate cumulative effects on soil fertility and microbial charge. The PCA analysis shows that at 0–10 cm depth, bacterial charge is higher and positively correlated with nitrogen, suggesting that bacteria are favored by nutrient availability, particularly nitrogen. Our findings align with those of Hu et al. ( 2022 ), who demonstrated in a meta-analysis that nitrogen addition significantly increased fungal and bacterial necromass across different soil ecosystems. The low nitrogen availability could explain the slight decrease in bacterial charge observed between 10–20 cm and 20–30 cm depths. The blue ellipse highlights a greater variability among samples, which may indicate a higher heterogeneity in bacterial communities. Conclusion Our findings demonstrate that short-term cowpea cultivation leads to a decline in bacterial abundance and a significant reduction in soil phosphorus levels. The addition of NPK fertilizer mitigates some of these effects by maintaining higher bacterial counts and improving soil nutrient availability. However, our results also highlight that short-term cowpea cultivation is insufficient to enhance soil fertility sustainably. The observed decline in bacterial abundance may be partially attributed to cropping seasonal variations, suggesting that climatic factors also play a role in soil microbial dynamics. Declarations Acknowledgments: The authors acknowledge the dean authorities of the Faculty of Science and Technology at Abdou Moumouni University for providing the enabling environment for conducting the study. Author contributions: TDAK collected and analyzed the data and the first draft of the manuscript. AS and BY guided, supervised, and approved the project. MS participated in writing the manuscript. ASA and AS conducted the microbiological and chemical soil analyses. All authors read and approved the initial manuscript. Data availability : The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate Not applicable Funding: Partial financial support was received from Cowpea Square Project (https:// www. ccrp. org/ grants/ cowpea- square/) grant step 2 in Niger Republic. Consent for publication , Not applicable. Competing interests , the authors declare no competing interests. Clinical Trial : Not applicable References Hamidine I, Lawali S, Rabe MM, and Boukary BI (2021) Caractérisation des exploitations agricoles familiales productrices du mil et leur niveau de résilience dans la bande sud du Niger. J. Agric. Vet. Sci.14 (7): 05-16.DOI: 10.9790/2380-1407010516 Baoua I, Rabé MM, Murdock LL, and Dieudonne B (2021) Cowpea production constraints on smallholders’ farms in Maradi and Zinder regions, Niger. Crop. Prot. 142: 105533.https://doi.org/10.1016/j.cropro.2021.105533 Gogoi N, Baruah KK, Meena RS (2018) Grain Legumes: Impact on Soil Health andAgroecosystem. In: Meena, R., Das, A., Yadav, G., Lal, R. (eds) Legumes for Soil Health and Sustainable Management. Springer, Singapore. https://doi.org/10.1007/978-981-13-0253-4_16 Foyer, C.H., Lam, H.M & Nguyen, H.T et al. (2016) Neglecting legumes has compromised human health and sustainable food production. Nature Plants 2, 16112. https://doi.org/10.1038/nplants.2016.112 Chaussod, R (1996) La qualité biologique des sols : évaluation et implication. Etude et gestion des sols, 3 (4), 261-277. Abbott LK, Murphy DV (2007) What is soil biological fertility? In: Abbott LK and Murphy DV (eds) Soil biological fertility, A key to sustainable land use in Agriculture. Spinger, Dordrecht, Netherlands, pp 1–15. https://doi.org/10.1007/978-1-4020-6619-1 Gao H, Tian G, Khashi MR, & Wu F (2021) Cover Crop Species Composition Alters the Soil Bacterial Community in a Continuous Pepper Cropping System. Front. Microbiol. 12, 789034-789034. https://doi.org/10.3389/fmicb.2021.789034 Ladygina N, and Hedlund K (2010) Plant species influence microbial diversity and carbon allocation in the rhizosphere. Soil Biol. Biochem. 42, 162–168. https://doi.org/10.1016/j.soilbio.2009.10.009 Murungu FS, Chiduza C, Muchaonyerwa P, Mnkeni PNS (2011) Decomposition, nitrogen and phosphorus mineralization from winter-grown cover crop residues and suitability for a smallholder farming system in South Africa. Nutr. Cycl. Agroecosyst. 89, 115e123. https://doi.org/10.1007/s10705-010-9381-5 Bartelt-Ryser J, Joshi J, Schmid B, Brandl H, & Balser T (2005) Soil feedback of plant diversity on soil microbial communities and subsequent plant growth. Perspectives in Plant Ecology, Evolution and Systematics , 7 (1), 27-49. https://doi.org/10.1016/j.ppees.2004.11.002 Liu Z, Liu J, Yu Z, Yao Q, Li Y, Liang A & Wang G (2020) Long-term continuous cropping of soybean is comparable to crop rotation in mediating microbial abundance, diversity, and community composition. Soil Tillage Res . 197 , 104503. https://doi.org/10.1016/j.still.2019 Adams A M, Gillespie A W, Dhillon G S, Kar G, Minielly C, Koala S, & Peak D (2020) Long-term effects of integrated soil fertility management practices on soil chemical properties in the Sahel. Geoderma, 366 , 114207. https://doi.org/10.1016/j.geoderma.2020.114207 Gao D M, Zhou X G, Duan Y D, Fu X P, and Wu F Z ( 2017) Wheat cover crops promoted cucumber seedling growth by regulating soil nutrient resources or soil microbial communities. Plant Soil 418, 459–475. https://doi.org/10.1007/s11104-017-3307-9 Saidou A A, Issoufou Hassane B A, Salifou Jangorzo N, Ali A, Hassane S, Souley S, Saadou M (2018) Evaluation participative multilocale du compromis grains-fourrage de variétés de niébé double usage dans les zones Centre-sud et Ouest du Niger. Toulouse : INRA, p. 124-124. https://publications.cirad.fr/une_notice.php?dk=589228 Kiari A S, Maman NK, Fatouma S, Baoua I .2015. Fiche technique au Sahel. Institut National de Recherche Agronomique du Niger. 4 p. https://reca-niger.org/IMG/pdf/FT_Bandes_niebe_mil_INRAN_2015.pdf Houba V, Van der Lee J, Novozamsky I (1995) Soil analysis procedures; other procedures(soil and plant analysis, part 5B), vol 217, Department of Soil Science and Plant Nutrition,Wageningen Agricultural University. Bray R H, & Kurtz L T (1945) Determination of total, organic, and available forms of phosphorus in soils. Soil Sci. 59 (1), 39-46. https://doi.org/10.1097/00010694-194501000-00006 Bastide A, De Méo M, Andriantsoa M, Laget M, & Duménil G (1986) Isolement et sélection de souches d'actinomycètes productrices de substances antifongiques de structure non- polyénique. MIRCEN J. Appl. Microbiol Biotechnol. 2 , 453-466. https://doi.org/10.1007/BF00933368 Tang H, Xiao C, Ma J, Yu M, Li Y, Wang G, & Zhang L (2009) Prokaryotic diversity in continuous cropping and rotational cropping soybean soil. FEMS microbiology letters , 298 (2), 267-273. https://doi.org/10.1111/j.1574-6968.2009.01730.x Yuan M, Yu T, Shi Q, Han D, Yu K, Wang L, & Lian T (2021) Rhizosphere soil bacterial communities of continuous cropping-tolerant and sensitive soybean genotypes respond differently to long-term continuous cropping in mollisols. Front Microbiol . 12 , 729047. https://doi.org/10.3389/fmicb.2021.729047 Kanazawa S, Asakawa S, & Takai Y (1988) Effect of fertilizer and manure application on microbial numbers, biomass, and enzyme activities in volcanic ash soils: I. Microbial numbers and biomass carbon. Soil Sci. Plant Nutr. 34 (3), 429-439. https://doi.org/10.1080/00380768.1988.10415698 Belay A, Claassens A, & Wehner F C (2002) Effect of direct nitrogen and potassium and residual phosphorus fertilizers on soil chemical properties, microbial components, and maize yield under long-term crop rotation. Biol. Fertil. Soils. 35 (6), 420-427. https://doi.org/10.1007/s00374-002-0489-x Wang J, Song Y, Ma T, Raza W, Li J, Howland J G, & Shen Q (2017) Impacts of inorganic and organic fertilization treatments on bacterial and fungal communities in paddy soil. Appl. Soil Ecol. 112 , 42-50. https://doi.org/10.1016/j.apsoil.2017.01.005 Lu M, Yang Y, Luo Y, Fang C, Zhou X, Chen J, Yang X, Li B (2011) Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis. New Phytol. 189, 1040e1050. https://doi.org/10.1111/j.1469-8137.2010.03563.x Geisseler D, & Scow K M (2014) Long-term effects of mineral fertilizers on soil microorganisms–A review. Soil Biol. Biochem. 75 , 54-63. https://doi.org/10.1016/j.soilbio.2014.03.023 Liu E, Yan C, Mei X, He W, Bing S H, Ding L, & Fan T (2010). Long-term effect of chemical fertilizer, straw, and manure on soil chemical and biological properties in northwest China. Geoderma. 158 (3-4), 173-180. https://doi.org/10.1016/j.geoderma.2010.04.029 Zhou Y, Zhu H, Fu S, & Yao Q (2017) Variation in soil microbial community structure associated with different legume species is greater than that associated with different grass species. Front Microbiol. 8 , 1007. https://doi.org/10.3389/fmicb.2017.01007 Sainju U M, Singh H P, & Singh B P (2017). Cover crops for enriching soil carbon and nitrogen under bioenergy sorghum. Global Soil Sec. 181-192. https://doi.org/10.1007/978-3-319-43394-3_16 Dubova L, Alsina I, Ruža A, & Šenberga A (2018) Impact of faba bean (Vicia faba L.) cultivation on soil microbiological activity. Agro. Res. http://dx.doi.org/10.15159/ar.18.195 Bado BV, Bationo A, & Cescas M P (2006). Assessment of cowpea and groundnut contributions to soil fertility and succeeding sorghum yields in the Guinean savannah zone of Burkina Faso (West Africa). Biol. Fertil. Soils. 43 , 171-176. https://doi.org/10.1007/s00374-006-0076-7 Abdel-Wahab S (1985) Potassium nitrution and nitrogen fixation by nodulated legumes. Fertil. Res. 8 , 9–20. https://doi.org/10.1007/BF01048903 Maltais-Landry G (2015) Legumes have a greater effect on rhizosphere properties (pH, organic acids, and enzyme activity) but a smaller impact on soil P compared to other cover crops. Plant soil. 394 (1), 139-154. https://doi.org/10.1007/s11104-015-2518-1 Fierer N, Allen AS, Schimel JP, Holden PA (2003) Controls on microbial CO2 production: a comparison of surface and subsurface soil horizons. Global Change Biol. 9, 1322e1332. https://doi.org/10.1046/j.1365-2486.2003.00663.x Hu J, Huang C, Zhou S, Liu X, & Dijkstra FA (2022) Nitrogen addition increases microbial necromass in croplands and bacterial necromass in forests: A global meta-analysis. Soil Biol. Biochem. 165, 108500. https://doi.org/10.1016/j.soilbio.2021.108500 Additional Declarations No competing interests reported. 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Abdoul-Karim","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABDklEQVRIiWNgGAWjYDACCQYDBoaCBAYGZjAXSLI3AGkDCwJaDMBaGBvAWngOgLRIEKGFAaZFIgEijgvwz27e+JjHIE3evJ07/cHHNms5g5vPr274USDBwN/enYDVkjvHio15DHIM5xzm3dg4sy3d2OB2TtnNHqDDJM6c3YDVmhs5ZtI8BhWMM5h5Nzbzth1O3HA7J+0GD1CLgUQuVi3yUC32CC03z6Td/INHiwFES04iQssN9mO38dliCPSL4RyDtGSQlpkzzqUbS57JYbstYyDBg8svcrebNz54U5FsO4P/7IYPH8qs5fiOH392880fGzn+9l7s3scCeAzAJLHKQYD9ASmqR8EoGAWjYPgDAJlcY+CknSFDAAAAAElFTkSuQmCC","orcid":"","institution":"Abdou Moumouni University","correspondingAuthor":true,"prefix":"","firstName":"TOUDOU","middleName":"DAOUDA","lastName":"Abdoul-Karim","suffix":""},{"id":445559556,"identity":"bd7c6678-ad1f-4c6b-bef4-92be5ec4f65c","order_by":1,"name":"ALIO SANDA Abdel-Kader","email":"","orcid":"","institution":"Abdou Moumouni University","correspondingAuthor":false,"prefix":"","firstName":"ALIO","middleName":"SANDA","lastName":"Abdel-Kader","suffix":""},{"id":445559557,"identity":"81b24905-d0fd-4c6e-848c-e9aae0a68856","order_by":2,"name":"MOUSSA Soulé","email":"","orcid":"","institution":"Université Dan Dicko Dankoulodo de Maradi","correspondingAuthor":false,"prefix":"","firstName":"MOUSSA","middleName":"","lastName":"Soulé","suffix":""},{"id":445559558,"identity":"bf1853cc-75fd-458f-99a5-551d6072fe19","order_by":3,"name":"ABOUZEIDI Sareye","email":"","orcid":"","institution":"Abdou Moumouni University","correspondingAuthor":false,"prefix":"","firstName":"ABOUZEIDI","middleName":"","lastName":"Sareye","suffix":""},{"id":445559559,"identity":"4dbe4e3f-9283-446f-833c-9253b18ab940","order_by":4,"name":"ATTA Sanoussi","email":"","orcid":"","institution":"Abdou Moumouni University","correspondingAuthor":false,"prefix":"","firstName":"ATTA","middleName":"","lastName":"Sanoussi","suffix":""},{"id":445559560,"identity":"2fe69c06-1cb3-4462-9b53-e7ec94311e0d","order_by":5,"name":"BAKASSO Yacoubou","email":"","orcid":"","institution":"Abdou Moumouni University","correspondingAuthor":false,"prefix":"","firstName":"BAKASSO","middleName":"","lastName":"Yacoubou","suffix":""}],"badges":[],"createdAt":"2025-03-03 13:53:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6146869/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6146869/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":81181294,"identity":"a132ba96-71f5-495b-b54b-b489d166ff24","added_by":"auto","created_at":"2025-04-23 07:25:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":39830,"visible":true,"origin":"","legend":"\u003cp\u003eMonthly distribution of rainfall (mm) and variation in maximum and minimum temperature (°C) in Niamey in 2021 and 2022 (Toudou et al. 2024)\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/858d99122a13b13b400efe0a.png"},{"id":81180436,"identity":"bc49d7cb-122f-4c94-a251-fb8cd47daa01","added_by":"auto","created_at":"2025-04-23 07:17:11","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6374,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of soil depth and sampling period on bacterial charge\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/cd4b9d338d3b264a291db1c4.png"},{"id":81181494,"identity":"2aa00c8f-5a45-454d-be19-d78e7a3eedde","added_by":"auto","created_at":"2025-04-23 07:33:11","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":115885,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of soil depth and type of soil occupation on bacterial charge\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/ee67aa005abc593d5b861a1c.png"},{"id":81180441,"identity":"08a37c5e-db28-4e7f-b7df-9de05a79b9f8","added_by":"auto","created_at":"2025-04-23 07:17:11","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":11783,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRelationships Between soil chemical properties and Bacterial charge across soil depth (cm)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/06b7e1e204c88fec388bff2b.png"},{"id":81181295,"identity":"b9433448-152f-441d-adc7-855ae6e09b06","added_by":"auto","created_at":"2025-04-23 07:25:11","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":39830,"visible":true,"origin":"","legend":"\u003cp\u003eMonthly distribution of rainfall (mm) and variation in maximum and minimum temperature (°C) in Niamey in 2021 and 2022 (Toudou et al. 2024)\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/c14e428077f3ac5217deadc9.png"},{"id":81180442,"identity":"3cf94787-58c2-4ed3-8f50-ba898e3345d7","added_by":"auto","created_at":"2025-04-23 07:17:11","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":6374,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of soil depth and sampling period on bacterial charge\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/ec54089bb58e4b38d01ff4cb.png"},{"id":81181495,"identity":"a4b6b0cb-3c7a-403f-86f0-850ce2a50857","added_by":"auto","created_at":"2025-04-23 07:33:11","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":115885,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of soil depth and type of soil occupation on bacterial charge\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/ee050e53d30350dc57dcd61b.png"},{"id":81181298,"identity":"75efc397-0c10-42f2-a216-317cf57f438c","added_by":"auto","created_at":"2025-04-23 07:25:11","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":11783,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRelationships Between soil chemical properties and Bacterial charge across soil depth (cm)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/21442f651270ffe4490668c0.png"},{"id":82362347,"identity":"d297be98-50d6-4a25-a9b2-04293dcee589","added_by":"auto","created_at":"2025-05-09 12:01:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1228710,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6146869/v1/b972b25e-4e66-46c7-a6ae-78b1f43cc592.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Short-term influence of cowpea crop and mineral fertilization on the spatial and temporal distribution of soil microbiological and chemical properties","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn Niger, agriculture is based on cereal-based cropping systems, which are generally cultivated in association or rotation with legumes such as cowpea (\u003cem\u003evigna unguiculata\u003c/em\u003e [L.] Walp) or groundnut (\u003cem\u003eArachis hypogaea\u003c/em\u003e). The majority of this agriculture is intended for household consumption (Hamidine et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) The most widespread cropping system is the millet-cowpea association, which occupies 67 to 87% of farmers depending on the region (Hamidine et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Baoua et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe introduction of legumes, particularly cowpeas, can be considered a food and income supplement and improve soil fertility, especially their nitrogen status through symbiotic nitrogen fixation (Gogoi et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Therefore, their incorporation into cropping systems can reduce nitrogen fertilization (Foyer et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). According to Chaussod (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1996\u003c/span\u003e), soil fertility comprises three components: chemical, physical, and biological. Biological fertility refers to the living fraction of organic matter, considering all soil microorganisms. Microorganisms serve as good indicators of soil organic status and play a significant role in organic matter decomposition (Abbott et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe plant species is one of the factors shaping the community and bacterial abundance in the soil (Gao et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), with a positive effect from legumes (Ladygina et al. 2010). Legumes are an important nitrogen source for agroecosystems. Their decomposition is relatively faster (Murungu et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), thus they can stimulate microorganism proliferation (Barttlet-Ryser et al. 2005). However, according to Liu et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), continuous soybean cultivation leads to soil degradation and yield decline in the short term. Nevertheless, these effects could be mitigated by crop rotation or long-term continuous soybean cropping systems.\u003c/p\u003e \u003cp\u003eThe introduction of legumes into cropping systems in the short term is therefore not sufficient to improve soil productivity and food security. It is necessary to increase fertilizer or manure inputs to maintain soil phosphorus (Adams et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Furthermore, these authors have shown that growing legumes alone does not increase either total phosphorus or available phosphorus, as plants, especially legumes, have a high demand for phosphorus (Gao et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Indeed, several studies have shown that short-term mineral fertilization increases biomass and bacterial abundance. Historically, one of the methods for characterizing soil biological fertility is the enumeration of microorganisms.\u003c/p\u003e \u003cp\u003eThe objective of this study is to determine whether the presence of cowpea associated with mineral fertilization has a specific effect on the chemical and biological functioning of the soil. All conclusions will be based on the evolution of major mineral elements such as nitrogen, phosphorus, and potassium, as well as on the assessment of bacterial abundance over time and space.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Site\u003c/h2\u003e \u003cp\u003eThe experimentation was conducted at the experimental site of the Faculty of Sciences and Techniques of Abdou Moumouni University in Niamey, Niger. This site is located between 13\u0026deg;30' North latitude and 2\u0026deg;05' East longitude, with an altitude of 204 m. The soil is a leached tropical ferruginous soil with a sandy texture.\u003c/p\u003e \u003cp\u003eTwo trials were conducted:\u003c/p\u003e \u003cp\u003eThe first trial was conducted during the rainy season of 2021, from July 11 to October 20, and the second trial conditions in 2022 from July to October always during the rainy season.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the rainfall and temperature variation recorded during the two trials. 512.5 mm of rainfall was recorded over 33 days, and the average temperature was 17\u0026deg;C.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eExperimental details\u003c/h3\u003e\n\u003cp\u003eThe experimental design is a randomized complete block with nine replications. The treatments consisted of factorial combinations of two fertilizer options: control and application of 100 kg/ha of NPK 15-15-15 at sowing. The elementary plots have an area of 6 m\u003csup\u003e2\u003c/sup\u003e (2.5 m \u0026times; 2.4 m) and are spaced 1 m apart. The variety of cowpea used in this study has a 90-day cycle and is well appreciated by local populations for its dual-purpose use as grain and forage (Saidou et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The variety includes CWS-F6-38-52. Cowpea was sown on July 11, seasons 2021 and 2022, at a rate of three seeds per hill, then thinned to two plants per hill 15 days after sowing. The spacing between hills was 30 cm with a row spacing of 50 cm. The 100 kg. ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of NPK was applied at sowing as the base fertilization.\u003c/p\u003e\n\u003ch3\u003e2.3 Soil Sampling and Analysis of Soil Chemical Properties\u003c/h3\u003e\n\u003cp\u003eIn this study, three treatments were compared for the chemical and microbiological analysis of soil samples. The three treatments are (i) bare soil before sowing (considered as a control to visualize the effect of the preceding cropping) (ii) bare soil from the plots where cowpea is cultivated alone, and (iii) bare soil from the plots where cowpea is cultivated\u0026thinsp;+\u0026thinsp;100 kg. ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of NPK 15-15-15, the recommended dose for cowpea (\u003cem\u003eVigna unguiculata\u003c/em\u003e L. Walp) (Kiari et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Soil was sampled in 18 plots at three depths (0\u0026ndash;10 cm; 10\u0026ndash;20 cm; and 20\u0026ndash;30 cm), specifically after harvesting during the two cropping seasons 2021, and 2022. In each plot, nine soil cores were collected using an auger, and a composite sample was formed for each depth. The soil samples collected were immediately transported to the laboratory and stored at 4\u0026deg;C in a refrigerator. Subsamples were then taken for chemical analyses and determination of bacterial abundance.\u003c/p\u003e \u003cp\u003eThe soil samples were analyzed for the following parameters: pH (H2O) using a pH meter (1:2.5 soil/water ratio); electrical conductivity using an EC meter; and total nitrogen using the Kjeldahl method (Houba et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). Assimilable phosphorus was extracted using the BRAY I method (Bray and Kurtz, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1945\u003c/span\u003e) with a solution of ammonium fluoride (NH4F) 0.03 M and hydrochloric acid 0.025 M, in a soil/solution extraction ratio of 1/7, and potassium was determined using the wet digestion method.\u003c/p\u003e\n\u003ch3\u003e2.4 Bacterial Count\u003c/h3\u003e\n\u003cp\u003eThe bacterial count was carried out according to the method of Bastide et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1986\u003c/span\u003e) It involved suspending 1g of dry and sieved soil from each prepared soil sample in 9 ml of sterile physiological water (NaCl 8.5g/l), representing a 10\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e dilution. After homogenization for 5 minutes on a vortex shaker, decimal dilutions were made in sterile water up to 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe bacterial enumeration was performed by spreading 0.1 ml of each of the last three dilutions on Petri dishes containing nutrient agar and then incubated at 37\u0026deg;C for 24 hours. After 24 hours of incubation, colonies of microorganisms were observed in the three Petri dishes macroscopically. The observed colonies displayed various characteristics (size, shape, color, opacity).\u003c/p\u003e \u003cp\u003eTo estimate the number of bacterial loads, the Petri dish is divided into eight (8) parts using a marker. Then, the number of colonies observed with the naked eye in one part is counted and multiplied by eight. The method used allows for the enumeration of viable microorganisms, i.e., those with the ability to grow on the culture media used under the provided growth conditions (temperature, oxygen, humidity, light, etc.).\u003c/p\u003e \u003cp\u003eAll the colonies present on the Petri dish are counted using a stereo microscope and a fiber optic light source. The surface counting technique is used to determine the number of units that can form a colony (CFU). According to this technique, each colony formed on the agar surface comes from a single bacterium (or mold) or an aggregate of bacteria (or molds). This method only considers viable microorganisms that can grow under the given growth conditions. If the number of colonies is very high, only a fraction of the surface is counted, and the result is multiplied by the inverse of that fraction to obtain the total count.\u003c/p\u003e\n\u003ch3\u003e3 Data analysis\u003c/h3\u003e\n\u003cp\u003eFor all collected data, the mean and standard deviation were calculated. After checking for normality using the Ryan-Joiner test and equality of variance using the Levene test, it was determined that the data did not follow a normal distribution. Therefore, the data underwent a log transformation. After transformation, two-way ANOVA followed by post-hoc multiple comparisons tests (using the emmeans method with Bonferroni correction) was performed to analyze the effect of two independent factors (depth and cropping season) and their interaction. A principal component analysis was performed combined with a biplot to explore the relationships between soil chemical properties and bacterial charge. Data analysis was performed using R software version 4.4.2.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eVariation in microbial charge based on depth and cropping season\u003c/h2\u003e \u003cp\u003eThere was no significant effect of depth on bacterial charge (P\u0026thinsp;=\u0026thinsp;0.215). However, bacterial charge varied highly significantly between seasons (2021, 2022) and samples collected before sowing, considered as the previous cropping period. The depth \u0026times; sampling period interaction was not significant, implying that the effect of the sampling period was consistent across all depths. Post-hoc comparisons between sampling periods (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) for each depth revealed the following: (i) At the 0\u0026ndash;10 cm depth, bacterial load differed significantly between the pre-sowing period and the 2021 season. The 2021 and 2022 seasons also differed in bacterial abundance, whereas no difference was observed between the 2022 season and the pre-sowing period; (ii) At the 10\u0026ndash;20 cm depth, no significant differences were detected between sampling periods (pre-sowing, 2021 season, and 2022 season); (ii) At the 20\u0026ndash;30 cm depth, bacterial load varied significantly between the pre-sowing period and the 2022 season, as well as between the 2021 and 2022 seasons. However, no significant difference was observed between the pre-sowing period and the 2021 season.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eVariation in Microbial Number Based on Depth and Soil Occupation\u003c/h3\u003e\n\u003cp\u003eThere is no significant difference regarding depth (P\u0026thinsp;=\u0026thinsp;0.217). However, in terms of soil occupation, the difference is highly significant (P\u0026thinsp;=\u0026thinsp;0.000618). The interaction between depth and soil occupation is not significant. Post-hoc comparisons of soil occupations (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) for each depth show no significant difference at 0\u0026ndash;10 cm and 10\u0026ndash;20 cm depths. However, at 20\u0026ndash;30 cm depth, the microbial charge varies significantly between pre-sowing and cowpea cultivated alone (P\u0026thinsp;=\u0026thinsp;0.0246) and between cowpea\u0026thinsp;+\u0026thinsp;100 kg. ha\u003csup\u003e-1\u003c/sup\u003e NPK and cowpea cultivated alone (P\u0026thinsp;=\u0026thinsp;0.0004). Similar values are observed between pre-sowing and cowpea with 100 kg/ha NPK, while cowpea cultivated alone appears to have the lowest microbial charge.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eTrends in soil physicochemical properties based on treatments, depth, and sampling period\u003c/h2\u003e \u003cp\u003eThe results (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) indicate that soil depth has no significant effect on soil pH, electrical conductivity, as well as major mineral elements: available phosphorus (AP), total Azote (TN), and potassium (K). The pH is acidic for all depths, with higher electrical conductivity at the 0\u0026ndash;10 cm depth.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffect of cowpea and mineral fertilization on soil chemical properties\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003epH (H20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCE dS/m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAP mg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTN mg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eK mg/kg\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0_10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e445,61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e369,69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e238,45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDepth (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10_20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e296,94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e304,11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e234,88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20_30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e420,44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e185,31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e251,00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0,37\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,95\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,45\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0,78\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0,7\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore sowing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,40b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e653,99a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e257,61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e242,66a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoil occupation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSole cowpea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6,11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,31c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e44,00c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e211,15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e238,50a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCowpea\u0026thinsp;+\u0026thinsp;NPK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,50a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e377,5b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e359,83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e123,70b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0,23\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,048\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0,085\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore sowing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,22b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,40a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e653,99a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e257,61ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e242,67a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCropping season\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSeason 2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,65a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,44a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e253,60b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e303,40a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e240,43a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSeason 2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,72a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0,36a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e35,01c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e185,30b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e123,76b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0,002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,07\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0,004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eThe numbers with the same letter(s) in the same column are not significantly different at the threshold of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. EC: electrical conductivity, AP: assimilable phosphorus, TN: total nitrogen, K: potassium\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAt the soil occupation level, all measured parameters were significantly affected except for total nitrogen and pH, where no difference was observed. However, the pH remains acidic. Total nitrogen is higher in cowpea\u0026thinsp;+\u0026thinsp;100 kg. ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e NPK (cowpea_NPK) (359.83 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and lower in before sowing with 257.61 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and sole cowpea (211.15 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e).\u003c/p\u003e \u003cp\u003eAssimilable phosphorus is significantly higher before sowing (653.99 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) than cowpea_NPK and sole cowpea on one hand, and the other hand, cowpea_NPK is significantly higher (377.5 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) than sole cowpea (44 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e).\u003c/p\u003e \u003cp\u003eAt the cropping season level, during the 2021 and 2022 seasons, phosphorus levels showed a significant decrease compared to the pre-sowing period. Measured concentrations dropped from 235.6 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in 2021 to 35.01 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in 2022, contrasting with the elevated initial phosphorus levels observed before crop establishment (653.99 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). As for total nitrogen, it showed a relative increase of 303.4 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for season 2021 and a decrease of 185.3 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for season 2022 compared to 257.61 mg.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e before sowing.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eTrend of bacterial charge based on soil chemical properties and depth\u003c/h2\u003e \u003cp\u003ePrincipal component analysis (PCA) combined with a biplot reveals clear relationships between soil chemical properties (nitrogen, potassium, pH, phosphorus, electrical conductivity) and bacterial load according to soil depth. The first principal component (Dim1), explaining 39.2% of the total variance, is strongly correlated with variables such as pH, phosphorus, potassium, and electrical conductivity (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The second component (Dim2, 16.5% of the variance) appears to be associated with nitrogen and bacterial charge.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe PCA indicates that at 0\u0026ndash;10 cm depth, bacterial charge is higher and is positively correlated with nitrogen. At 10\u0026ndash;20 cm depth, bacterial charge is moderate, with a chemical composition that serves as a transition between the other two depths. At 20\u0026ndash;30 cm depth, bacterial charge appears reduced. This layer is more associated with phosphorus, potassium, and electrical conductivity, but these factors seem to have less positive impact on bacterial load compared to nitrogen.\u003c/p\u003e \u003cp\u003eRegarding pH, it seems to have an inverse effect. Samples with higher pH levels are positioned on the opposite side of the graph, suggesting a negative correlation with bacterial load. While phosphorus and potassium are present at deeper levels, they do not directly contribute to an increase in bacterial charge.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study reveals that short-term cowpea cultivation as a sole crop does not significantly improve soil microbiological and chemical properties. The bacterial abundance was notably lower under sole cowpea cropping, suggesting a possible nutrient depletion effect or seasonal influence. Similar trends have been reported in studies on continuous soybean cropping, where bacterial diversity and abundance declined due to nutrient exhaustion and root exudate changes (Tang et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Yuan et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Consecutive cowpea sole cultivation is therefore not conducive to bacterial proliferation. Additionally, the bacterial abundance is generally higher when NPK is applied to cowpea crops (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This is consistent with the findings of (Kanzawa et al. 1988; Belay et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Wang et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), who showed that mineral fertilization increases bacterial numbers. However, repeated application of nitrogen fertilization can lead to a decrease or suppression of soil microorganisms (Lu et al; \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2011\u003c/span\u003e, Geisseler et al. 2014]) due to soil acidification from nitrogen (Liu et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Consequently, an increase in pH could promote bacterial growth according to Gao et al. (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), below a threshold of around 5 according to Geisler et al. (2014). The pH varied very little between 5 and 6 in this study (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Legumes are known to exert a significant influence on bacterial diversity and abundance through the root exudates they release into the soil (Zhou et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In this study, cowpea did not significantly increase bacterial abundance at any depth, as sampling was done at the bare soil level and not at the rhizosphere level.\u003c/p\u003e \u003cp\u003eFor the major soil mineral elements, nitrogen content did not change at the soil occupation. This is consistent with the findings of Sainju et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), who found no change and even a decrease in total nitrogen due to legumes. In our study, cowpea was cut at ground level, leaving only the underground part during harvesting. However, most legume nitrogen is contained in the aboveground biomass and seeds, which are removed during harvest (Duboya et al. 2018). On the contrary, other studies have found an increase in total nitrogen (Zhou et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), possibly because they sampled soil at the rhizosphere level rather than at the bare soil level, as in our study. Bado et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) have also shown that mineral fertilization is supposed to increase symbiotic nitrogen fixation while increasing its availability in the soil through senescent leaves and cowpea roots. In our study, potassium significantly decreased in the plot where cowpea was grown alone, even though it is known to have a beneficial effect on symbiotic nitrogen fixation by legumes (Abdel-Wahab et al. 1985). However, phosphorus experienced a significant decrease in both the soil occupation and cropping season (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This suggests that neither crop residues nor root exudates due to the presence of cowpea during the season 2021 improved the soil's available phosphorus. This is likely due to the strong mobilization and absorption of phosphorus by legumes in general (Maltais-Landry, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). The observed phosphorus depletion corroborates findings by Adams et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), who highlighted that legumes have a high phosphorus demand, leading to reduced soil phosphorus availability when grown continuously without adequate fertilization. The application of NPK helped mitigate this depletion, reinforcing the importance of balanced nutrient management in legume-based systems.\u003c/p\u003e \u003cp\u003eCropping season variations significantly impacted bacterial abundance, with lower counts observed in the season 2022. This suggests that climate conditions, particularly moisture and temperature fluctuations, play a crucial role in microbial dynamics (Fierer et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Future studies should consider long-term trials incorporating different preceding crops to evaluate cumulative effects on soil fertility and microbial charge.\u003c/p\u003e \u003cp\u003eThe PCA analysis shows that at 0\u0026ndash;10 cm depth, bacterial charge is higher and positively correlated with nitrogen, suggesting that bacteria are favored by nutrient availability, particularly nitrogen. Our findings align with those of Hu et al. (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), who demonstrated in a meta-analysis that nitrogen addition significantly increased fungal and bacterial necromass across different soil ecosystems.\u003c/p\u003e \u003cp\u003eThe low nitrogen availability could explain the slight decrease in bacterial charge observed between 10\u0026ndash;20 cm and 20\u0026ndash;30 cm depths.\u003c/p\u003e \u003cp\u003eThe blue ellipse highlights a greater variability among samples, which may indicate a higher heterogeneity in bacterial communities.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOur findings demonstrate that short-term cowpea cultivation leads to a decline in bacterial abundance and a significant reduction in soil phosphorus levels. The addition of NPK fertilizer mitigates some of these effects by maintaining higher bacterial counts and improving soil nutrient availability. However, our results also highlight that short-term cowpea cultivation is insufficient to enhance soil fertility sustainably. The observed decline in bacterial abundance may be partially attributed to cropping seasonal variations, suggesting that climatic factors also play a role in soil microbial dynamics.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e The authors acknowledge the dean authorities of the Faculty of Science and Technology at Abdou Moumouni University for providing the enabling environment for conducting the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u0026nbsp;\u003c/strong\u003eTDAK collected and analyzed the data and the first draft of the manuscript. \u0026nbsp;AS and BY guided, supervised, and approved the project. MS participated in writing the manuscript. ASA and AS conducted the microbiological and chemical soil analyses. \u0026nbsp; All authors read and approved the initial manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e Partial financial support was received from Cowpea Square Project (https:// www. ccrp. org/ grants/ cowpea- square/) grant step 2 in Niger Republic.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e, Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e, the authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial :\u003c/strong\u003e Not applicable\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHamidine I, Lawali S, Rabe MM, and Boukary BI (2021) Caract\u0026eacute;risation des exploitations agricoles familiales productrices du mil et leur niveau de r\u0026eacute;silience dans la bande sud du Niger. J. Agric. Vet. Sci.14 (7): 05-16.DOI: \u003cu\u003e10.9790/2380-1407010516\u003c/u\u003e\u003c/li\u003e\n\u003cli\u003eBaoua I, Rab\u0026eacute; MM, Murdock LL, and Dieudonne B (2021) Cowpea production constraints on smallholders\u0026rsquo; farms in Maradi and Zinder regions, Niger. Crop. Prot. 142: 105533.https://doi.org/10.1016/j.cropro.2021.105533\u003c/li\u003e\n\u003cli\u003eGogoi N, Baruah KK, Meena RS (2018) Grain Legumes: Impact on Soil Health andAgroecosystem. In: Meena, R., Das, A., Yadav, G., Lal, R. (eds) Legumes for Soil Health and Sustainable Management. Springer, Singapore. https://doi.org/10.1007/978-981-13-0253-4_16\u003c/li\u003e\n\u003cli\u003eFoyer, C.H., Lam, H.M \u0026amp; Nguyen, H.T et al. (2016) Neglecting legumes has compromised human health and sustainable food production. Nature Plants 2, 16112. https://doi.org/10.1038/nplants.2016.112\u003c/li\u003e\n\u003cli\u003eChaussod, R (1996) La qualit\u0026eacute; biologique des sols : \u0026eacute;valuation et implication. Etude et gestion des sols, 3 (4), 261-277.\u003c/li\u003e\n\u003cli\u003eAbbott LK, Murphy DV (2007) What is soil biological fertility? In: Abbott LK and Murphy DV (eds) Soil biological fertility, A key to sustainable land use in Agriculture. Spinger, Dordrecht, Netherlands, pp 1\u0026ndash;15. https://doi.org/10.1007/978-1-4020-6619-1\u003c/li\u003e\n\u003cli\u003eGao H, Tian G, Khashi MR, \u0026amp; Wu F (2021) Cover Crop Species Composition Alters the Soil Bacterial Community in a Continuous Pepper Cropping System. Front. Microbiol. 12, 789034-789034. https://doi.org/10.3389/fmicb.2021.789034\u003c/li\u003e\n\u003cli\u003eLadygina N, and Hedlund K (2010) Plant species influence microbial diversity and carbon allocation in the rhizosphere. Soil Biol. Biochem. 42, 162\u0026ndash;168. https://doi.org/10.1016/j.soilbio.2009.10.009\u003c/li\u003e\n\u003cli\u003eMurungu FS, Chiduza C, Muchaonyerwa P, Mnkeni PNS (2011) Decomposition, nitrogen and phosphorus mineralization from winter-grown cover crop residues and suitability for a smallholder farming system in South Africa. Nutr. Cycl. Agroecosyst. 89, 115e123. https://doi.org/10.1007/s10705-010-9381-5\u003c/li\u003e\n\u003cli\u003eBartelt-Ryser J, Joshi J, Schmid B, Brandl H, \u0026amp; Balser T (2005) Soil feedback of plant diversity on soil microbial communities and subsequent plant growth. \u003cem\u003ePerspectives in Plant Ecology, Evolution and Systematics\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e(1), 27-49. https://doi.org/10.1016/j.ppees.2004.11.002\u003c/li\u003e\n\u003cli\u003eLiu Z, Liu J, Yu Z, Yao Q, Li Y, Liang A \u0026amp; Wang G (2020) Long-term continuous cropping of soybean is comparable to crop rotation in mediating microbial abundance, diversity, and community composition. Soil Tillage Res\u003cem\u003e.\u003c/em\u003e \u003cem\u003e197\u003c/em\u003e, 104503. https://doi.org/10.1016/j.still.2019\u003c/li\u003e\n\u003cli\u003eAdams A M, Gillespie A W, Dhillon G S, Kar G, Minielly C, Koala S, \u0026amp; Peak D (2020) Long-term effects of integrated soil fertility management practices on soil chemical properties in the Sahel. Geoderma, \u003cem\u003e366\u003c/em\u003e, 114207. https://doi.org/10.1016/j.geoderma.2020.114207\u003c/li\u003e\n\u003cli\u003eGao D M, Zhou X G, Duan Y D, Fu X P, and Wu F Z ( 2017) Wheat cover crops promoted cucumber seedling growth by regulating soil nutrient resources or soil microbial communities. Plant Soil 418, 459\u0026ndash;475. https://doi.org/10.1007/s11104-017-3307-9\u003c/li\u003e\n\u003cli\u003eSaidou A A, Issoufou Hassane B A, Salifou Jangorzo N, Ali A, Hassane S, Souley S, Saadou M (2018) Evaluation participative multilocale du compromis grains-fourrage de vari\u0026eacute;t\u0026eacute;s de ni\u0026eacute;b\u0026eacute; double usage dans les zones Centre-sud et Ouest du Niger. Toulouse : INRA, p. 124-124. https://publications.cirad.fr/une_notice.php?dk=589228\u003c/li\u003e\n\u003cli\u003eKiari A S, Maman NK, Fatouma S, Baoua I .2015. Fiche technique au Sahel. Institut National de Recherche Agronomique du Niger. 4 p. https://reca-niger.org/IMG/pdf/FT_Bandes_niebe_mil_INRAN_2015.pdf\u003c/li\u003e\n\u003cli\u003eHouba V, Van der Lee J, Novozamsky I (1995) Soil analysis procedures; other procedures(soil and plant analysis, part 5B), vol 217, Department of Soil Science and Plant Nutrition,Wageningen Agricultural University.\u003c/li\u003e\n\u003cli\u003eBray R H, \u0026amp; Kurtz L T (1945) Determination of total, organic, and available forms of phosphorus in soils. Soil Sci. \u003cem\u003e59\u003c/em\u003e(1), 39-46. https://doi.org/10.1097/00010694-194501000-00006 \u003c/li\u003e\n\u003cli\u003eBastide A, De M\u0026eacute;o M, Andriantsoa M, Laget M, \u0026amp; Dum\u0026eacute;nil G (1986) Isolement et s\u0026eacute;lection de souches d\u0026apos;actinomyc\u0026egrave;tes productrices de substances antifongiques de structure non- poly\u0026eacute;nique. MIRCEN J. Appl. Microbiol Biotechnol. \u003cem\u003e2\u003c/em\u003e, 453-466. https://doi.org/10.1007/BF00933368\u003c/li\u003e\n\u003cli\u003eTang H, Xiao C, Ma J, Yu M, Li Y, Wang G, \u0026amp; Zhang L (2009) Prokaryotic diversity in continuous cropping and rotational cropping soybean soil. \u003cem\u003eFEMS microbiology letters\u003c/em\u003e, \u003cem\u003e298\u003c/em\u003e(2), 267-273. https://doi.org/10.1111/j.1574-6968.2009.01730.x\u003c/li\u003e\n\u003cli\u003eYuan M, Yu T, Shi Q, Han D, Yu K, Wang L, \u0026amp; Lian T (2021) Rhizosphere soil bacterial communities of continuous cropping-tolerant and sensitive soybean genotypes respond differently to long-term continuous cropping in mollisols. Front Microbiol\u003cem\u003e.\u003c/em\u003e \u003cem\u003e12\u003c/em\u003e, 729047. https://doi.org/10.3389/fmicb.2021.729047 \u003c/li\u003e\n\u003cli\u003eKanazawa S, Asakawa S, \u0026amp; Takai Y (1988) Effect of fertilizer and manure application on microbial numbers, biomass, and enzyme activities in volcanic ash soils: I. Microbial numbers and biomass carbon. Soil Sci. Plant Nutr. \u003cem\u003e34\u003c/em\u003e(3), 429-439. https://doi.org/10.1080/00380768.1988.10415698\u003c/li\u003e\n\u003cli\u003eBelay A, Claassens A, \u0026amp; Wehner F C (2002) Effect of direct nitrogen and potassium and residual phosphorus fertilizers on soil chemical properties, microbial components, and maize yield under long-term crop rotation. Biol. Fertil. Soils. \u003cem\u003e35\u003c/em\u003e(6), 420-427. https://doi.org/10.1007/s00374-002-0489-x\u003c/li\u003e\n\u003cli\u003eWang J, Song Y, Ma T, Raza W, Li J, Howland J G, \u0026amp; Shen Q (2017) Impacts of inorganic and organic fertilization treatments on bacterial and fungal communities in paddy soil. Appl. Soil Ecol. \u003cem\u003e112\u003c/em\u003e, 42-50. https://doi.org/10.1016/j.apsoil.2017.01.005\u003c/li\u003e\n\u003cli\u003eLu M, Yang Y, Luo Y, Fang C, Zhou X, Chen J, Yang X, Li B (2011) Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis. New Phytol. 189, 1040e1050. \u003cstrong\u003ehttps://doi.org/10.1111/j.1469-8137.2010.03563.x\u003c/strong\u003e\u003c/li\u003e\n\u003cli\u003eGeisseler D, \u0026amp; Scow K M (2014) Long-term effects of mineral fertilizers on soil microorganisms\u0026ndash;A review. Soil Biol. Biochem. \u003cem\u003e75\u003c/em\u003e, 54-63. https://doi.org/10.1016/j.soilbio.2014.03.023\u003c/li\u003e\n\u003cli\u003eLiu E, Yan C, Mei X, He W, Bing S H, Ding L, \u0026amp; Fan T (2010). Long-term effect of chemical fertilizer, straw, and manure on soil chemical and biological properties in northwest China. Geoderma. \u003cem\u003e158\u003c/em\u003e(3-4), 173-180. https://doi.org/10.1016/j.geoderma.2010.04.029\u003c/li\u003e\n\u003cli\u003eZhou Y, Zhu H, Fu S, \u0026amp; Yao Q (2017) Variation in soil microbial community structure associated with different legume species is greater than that associated with different grass species. Front Microbiol. \u003cem\u003e8\u003c/em\u003e, 1007. https://doi.org/10.3389/fmicb.2017.01007\u003c/li\u003e\n\u003cli\u003eSainju U M, Singh H P, \u0026amp; Singh B P (2017). Cover crops for enriching soil carbon and nitrogen under bioenergy sorghum. Global Soil Sec. 181-192. https://doi.org/10.1007/978-3-319-43394-3_16\u003c/li\u003e\n\u003cli\u003eDubova L, Alsina I, Ruža A, \u0026amp; \u0026Scaron;enberga A (2018) Impact of faba bean (Vicia faba L.) cultivation on soil microbiological activity. Agro. Res. http://dx.doi.org/10.15159/ar.18.195\u003c/li\u003e\n\u003cli\u003eBado BV, Bationo A, \u0026amp; Cescas M P (2006). Assessment of cowpea and groundnut contributions to soil fertility and succeeding sorghum yields in the Guinean savannah zone of Burkina Faso (West Africa). Biol. Fertil. Soils. \u003cem\u003e43\u003c/em\u003e, 171-176. https://doi.org/10.1007/s00374-006-0076-7\u003c/li\u003e\n\u003cli\u003eAbdel-Wahab S (1985) Potassium nitrution and nitrogen fixation by nodulated legumes. Fertil. Res. \u003cstrong\u003e8\u003c/strong\u003e, 9\u0026ndash;20. https://doi.org/10.1007/BF01048903\u003c/li\u003e\n\u003cli\u003eMaltais-Landry G (2015) Legumes have a greater effect on rhizosphere properties (pH, organic acids, and enzyme activity) but a smaller impact on soil P compared to other cover crops. Plant soil. \u003cem\u003e394\u003c/em\u003e(1), 139-154. https://doi.org/10.1007/s11104-015-2518-1\u003c/li\u003e\n\u003cli\u003eFierer N, Allen AS, Schimel JP, Holden PA (2003) Controls on microbial CO2 production: a comparison of surface and subsurface soil horizons. Global Change Biol. 9, 1322e1332. https://doi.org/10.1046/j.1365-2486.2003.00663.x\u003c/li\u003e\n\u003cli\u003eHu J, Huang C, Zhou S, Liu X, \u0026amp; Dijkstra FA (2022) Nitrogen addition increases microbial necromass in croplands and bacterial necromass in forests: A global meta-analysis. Soil Biol. Biochem. 165, 108500. https://doi.org/10.1016/j.soilbio.2021.108500 \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":"Cultural practice, Legume, Soil bacteria, Soil fertility, Niger","lastPublishedDoi":"10.21203/rs.3.rs-6146869/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6146869/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe role of cowpea in improving soil fertility has been extensively studied at the rhizosphere level, yet its impact on bare soil properties remains unclear. Soil fertility management is crucial for sustainable agriculture, particularly in the context of climate change. This study evaluates the short-term effects of cowpea and mineral fertilization on soil microbiological and chemical properties. Two field trials were conducted in 2021 and 2022 during the rainy season. Soil samples were collected at three depths (0\u0026ndash;10 cm, 10\u0026ndash;20 cm, and 20\u0026ndash;30 cm) from plots where cowpea was grown either as a sole crop or with an additional application of 100 kg. ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of NPK. These samples were compared with those taken before sowing at the same depths. Results indicate minimal variation in soil characteristics across depths. However, bacterial abundance significantly decreased under sole cowpea cultivation and during the cropping season in 2022. A significant reduction in phosphorus levels was also observed in the sole cowpea plots (P\u0026thinsp;=\u0026thinsp;0.0001). These findings suggest that short-term cowpea monoculture may contribute to phosphorus depletion and reduced bacterial charge, potentially impacting long-term soil fertility. Further studies are needed to assess the long-term sustainability of cowpea-based cropping systems and to explore potential mitigation strategies.\u003c/p\u003e","manuscriptTitle":"Short-term influence of cowpea crop and mineral fertilization on the spatial and temporal distribution of soil microbiological and chemical properties","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-23 07:17:07","doi":"10.21203/rs.3.rs-6146869/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":"e35ae877-935a-48c8-9bc0-a159caf462fc","owner":[],"postedDate":"April 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-09T11:53:39+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-23 07:17:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6146869","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6146869","identity":"rs-6146869","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}