Influence of Enriched Cassava Peel Biochar on Growth, Yield and Proximate Composition of Sweet Potato

Influence of Enriched Cassava Peel Biochar on Growth, Yield and Proximate Composition of Sweet Potato | 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 Influence of Enriched Cassava Peel Biochar on Growth, Yield and Proximate Composition of Sweet Potato Otun Abiodun Abass, Ezekiel Akinkunmi Akinrinde, David Ojo, Ajibola-Akanbi Adediwura, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7223632/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 Sweet potato is one of the most important roots and tuber crop in terms of food security and its nutritional values. Over the years, the growth and yield of sweet potato is constrained by poor soil fertility and most farmers have adopted the use of inorganic fertilizers which has been known to acidify the soil. In recent years, farmers have increasingly adopted biochar as a targeted solution to mitigate this challenge, but due to its slow release of nutrients, it needs to enriched in order to increase the nutrients release to plant. Thus, this study is to evaluate the effect of enriched biochar on the growth, yield and proximate composition of sweet potato. This study was carried out at the NIHORT, Ibadan, Nigeria, where field experiment involved ten treatments; lime, NPK 15:15:15, compost and biochar sole, combined treatment combinations laid in a randomized complete block design with three replicates. There were a total of 30 plots with 6 m² per plot size and data were collected on growth and yield parameters. Treatments had no significant effect on the growth parameters. However, lime + biochar + compost gave higher tuber weight of 10 t/ha compared to other treatments applied. Also, the treatment combination; lime + biochar + compost increased the leaf nutrient concentrations of sweet potato. Further studies should be carried out to determine the residual effect of the enriched biochar on growth and yield of sweet potato. Biochar Lime organic fertilizer soil fertility Introduction Globally, Nigeria ranks as the second largest producer of sweet potatoes after China, and holds the highest producer within Africa, with annual output of 3.46 million metric tons. However, it is the only crop that has positive per capital annual rate of increase in production in sub-Saharan Africa (Tewe et al., 2003 ). The national production figures reported by FAO showed a rapid increase in production and area harvested in the 1990s, surpassing two million tonnes harvested from more than 300,000 hectares annually by the end of the decade (FAOSTAT, 2020). The important role of sweet potato is mainly in food security, it has shown a great potential as an income source for resource poor farmers (Rees et al., 2001 ). Various strategies have been recommended to address soil acidity, among which the use of lime (CaCO 3 ) remains the most widely adopted and effective in contemporary practice. Organic amendments and other soil management approaches also contribute to acidity mitigation (Ryan et al., 2018 ). The use of lime in agricultural soils has been shown to enhance microbial activity, influencing both bacterial and fungal population (Xuan et al., 2016 ). However, prolonged application may lead to certain drawbacks, such as re-acidification of the soil, increases compaction and the potential for leaching of essential mineral nutrients (Wang, Jiang 2017 ). In recent times, the use of organic amendments such as biochar, an example of pyrogenic carbon has gained wide attention for enhancing crop yield across various soil types, including acidic conditions. Due to its resistance to microbial breakdown, biochar is recognized as a sustainable and environmentally friendly amendment, capable of performing its beneficial roles over extended periods (Adeyika et al ., 2020). Biochar has been shown to enhance the availability of the key soil nutrients such as potassium (K), calcium (Ca), magnesium (Mg), and phosphorus (P), while also improving soil physical properties including aeration, moisture retention, and bulk density. Its application has also been linked to increased microbial population within the soil (Syuhada et al., 2016 ; Ullah et al. , 2018). Furthermore, integrating biochar into soil either independently or in combination with inorganic fertilizers has been reported to provide adequate macro- and micronutrient required for plant growth (Piashs et al. , 2021). In addition, biochar contributes to the build-up of soil organic carbon and serves as a carbon sink due to its slow mineralization (Joseph et al., 2020 ). However, studies also indicate that biochar may influence soil Co 2 emissions, with outcomes varying depending on the type of biochar used and its persistence in the soil The main challenges of sweet potato production are non-application of fertilizer by farmers. In the past, farmers cultivated sweet potato without the use of fertilizers and still obtained satisfactory yields. However, due to land fragmentation, continuous cultivation of sweet potato on the same plots has become common, leading to soil nutrients depletion and a subsequent decline in yield performance. As a result, fertilizer application is necessary to replenish the nutrients lost through intensive cropping. Furthermore, the use of enriched form of biochar is necessary so as to increase the amount and rate of nutrients release to plant. Therefore, investigation was centered on the growth, yield and nutritional values of sweet potato under biochar, lime, NPK 15:15:15, compost sole and treatments combinations. Materials and Methods Experimental location The experiment was carried out at the field plot of National Horticultural Research Institute (NIHORT), Idi-Ishin Jericho GRA Ibadan, Oyo State in the Southern Guinea Savannah ecological zone of Nigeria. The farm is situated at Longitude (3° 50' E) and Latitude (3° 23' N) and altitude of approximately 144m above sea level. The site also has a uniform slope 7%. The soil of the study site belongs to Alfisol, classified as Typic Kanhaplustalf according to USDA classification and locally classified as Iwo series (Smyth and Montgomery 1962). Experimental Materials Sweet potato variety (Ex-Igbariam) was obtained from National Root Crops Research Institute (NRCRI), Nigeria. The feedstock used for the biochar production was dried cassava peel and biochar which was produced at the screen house of Crop and Horticultural Sciences Department, University of Ibadan, Nigeria. The Compost used for the study was made from poultry waste and mango leaves obtained from National Horticultural Research Institute (NIHORT), Ibadan, Oyo State. NPK 15:15:15 and Lime (CaCO₃) were obtained from a reputable agro-input supplier in Bodija, Ibadan, Oyo State, ensuring consistency in nutrient composition. Experimental Design The experiment comprised of ten (10) treatments laid out on the field in a randomized complete block design (RCBD) with three replicates. There were a total of 30 plots, each of 2 m by 3 m (6m²) with 1 m spacing between plots and blocks which gives a total experimental land area of 319m². Planting of sweet potato vines was done using 12cm long vines and ensuring that at least 2 nodes were dipped into the soil. The spacing was 75cm by 50cm which gives total of 16 stands per plot while the total plant density was 480 plant stands in total. The compost and biochar were worked into the soil two weeks before planting. Experimental Procedures Planting of sweet potato vines was done using 12 cm long vines and ensuring that at least 2 nodes were dipped into the soil. The spacing was 75 cm by 50 cm which gives total of 16 stands per plot while the plant density was 750 plant stands in total. The compost and biochar were worked into the soil two weeks before planting. Planting was done September, 2023 while harvesting was carried out December, 2023. Treatments and Fertilizer Rates Control (Zero fertilizer application), Biochar (333.33 kg/ha), Compost (3000 kg/ha), Lime (CaCO₃) (112.5 kg/ha), NPK 15:15:15 (400 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + Compost (1,500 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + NPK 15:15:15 (200 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + Biochar 166.67 kg/ha), Lime CaCO₃) (37.5 kg/ha) + Compost (1000 kg/ha) + Biochar (111.11 kg/ha) and Lime CaCO₃) 28.13 kg/ha) + Compost 750 kg/ha) + Biochar (83.33 kg/ha) + NPK 15:15:15 (100 kg/ha). Data Collection The following growth and yield data were collected on sweet potato at 4, 8 and 12 weeks after planting (WAP): Growth parameters which include: Vine length (cm): The vine length was measured using a flexible tape from the base to the tip of the main shoot at 4 weeks intervals. Vine girth (mm): Vernier caliper was used to measure the stem diameter. Number of leaves: The number of leaves was obtained by counting at 4 weeks intervals. Number of branches: The number of branches was obtained by counting the branches of selected plant stands. Yield parameters which include: Number of storage roots: The number of tubers per plant was counted. Weight of storage roots: This was done by weighing each plot yield using weighing scale. Pyrolysis of Biochar The biochar used in this study was produced using a locally fabricated pyrolysis unit consisting of three main compartments: an insulated outer metal box with a cover, an inner cylindrical chamber with its own lid and a lower outlet for collecting the charred material. Dried cassava peel feedstock was loaded into the inner chamber and securely sealed. Pre-heated charcoal was then introduced into the space surrounding the inner cylinder to initiate the pyrolysis process, after which the entire reactor was covered. A timer was set to monitor the duration of the charring process, which lasted approximately five hours. Upon completion, the residual material inside the inner chamber, which was fully charred was identified as biochar. This biochar was discharged through the lower outlet and water was immediately sprinkled over the hot char to prevent further combustion. The resulting biochar was then air-dried for one week before being applied in the experimental treatments. Proximate Analysis Procedures Proximate Analysis Procedures: Chemical analyses of sweet potato tuber samples were conducted in duplicate using standard protocols outlined by the Association of Official Analytical Chemists (AOAC, 18th Edition, 2005). The parameters assessed included crude protein, crude fat, moisture content, dry matter, ash, and crude fiber. Crude Protein: This was determined using the semi-micro Kjeldahl method, which involves three sequential steps: digestion, distillation, and titration. This technique quantifies nitrogen content, which is then converted to protein percentage using a standard conversion factor. Crude Fat: It was analyzed using the Soxhlet extraction method. One gram of dried sweet potato leaf sample was placed into a fat-free extraction thimble and lightly packed with cotton wool. The thimble was inserted into the extractor, which was connected to a reflux condenser and a pre-weighed 250 ml Soxhlet flask. The flask was filled to three-quarters capacity with petroleum ether (boiling point: 40–60°C) and heated for six hours with continuous water flow to condense ether vapors. After extraction, the flask containing the extracted fat was dried to a constant weight in an oven. Crude fat content was calculated using the formula: Moisture Content and Dry Matter: They were determined by oven-drying two grams of fresh tuber sample in a pre-weighed crucible at 100°C for 24 hours. After drying, the crucible was cooled in a desiccator and reweighed. Dry matter percentage was calculated as: where (W o ) is the weight of the empty crucible, (W 1 ) is the weight of crucible plus fresh sample, and (W 1 ) is the weight after drying. Ash Content: This was determined by incinerating two grams of tuber sample in a porcelain crucible at 550°C for four hours in a muffle furnace. The resulting white ash was cooled first in air, then in a desiccator, and weighed. Ash percentage was calculated as: Crude Fiber: It was analyzed by refluxing two grams of tuber sample with 100 ml of 0.255N sulfuric acid for one hour. The mixture was filtered through a fiber sieve cloth, and the residue was then refluxed with 100 ml of 0.313N sodium hydroxide for another hour. After filtration, 10 ml of acetone was added to dissolve organic residues, followed by washing with hot water. The residue was transferred to a crucible, dried in an oven, cooled in a desiccator, and weighed (W₁). The crucible was then ashed at 550°C for four hours, cooled, and reweighed (W₂). Crude fiber was calculated as: Nutrient Use Efficiency Sweet potato leaf samples were collected, oven dried and weighed. The dried samples were further processed into powder form by milling after which they were analyzed for their nutrient contents. Nitrogen use efficiency was determined using the formula (NUE = Yield) (Rahimizadeh et al ., 2010) N – supply (kg) Phosphorus use efficiency was determined using the formula (PUE = Yield) P – supply (kg) Potassium use efficiency was determined using the formula (KUE = Yield) K – supply (kg) Statistical Analysis Data collected were subjected to Analysis of Variance (ANOVA) using General Statistical Package (GENSTAT) 4th edition, 2015 while significant means were separated using Duncan multiple range test (DMRT) at P < 0.05. Results and Discussion The baseline properties of the experimental soil are presented in Table 1 below. The soil analysis revealed that the experimental soil possessed a loamy sand texture, characterized by high sand content and relatively low proportions of silt and clay, indicative of moderate water retention and aeration potential. The soil pH was slightly acidic, falling marginally below the optimum range for most arable crops, as proposed by Chude et al . (2012), suggesting moderate availability of essential nutrients. Organic carbon and total nitrogen were both below critical thresholds, indicating poor soil fertility and reduced potential for microbial activity. However, available phosphorus was substantially above the critical range, suggesting potential for early root development and shoot growth. Among the exchangeable bases, potassium was critically low, while calcium and magnesium levels were considered adequate, contributing to soil structural stability and enzymatic functions. Exchangeable acidity remained minimal. Furthermore, micronutrient analysis revealed elevated concentrations of iron and manganese, well above critical levels, potentially enhancing chlorophyll synthesis and enzymatic activity. However, levels of zinc and copper were below optimal thresholds, which could affect reproductive development and photosynthetic efficiency if not supplemented. Table 1: Soil Physicochemical Properties of the Experimental Site The values on table 2 represent Pearson correlation coefficients (r), indicating the strength and direction of linear relationships among parameters. The correlation analysis reveals strong and positive associations among nutrient level, vegetative growth traits and tuber yield in sweet potato. However, the correlation between nutrient level and yield was the strongest, indicating that increasing nutrient availability substantially enhanced storage root production. This aligns with findings by Agele et al. (2017), who reported that nutrient enrichment particularly in nutrient-depleted soils boosts tuber initiation and bulking through improved assimilate partitioning. The number of leaves also correlated strongly with nutrient level and yield, suggesting that leaf development played a vital role in canopy establishment and photosynthetic capacity, influencing biomass accumulation and yield. Furthermore, plant height exhibited a moderately strong relationship with both nutrient level and yield, showing its significance as a growth indicator. It typically reflects improved vegetative vigor under favorable nutrient conditions, as suggested by Mukhopadhyay et al . (2011). Table 2: Pearson correlation coefficient relating nutrient application, growth and yield parameters Number of leaves Nutrient level Plant height Yield Number of leaves 1 Nutrient level 0.9035 1 Plant height 0.7501 0.6667 1 Yield 0.9129 0.9471 0.8246 1 It was observed on table 3 that there were no significant (p= 0.05) differences in sweet potato growth responses under various treatments applications. However, treatments combining lime + NPK 15:15:15 promoted more vigorous vine growth. Vine length recorded under the lime + NPK 15:15:15 treatment suggests improved nutrient synergy and soil pH adjustment, which have enhanced nutrient uptake efficiency. According to Agele et al . (2017), liming acidic soils can improve root development and optimize fertilizer response in tuber crops. Furthermore, the enhanced vine diameter under lime + compost + biochar treatment application suggests structural and biochemical improvements. This aligns with findings by Sika and Hardie (2014), who reported that biochar improves soil physical properties and root proliferation when co-applied with organic matter. Table 3: Effect of treatments application on growth parameters of sweet potato Treatments No. of branches No. of leaves Vine diameter (cm) Vine length (cm) Control 3.67 72.93 0.46 103.10 Biochar 2.95 83.39 0.45 92.50 Compost 2.59 62.73 0.52 96.40 Lime 2.10 99.87 0.59 92.20 NPK 15:15:15 2.40 51.17 0.61 67.80 Lime + Biochar 3.33 80.67 0.67 107.90 Lime + Compost 2.40 60.00 0.49 98.00 Lime + NPK 15:15:15 2.67 71.64 0.63 188.80 Lime + Compost + Biochar 2.57 91.37 0.73 107.10 Lime + Compost + Biochar + NPK 3.13 82.39 0.45 92.50 SED NS NS NS NS NS: not significant, No.: Number, cm: centimeter As presented on table 4, the response of sweet potato to various soil fertility treatments revealed that integrated inputs had more positive significant on storage root development compared to individual amendments. The combined treatment application of lime + compost + biochar produced the highest storage root yield (10.00 t/ha) compared to all other treatments applied. This attributed to improved soil pH, enhanced microbial activity and better moisture and nutrient retention reported by Sika and Hardie (2014). Also, the treatment application of lime + biochar yielded the highest number of storage roots per hectare, highlighting the potential of biochar to boost tuber formation when combined with soil lime. Lehmann and Joseph (2015) noted that biochar amendments can enhance root proliferation and reduce nutrient leaching, particularly in sandy and acidic soils. Table 4: Effect of treatment applications on yield of sweet potato Treatments Storage root weight (t/ha) No. of storage root/ha Control 5.33 d 33,333 c Biochar 5.39 d 38,300 bc Compost 6.61 c 46,667 ab Lime 7.72 b 35,000 c NPK 15:15:15 5.83 cd 46,667 ab Lime + Biochar 8.56 b 51,667 a Lime + Compost 5.89 b 40,000 bc Lime + NPK 15:15:15 5.83 cd 46,667 ab Lime + Compost + Biochar 10 a 38,333 bc Lime + Compost + Biochar + NPK 6.28 cd 40,000 bc SED 0.4296 2.188 Means followed by the same letter in a column are not significantly different by DMRT at (P<0.005) Table 5 below shows that the protein content of sweet potato studied ranged from 3.90 to 4.57% on dry weight. These values are in the same range of 3.28 to 4.16% obtained by (Ukom et al ., 2009) except for treatment lime + compost + biochar + NPK 15:15:15 and biochar. The ash content varied from 1.07 to 1.80% which is closely around the range of values 0.40 to 2.35% reported by (Eleazu and Eleazu, 2012; Eleazu and Ironua, 2013; Ellong et al., 2014). However, sole application of lime had the lowest fat content while control had the highest fat content. There was significant difference in fat content among the treatment applied. The fat contents were lower than the values reported by (Ishida et al., 2000). Fat is involved in the insulation of the body organs and in the maintenance of the body temperature and cell function. Crude fiber content as presented in the table varied from 1.24 to 1.49% in dry weight basis. The dry matter content was observed that it ranges from 90.80 to 92.50%. This also shows that all the ten treatments had similar dry matter content values. This result supports the findings of Ellong et al. (2014). The moisture content values were between 7.50 to 9.20% which were within the range values reported by (Ukom et al ., 2009). For carbohydrate, lime + compost had the highest carbohydrate content while sole application of biochar had the lowest carbohydrate content. These results are in support of the findings of (Ukom et al., 2009). Table 5: Proximate composition of sweet potato under the influence of treatments application Treatments CP % Ash % Fat % CF % D M% MC % CHO % Control 4.26b 1.80c 0.34 1.49a 91.85 8.15d 84.69d Biochar 4.57a 1.07a 0.30 1.26e 91.61 8.39c 83.68i Compost 4.08cd 1.17bc 0.31 1.24e 91.60 8.40c 84.77c Lime 3.98de 1.40b 0.26 1.46ab 91.75 8.25cd 84.85h NPK 15:15:15 4.03cde 1.20bc 0.29 1.29de 90.80 9.20a 83.99g Lime + Biochar 4.05cd 1.10c 0.33 1.35cde 90.80 9.20a 83.97g Lime + Compost 3.90e 1.16bc 0.28 1.30de 92.50 7.50e 85.86a Lime + NPK 15:15:15 4.15bc 1.14c 0.29 1.43bc 91.66 8.34cd 84.58a Lime + Compost + Biochar 4.10cd 1.17bc 0.30 1.40bce 90.82 9.18a 83.85e Lime + Compost + Biochar + NPK 4.22b 1.14c 0.28 1.34cde 91.25 8.75b 84.27f SED 0.1403 0.2218 NS 0.1126 0.223 0.2188 0.01377 Means followed by the same letter in a column are not significantly different by DMRT at (P<0.005) CP = Crude protein, CF = Crude fiber, MC = Moisture content, CHO = Carbohydrate, DM = Dry matter, NS = Not significant As presented on table 6, the Nitrogen use efficiency (NUE), Phosphorus use efficiency (PUE) and Potassium use efficiency (KUE). Increase in leaf nutrient concentrations of sweet potato can be related to soil quality improvement, nutrient release into the soil solution, increase in soil chemical properties and balanced nutrition of plants. According to (Farrar et al ., 2019), biochar-based fertilizer application has been observed to increase growth and uptake of N, P and K and also, compost application has been found to increase the uptake of N, P and K. Furthermore, acidic soils with Al saturation seriously limit sweet potato yield (Ila’ava et al ., 2000), therefore, application of lime alongside enriched biochar has positively increase the NUE, PUE and KUE of sweet potato leaves amongst other treatments. Table 6: Effect of treatments on the Nutrient Use Efficiency of sweet potato leaves Treatments NUE PUE KUE Control 2.07fg 41.98 6.11bc Biochar 3.21d 43.82 5.83c Compost 2.17f 35.73 5.29c Lime 3.8d 87.73 16.25a NPK 15:15:15 2.72e 35.06 4.74c Lime + Biochar 4.89ab 83.11 10.7b Lime + Compost 1.91g 37.04 6.73bc Lime + NPK 15:15:15 3.2d 35.51 5.18c Lime + Compost + Biochar 6.21a 96.15 19.05a Lime + Compost + Biochar + NPK 4.49c 57.61 5.71c SED 0.0765 0.01917 1.580 Means followed by the same letter in a column are not significantly different by DMRT at (P<0.005) NUE: Nutrient Use Efficiency, PUE: Phosphorus Use Efficiency, KUE: Potassium Use Efficiency. As shown on table 7 below, the effect of profitability index of sweet potato production using ten treatment applications which was carried out in order to assess the cost and profit implication of each treatment applied. The total cost for each treatment on table 7 was done by adding up all expenses in Nigeria naira (₦) from land acquisition to harvesting of tubers and also transporting of harvested tubers to the farm gate was calculated. Here, treatment three (NPK 15:15:15) had the highest total expenditure whereas, it didn’t give the highest profitability index. Gross profit was calculated by multiplying 1 kg (which was ₦200.00 as at when this research work was carried out) value price of sweet potato by tuber weight. However, the profitability index is thus, calculated as the gross profit divided by the total cost which connotes that for every ₦1 spent, there is a corresponding monetary value in ₦ gained as profit. Treatment combination of lime + Compost + biochar gave the highest profitability index of 3.51. I.e., ₦1 spent on treatment combination of lime + compost + biochar gave a profit of ₦3.51 in return, while NPK 15:15:15 gave the lowest profitability index. Table 7: Effect of profitability index of sweet potato Treatments Yield (t/ha) Total cost (₦) Gross profit (₦) Control 5.5 434,166 760,000 1.7 Biochar 5.39 550,816 1,078,000 1.96 Compost 6.16 626,166 1,232,000 1.97 Lime 7.72 538,406 1,544,000 1.94 NPK 15:15:15 5.33 654,166 1,266,000 1.63 Lime + Biochar 8.56 543,611 1,711,200 3.15 Lime + Compost 5.89 580,286 1,178,000 2.02 Lime + NPK 15:15:15 5.83 595,286 1,166,000 1.96 Lime + Compost + Biochar 10 570,463 2,000,000 3.51 Lime + Compost + Biochar + NPK 6.28 591,389 1,256,000 2.12 P.I.: Profitability Index Conclusion From the results obtained in this research, it is evident that the applied treatments did not have significant influence on the growth of sweet potato in the study area, also, enriched biochar did not influence proximate compositions of sweet potato storage roots while liming enriched biochar gave better yield of sweet potato than other treatments applied. It is, therefore, concluded that organic fertilizer should be used to increase sweet potato storage roots quantity and quality. However, further studies need to be carried out to ascertain the residue impact of biochar on sweet potato production. Declarations Author contributions : O.A.A. Conceived and designed the project. E.AA. and D.O. supervised the research work and provided guidance throughout the study. A.A.A. and R.M.A. were responsible for materials preparation and methodology implementation. A.G.G. and O.S.Y. carried out the laboratory analysis. O.A.A. wrote the introduction and Results sections. E.A.A. and D.O. critically reviewed and edited the manuscript. All authors read and approved the final version of the manuscript. Ethical Statement: This study did not involve human participants, animal subjects, or endangered plant species. The sweet potato vine used in the experiment was obtained from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria. The plant material was cultivated and legally sourced; no wild collection was involved, and therefore no special permits, licenses, or ethical approvals were required for its use in this research. Data Availability Statement: All data generated or analyzed during this study are included in this published article Funding: No funding was received for conducting this study. Ethics, Consent to Participate, and Consent to Publish: The plant used in this study was Ex-Igbariam, a cultivated type pirchased from the National Root Crops Research Institute (NRCRI), Nigeria. Vine cuttings were selected as the planting material in line with local or national guidelines. Permissions to collect the plants/plant parts: No special permissions or licenses were required for the collection of plant material used in this study. The vines were purchased from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria, a recognized and authorized institution for the distribution of certified planting materials. The use of cultivated vines obtained through legal purchase does not require additional collection permits, as the material was not sourced from the wild or protected areas. Competing interests The authors declare no competing interests. References Adekiya, A.O.; Agbede, T.M.; Olayanju, A.; Ejue, W.S.; Adekanye, T.A.; Adenusi, T.T.; Ayeni, 2020. amendment: Impact on chemical properties and corn nutrient uptake in a Podzol. Can. J. and wood-based biochars. Geoderma 2021, 397, 115100. Agele, S. O., Ajayi, A. E., & Iremiren, G. O. (2017). Growth and yield response of sweet potato (Ipomoea batatas L.) to different soil fertility management practices in a rainforest zone of Nigeria. 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A Biochar as soil amendment: Impact on chemical properties and corn nutrient uptake in a Podzol. Can. J. Soil Sci., 96, 400–412. Tewe, F.E. Ojeniyi, O.A. Abu (2003). Sweet potato Production, Utilization and Marketing in Nigeria. Social Science Department International Potato Center (CIP), Lima, Peru. Pg.19-36 tubersum L.) and green mass of fodder sunflower (Helianthus annuus L.). Ukom, A. N., Ojimelukwe, P. C., & Okpara, D. A. (2009). Nutrient composition of selected sweet potato (Ipomoea batatas L. Lam) varieties as influenced by different levels of nitrogen fertilizer application. Pakistan Journal of Nutrition, 8(11), 1791–1795. https://doi.org/10.3923/pjn.2009.1791.1795 Ukom, A., Ojimelukwe, P. C., and Okpara, D. (2009). Nutritional composition of selected sweet potato. Pakistan journal of Nutrition, 8 (11), 1791 – 1795. Ullah, Z.; Akmal, M.; Ahmed, M.; Ali, M.; Jamali, A.Z. (2021) Effect of biochar on soil chemical properties and nutrient availability in sandstone and shale derived soils. J.Biol. Environ. Sci. 2018, 12, 96–103. Available online: http://www.innspub.net Wang, M.; Jiang, X.-J. (2017). Effects of applying lime and calcium montmorillonite on nitrification dynamics in acidic soil. J. Agric. Resour. Environ. 34, 47–53. Xuan, W.; Xiong, W.; Huang, T.; Ran, W.; Li, D.; Shen, Q.; Li, Q.; Zhang, R.2016 (2016). Swine manure and quick lime have different impacts on chemical properties and composition of bacterial communities of an acidic soil. Appl. Soil Ecol. 100, 38–44. 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. 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08:24:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":833431,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7223632/v1/f213e199-51af-42ab-bdb5-82f826400ce9.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eInfluence of Enriched Cassava Peel Biochar on Growth, Yield and Proximate Composition of Sweet Potato\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGlobally, Nigeria ranks as the second largest producer of sweet potatoes after China, and holds the highest producer within Africa, with annual output of 3.46\u0026nbsp;million metric tons. However, it is the only crop that has positive per capital annual rate of increase in production in sub-Saharan Africa (Tewe et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). The national production figures reported by FAO showed a rapid increase in production and area harvested in the 1990s, surpassing two million tonnes harvested from more than 300,000 hectares annually by the end of the decade (FAOSTAT, 2020). The important role of sweet potato is mainly in food security, it has shown a great potential as an income source for resource poor farmers (Rees et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Various strategies have been recommended to address soil acidity, among which the use of lime (CaCO\u003csub\u003e3\u003c/sub\u003e) remains the most widely adopted and effective in contemporary practice. Organic amendments and other soil management approaches also contribute to acidity mitigation (Ryan et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The use of lime in agricultural soils has been shown to enhance microbial activity, influencing both bacterial and fungal population (Xuan et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). However, prolonged application may lead to certain drawbacks, such as re-acidification of the soil, increases compaction and the potential for leaching of essential mineral nutrients (Wang, Jiang \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In recent times, the use of organic amendments such as biochar, an example of pyrogenic carbon has gained wide attention for enhancing crop yield across various soil types, including acidic conditions. Due to its resistance to microbial breakdown, biochar is recognized as a sustainable and environmentally friendly amendment, capable of performing its beneficial roles over extended periods (Adeyika \u003cem\u003eet al\u003c/em\u003e., 2020). Biochar has been shown to enhance the availability of the key soil nutrients such as potassium (K), calcium (Ca), magnesium (Mg), and phosphorus (P), while also improving soil physical properties including aeration, moisture retention, and bulk density. Its application has also been linked to increased microbial population within the soil (Syuhada et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Ullah \u003cem\u003eet al.\u003c/em\u003e, 2018). Furthermore, integrating biochar into soil either independently or in combination with inorganic fertilizers has been reported to provide adequate macro- and micronutrient required for plant growth (Piashs \u003cem\u003eet al.\u003c/em\u003e, 2021). In addition, biochar contributes to the build-up of soil organic carbon and serves as a carbon sink due to its slow mineralization (Joseph et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, studies also indicate that biochar may influence soil Co\u003csub\u003e2\u003c/sub\u003e emissions, with outcomes varying depending on the type of biochar used and its persistence in the soil\u003c/p\u003e\u003cp\u003eThe main challenges of sweet potato production are non-application of fertilizer by farmers. In the past, farmers cultivated sweet potato without the use of fertilizers and still obtained satisfactory yields. However, due to land fragmentation, continuous cultivation of sweet potato on the same plots has become common, leading to soil nutrients depletion and a subsequent decline in yield performance. As a result, fertilizer application is necessary to replenish the nutrients lost through intensive cropping. Furthermore, the use of enriched form of biochar is necessary so as to increase the amount and rate of nutrients release to plant. Therefore, investigation was centered on the growth, yield and nutritional values of sweet potato under biochar, lime, NPK 15:15:15, compost sole and treatments combinations.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eExperimental location\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe experiment was carried out at the field plot of National\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eHorticultural Research Institute (NIHORT), Idi-Ishin Jericho GRA Ibadan, Oyo State in the Southern Guinea Savannah ecological zone of Nigeria. The farm is situated at Longitude (3\u0026deg; 50\u0026apos; E) and Latitude (3\u0026deg; 23\u0026apos; N) and altitude of approximately 144m above sea level. The site also has a uniform slope 7%. The soil of the study site belongs to Alfisol, classified as Typic Kanhaplustalf according to USDA classification and locally classified as Iwo series (Smyth and Montgomery 1962).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSweet potato variety (Ex-Igbariam) was obtained from National Root Crops Research Institute (NRCRI), Nigeria. The feedstock used for the biochar production was dried cassava peel and biochar which was produced at the screen house of Crop and Horticultural Sciences Department, University of Ibadan, Nigeria. The Compost used for the study was made from poultry waste and mango leaves obtained from National Horticultural Research Institute (NIHORT), Ibadan, Oyo State. NPK 15:15:15 and Lime (CaCO₃) were obtained from a reputable agro-input supplier in Bodija, Ibadan, Oyo State, ensuring consistency in nutrient composition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental Design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experiment comprised of ten (10) treatments laid out on the field in a randomized complete block design (RCBD) with three replicates. There were a total of 30 plots, each of 2 m by 3 m (6m\u0026sup2;) with 1 m spacing between plots and blocks which gives a total experimental land area of 319m\u0026sup2;. Planting of sweet potato vines was done using 12cm long vines and ensuring that at least 2 nodes were dipped into the soil. The spacing was 75cm by 50cm which gives total of 16 stands per plot while the total plant density was 480 plant stands in total. The compost and biochar were worked into the soil two weeks before planting.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental Procedures\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePlanting of sweet potato vines was done using 12 cm long vines and ensuring that at least 2 nodes\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ewere dipped into the soil. The spacing was 75 cm by 50 cm which gives total of 16 stands per plot\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ewhile the plant density was 750 plant stands in total. The compost and biochar were worked\u0026nbsp;\u003c/p\u003e\n\u003cp\u003einto the soil two weeks before planting. Planting was done September, 2023 while harvesting\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ewas carried out December, 2023.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTreatments and Fertilizer Rates \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eControl (Zero fertilizer application), Biochar (333.33 kg/ha), Compost (3000 kg/ha), Lime (CaCO₃) (112.5 kg/ha), NPK 15:15:15 (400 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + Compost (1,500 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + NPK 15:15:15 (200 kg/ha), Lime (CaCO₃) (56.25 kg/ha) + Biochar 166.67 kg/ha), Lime CaCO₃) (37.5 kg/ha) + Compost (1000 kg/ha) + Biochar (111.11 kg/ha) and Lime CaCO₃) 28.13 kg/ha) + Compost 750 kg/ha) + Biochar (83.33 kg/ha) + NPK 15:15:15 (100 kg/ha).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe following growth and yield data were collected on sweet potato at 4, 8 and 12 weeks after\u003c/p\u003e\n\u003cp\u003eplanting (WAP):\u003c/p\u003e\n\u003cp\u003eGrowth parameters which include:\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eVine length (cm): The vine length was measured using a flexible tape from the base to the tip of the main shoot at 4 weeks intervals.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eVine girth (mm): Vernier caliper was used to measure the stem diameter.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Number of leaves: The number of leaves was obtained by counting at 4 weeks intervals.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eNumber of branches: The number of branches was obtained by counting the branches of selected plant stands.\u0026nbsp;\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eYield parameters which include:\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eNumber of storage roots: The number of tubers per plant was counted.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eWeight of storage roots: This was done by weighing each plot yield using weighing scale.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePyrolysis of Biochar\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe biochar used in this study was produced using a locally fabricated pyrolysis unit consisting of three main compartments: an insulated outer metal box with a cover, an inner cylindrical chamber with its own lid and a lower outlet for collecting the charred material. Dried cassava peel feedstock was loaded into the inner chamber and securely sealed. Pre-heated charcoal was then introduced into the space surrounding the inner cylinder to initiate the pyrolysis process, after which the entire reactor was covered. A timer was set to monitor the duration of the charring process, which lasted approximately five hours. Upon completion, the residual material inside the inner chamber, which was fully charred was identified as biochar. This biochar was discharged through the lower outlet and water was immediately sprinkled over the hot char to prevent further combustion. The resulting biochar was then air-dried for one week before being applied in the experimental treatments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eProximate Analysis Procedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eProximate Analysis Procedures:\u003c/p\u003e\n\u003cp\u003eChemical analyses of sweet potato tuber samples were conducted in duplicate using standard protocols outlined by the Association of Official Analytical Chemists (AOAC, 18th Edition, 2005). The parameters assessed included crude protein, crude fat, moisture content, dry matter, ash, and crude fiber.\u003c/p\u003e\n\u003cp\u003eCrude Protein: This was determined using the semi-micro Kjeldahl method, which involves three sequential steps: digestion, distillation, and titration. This technique quantifies nitrogen content, which is then converted to protein percentage using a standard conversion factor.\u003c/p\u003e\n\u003cp\u003eCrude Fat: It was analyzed using the Soxhlet extraction method. One gram of dried sweet potato leaf sample was placed into a fat-free extraction thimble and lightly packed with cotton wool. The thimble was inserted into the extractor, which was connected to a reflux condenser and a pre-weighed 250 ml Soxhlet flask. The flask was filled to three-quarters capacity with petroleum ether (boiling point: 40\u0026ndash;60\u0026deg;C) and heated for six hours with continuous water flow to condense ether vapors. After extraction, the flask containing the extracted fat was dried to a constant weight in an oven. Crude fat content was calculated using the formula: \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1759320339.png\" width=\"340\" height=\"111\"\u003e\u003c/p\u003e\n\u003cp\u003eMoisture Content and Dry Matter: They were determined by oven-drying two grams of fresh tuber sample in a pre-weighed crucible at 100\u0026deg;C for 24 hours. After drying, the crucible was cooled in a desiccator and reweighed. Dry matter percentage was calculated as: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1759320364.png\" width=\"616\" height=\"178\"\u003e\u003c/p\u003e\n\u003cp\u003ewhere (W\u003cu\u003eo\u003c/u\u003e) is the weight of the empty crucible, (W\u003csub\u003e1\u003c/sub\u003e) is the weight of crucible plus fresh sample, and (W\u003csub\u003e1\u003c/sub\u003e) is the weight after drying.\u003c/p\u003e\n\u003cp\u003eAsh Content: This was determined by incinerating two grams of tuber sample in a porcelain crucible at 550\u0026deg;C for four hours in a muffle furnace. The resulting white ash was cooled first in air, then in a desiccator, and weighed. Ash percentage was calculated as: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1759320390.png\" width=\"478\" height=\"114\"\u003e\u003c/p\u003e\n\u003cp\u003eCrude Fiber: It was analyzed by refluxing two grams of tuber sample with 100 ml of 0.255N sulfuric acid for one hour. The mixture was filtered through a fiber sieve cloth, and the residue was then refluxed with 100 ml of 0.313N sodium hydroxide for another hour. After filtration, 10 ml of acetone was added to dissolve organic residues, followed by washing with hot water. The residue was transferred to a crucible, dried in an oven, cooled in a desiccator, and weighed (W₁). The crucible was then ashed at 550\u0026deg;C for four hours, cooled, and reweighed (W₂). Crude fiber was calculated as: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1759320420.png\" width=\"405\" height=\"141\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNutrient Use Efficiency\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSweet potato leaf samples were collected, oven dried and weighed. The dried samples were further processed into powder form by milling after which they were analyzed for their nutrient contents.\u003c/p\u003e\n\u003cp\u003eNitrogen use efficiency was determined using the formula (NUE = Yield) (Rahimizadeh \u003cem\u003eet al\u003c/em\u003e., 2010)\u003c/p\u003e\n\u003cp\u003eN \u0026ndash; supply (kg)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePhosphorus use efficiency was determined using the formula (PUE = Yield)\u003c/p\u003e\n\u003cp\u003eP \u0026ndash; supply (kg)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePotassium use efficiency was determined using the formula (KUE = Yield)\u003c/p\u003e\n\u003cp\u003eK \u0026ndash; supply (kg)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData collected were subjected to Analysis of Variance (ANOVA) using General Statistical Package (GENSTAT) 4th edition, 2015 while significant means were separated using Duncan multiple range test (DMRT) at P \u0026lt; 0.05. \u0026nbsp;\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eThe baseline properties of the experimental soil are presented in Table 1 below. The soil analysis revealed that the experimental soil possessed a loamy sand texture, characterized by high sand content and relatively low proportions of silt and clay, indicative of moderate water retention and aeration potential. The soil pH was slightly acidic, falling marginally below the optimum range for most arable crops, as proposed by Chude \u003cem\u003eet al\u003c/em\u003e. (2012), suggesting moderate availability of essential nutrients. Organic carbon and total nitrogen were both below critical thresholds, indicating poor soil fertility and reduced potential for microbial activity. However, available phosphorus was substantially above the critical range, suggesting potential for early root development and shoot growth. Among the exchangeable bases, potassium was critically low, while calcium and magnesium levels were considered adequate, contributing to soil structural stability and enzymatic functions. Exchangeable acidity remained minimal. Furthermore, micronutrient analysis revealed elevated concentrations of iron and manganese, well above critical levels, potentially enhancing chlorophyll synthesis and enzymatic activity. However, levels of zinc and copper were below optimal thresholds, which could affect reproductive development and photosynthetic efficiency if not supplemented.\u003c/p\u003e\n\u003cp\u003eTable 1: Soil Physicochemical Properties of the Experimental Site\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1759320597.png\" width=\"766\" height=\"554\"\u003e\u003c/p\u003e\n\u003cp\u003eThe values on table 2 represent Pearson correlation coefficients (r), indicating the strength and direction of linear relationships among parameters. The correlation analysis reveals strong and positive associations among nutrient level, vegetative growth traits and tuber yield in sweet potato. However, the correlation between nutrient level and yield was the strongest, indicating that increasing nutrient availability substantially enhanced storage root production. This aligns with findings by Agele \u003cem\u003eet al.\u003c/em\u003e (2017), who reported that nutrient enrichment particularly in nutrient-depleted soils boosts tuber initiation and bulking through improved assimilate partitioning. The number of leaves also correlated strongly with nutrient level and yield, suggesting that leaf development played a vital role in canopy establishment and photosynthetic capacity, influencing biomass accumulation and yield. \u0026nbsp;Furthermore, plant height exhibited a moderately strong relationship with both nutrient level and yield, showing its significance as a growth indicator. It typically reflects improved vegetative vigor under favorable nutrient conditions, as suggested by Mukhopadhyay \u003cem\u003eet al\u003c/em\u003e. (2011).\u003c/p\u003e\n\u003cp\u003eTable 2: Pearson correlation coefficient relating nutrient application, growth and yield parameters\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003eNumber of leaves\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003eNutrient level\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003ePlant height\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eYield\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003eNumber of leaves\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003eNutrient level\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e0.9035\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003ePlant height\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e0.7501\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e0.6667\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003eYield\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e0.9129\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e0.9471\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e0.8246\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIt was observed on table 3 that there were no significant (p= 0.05) differences in sweet potato growth responses under various treatments applications. However, treatments combining lime + NPK \u0026nbsp;15:15:15 promoted more vigorous vine growth. Vine length recorded under the lime + NPK 15:15:15 treatment suggests improved nutrient synergy and soil pH adjustment, which have enhanced nutrient uptake efficiency. According to Agele \u003cem\u003eet al\u003c/em\u003e. (2017), liming acidic soils can improve root development and optimize fertilizer response in tuber crops. Furthermore, the enhanced vine diameter under lime + compost + biochar treatment application suggests structural and biochemical improvements. This aligns with findings by Sika and Hardie (2014), who reported that biochar improves soil physical properties and root proliferation when co-applied with organic matter.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 3: Effect of treatments application on growth parameters of sweet potato\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"612\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eNo. of branches\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eNo. of leaves\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003eVine diameter \u0026nbsp;(cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eVine length (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e72.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e103.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eBiochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e83.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e92.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eCompost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e62.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e96.40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e99.87 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e92.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eNPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e51.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e67.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime + Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e80.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e107.90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime + Compost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e60.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e98.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime + NPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e71.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e188.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime + Compost + \u0026nbsp;Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e2.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e91.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e107.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eLime + Compost + Biochar + NPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e3.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003e82.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e92.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 234px;\"\u003e\n \u003cp\u003eSED\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 84px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 115px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eNS: not significant, No.: Number, cm: centimeter\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAs presented on table 4, the response of sweet potato to various soil fertility treatments revealed that integrated inputs had more positive significant on storage root development compared to individual amendments. The combined treatment application of lime + compost + biochar produced the highest storage root yield (10.00 t/ha) compared to all other treatments applied. This attributed to improved soil pH, enhanced microbial activity and better moisture and nutrient retention reported by Sika and Hardie (2014). Also, the treatment application of lime + biochar yielded the highest number of storage roots per hectare, highlighting the potential of biochar to boost tuber formation when combined with soil lime. Lehmann and Joseph (2015) noted that biochar amendments can enhance root proliferation and reduce nutrient leaching, particularly in sandy and acidic soils.\u003c/p\u003e\n\u003cp\u003eTable 4: Effect of treatment applications on yield of sweet potato\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"623\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003eStorage root weight (t/ha)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003eNo. of storage root/ha\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e5.33\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e33,333\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eBiochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e5.39\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e38,300\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eCompost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e6.61\u003csup\u003ec\u003c/sup\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e46,667\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e7.72\u003csup\u003eb\u003c/sup\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e35,000\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eNPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e5.83\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e46,667\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e8.56\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e51,667\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e5.89\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e40,000\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + NPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e5.83\u003csup\u003ecd\u003c/sup\u003e\u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e46,667\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost + \u0026nbsp;Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e38,333\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost + Biochar + NPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e6.28\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e40,000\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eSED\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 186px;\"\u003e\n \u003cp\u003e0.4296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 197px;\"\u003e\n \u003cp\u003e2.188\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Means followed by the same letter in a column are not significantly different by DMRT at (P\u0026lt;0.005)\u003c/p\u003e\n\u003cp\u003eTable 5 below shows that the protein content of sweet potato studied ranged from 3.90 to 4.57% on dry weight. These values are in the same range of 3.28 to 4.16% obtained by (Ukom \u003cem\u003eet al\u003c/em\u003e., 2009) except for treatment lime + compost + biochar + NPK 15:15:15 and biochar. The ash content varied from 1.07 to 1.80% which is closely around the range of values 0.40 to 2.35% reported by (Eleazu and Eleazu, 2012; Eleazu and Ironua, 2013; Ellong \u003cem\u003eet al.,\u003c/em\u003e 2014). However, sole application of lime had the lowest fat content while control had the highest fat content. There was significant difference in fat content among the treatment applied. The fat contents were lower than the values reported by (Ishida \u003cem\u003eet al.,\u003c/em\u003e 2000). Fat is involved in the insulation of the body organs and in the maintenance of the body temperature and cell function. Crude fiber content as presented in the table varied from 1.24 to 1.49% in dry weight basis. The dry matter content was observed that it ranges from 90.80 to 92.50%. This also shows that all the ten treatments had similar dry matter content values. This result supports the findings of Ellong \u003cem\u003eet al.\u003c/em\u003e (2014). The moisture content values were between 7.50 to 9.20% which were within the range values reported by (Ukom \u003cem\u003eet al\u003c/em\u003e., 2009). For carbohydrate, lime + compost had the highest carbohydrate content while sole application of biochar had the lowest carbohydrate content. These results are in support of the findings of (Ukom \u003cem\u003eet al.,\u003c/em\u003e 2009).\u003c/p\u003e\n\u003cp\u003eTable 5: Proximate composition of sweet potato under the influence of treatments application\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"690\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003eCP %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003eAsh %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003eFat %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003eCF %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003eD M%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003eMC %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eCHO %\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.26b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.80c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.49a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.15d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e84.69d\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eBiochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.57a \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.07a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.30 \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.26e \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.61 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.39c \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e83.68i\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eCompost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.08cd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.17bc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.24e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.40c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e84.77c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e3.98de\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.40b \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.46ab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.75 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.25cd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e84.85h\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eNPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.03cde\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.20bc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.29 \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.29de\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e90.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e9.20a \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e83.99g\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime + Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.05cd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.10c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.35cde\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e90.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e9.20a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e83.97g\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime + Compost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e3.90e \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.16bc \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.28 \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.30de\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e92.50 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e7.50e \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e85.86a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime + NPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.15bc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.14c \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.29 \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.43bc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.66 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.34cd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e84.58a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime + Compost + \u0026nbsp;Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.10cd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.17bc \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.30 \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.40bce\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e90.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e9.18a \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e83.85e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eLime + Compost + Biochar + NPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e4.22b \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e1.14c \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.28 \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1.34cde\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e91.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e8.75b \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e84.27f\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 222px;\"\u003e\n \u003cp\u003eSED\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 53px;\"\u003e\n \u003cp\u003e0.1403\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 56px;\"\u003e\n \u003cp\u003e0.2218\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e0.1126 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.223\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.2188\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.01377\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMeans followed by the same letter in a column are not significantly different by DMRT at (P\u0026lt;0.005)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCP = Crude protein, CF = Crude fiber, MC = Moisture content, CHO = Carbohydrate, DM = Dry matter, NS = Not significant\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAs presented on table 6, the Nitrogen use efficiency (NUE), Phosphorus use efficiency (PUE) and Potassium use efficiency (KUE). Increase in leaf nutrient concentrations of sweet potato can be related to soil quality improvement, nutrient release into the soil solution, increase in soil chemical properties and balanced nutrition of plants. According to (Farrar \u003cem\u003eet al\u003c/em\u003e., 2019), biochar-based fertilizer application has been observed to increase growth and uptake of N, P and K and also, compost application has been found to increase the uptake of N, P and K. Furthermore, acidic soils with Al saturation seriously limit sweet potato yield (Ila\u0026rsquo;ava \u003cem\u003eet al\u003c/em\u003e., 2000), therefore, application of lime alongside enriched biochar has positively increase the NUE, PUE and KUE of sweet potato leaves amongst other treatments.\u003c/p\u003e\n\u003cp\u003eTable 6: Effect of treatments on the Nutrient Use Efficiency of sweet potato leaves\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"510\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eNUE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003ePUE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003eKUE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.07fg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e41.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e6.11bc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eBiochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3.21d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e43.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e5.83c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eCompost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.17f\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e35.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e5.29c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3.8d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e87.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e16.25a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eNPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.72e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e35.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e4.74c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime + Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e4.89ab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e83.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e10.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime + Compost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.91g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e37.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e6.73bc\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime + NPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3.2d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e35.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e5.18c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime + Compost + \u0026nbsp;Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e6.21a\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e96.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e19.05a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eLime + Compost + Biochar + NPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e4.49c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e57.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e5.71c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 257px;\"\u003e\n \u003cp\u003eSED\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.0765\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp\u003e0.01917\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e1.580\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMeans followed by the same letter in a column are not significantly different\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eby DMRT at (P\u0026lt;0.005)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNUE: Nutrient Use Efficiency, PUE: Phosphorus Use Efficiency, KUE: Potassium Use Efficiency.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAs shown on table 7 below, the effect of profitability index of sweet potato production using ten treatment applications which was carried out in order to assess the cost and profit implication of each treatment applied. The total cost for each treatment on table 7 was done by adding up all expenses in Nigeria naira (₦) from land acquisition to harvesting of tubers and also transporting of harvested tubers to the farm gate was calculated. Here, treatment three (NPK 15:15:15) had the highest total expenditure whereas, it didn\u0026rsquo;t give the highest profitability index. Gross profit was calculated by multiplying 1 kg (which was ₦200.00 as at when this research work was carried out) value price of sweet potato by tuber weight. However, the profitability index is thus, calculated as the gross profit divided by the total cost which connotes that for every ₦1 spent, there is a corresponding monetary value in ₦ gained as profit. Treatment combination of lime + Compost + biochar gave the highest profitability index of 3.51. I.e., ₦1 spent on treatment combination of lime + compost + biochar gave a profit of ₦3.51 in return, while NPK 15:15:15 gave the lowest profitability index.\u003c/p\u003e\n\u003cp\u003eTable 7: Effect of profitability index of sweet potato\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"623\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003eYield (t/ha)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003eTotal cost (₦)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eGross profit (₦)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e434,166\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e760,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eBiochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e550,816\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,078,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eCompost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e626,166\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,232,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.97\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e7.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e538,406\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,544,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eNPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e654,166\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,266,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.63\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e8.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e543,611\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,711,200\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3.15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e580,286\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,178,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + NPK 15:15:15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e5.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e595,286\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,166,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e1.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost + \u0026nbsp;Biochar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e570,463\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e2,000,000 \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e3.51\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 240px;\"\u003e\n \u003cp\u003eLime + Compost + Biochar + NPK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e6.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e591,389\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e1,256,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e2.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eP.I.: Profitability Index\u003c/em\u003e\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eFrom the results obtained in this research, it is evident that the applied treatments did not have significant influence on the growth of sweet potato in the study area, also, enriched biochar did not influence proximate compositions of sweet potato storage roots while liming enriched biochar gave better yield of sweet potato than other treatments applied. It is, therefore, concluded that organic fertilizer should be used to increase sweet potato storage roots quantity and quality. However, further studies need to be carried out to ascertain the residue impact of biochar on sweet potato production.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e: O.A.A. Conceived and designed the project. E.AA. and D.O. supervised the research work and provided guidance throughout the study. A.A.A. and R.M.A. were responsible for materials preparation and methodology implementation. A.G.G. and O.S.Y. carried out the laboratory analysis. O.A.A. wrote the introduction and Results sections. E.A.A. and D.O. critically reviewed and edited the manuscript. All authors read and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Statement:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study did not involve human participants, animal subjects, or endangered plant species. The sweet potato vine used in the experiment was obtained from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria. The plant material was cultivated and legally sourced; no wild collection was involved, and therefore no special permits, licenses, or ethical approvals were required for its use in this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e No funding was received for conducting this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics, Consent to Participate, and Consent to Publish:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe plant used in this study was Ex-Igbariam, a cultivated type pirchased from the National Root Crops Research Institute (NRCRI), Nigeria. Vine cuttings were selected as the planting material in line with local or national guidelines.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePermissions to collect the plants/plant parts:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo special permissions or licenses were required for the collection of plant material used in this study. The vines were purchased from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria, a recognized and authorized institution for the distribution of certified planting materials. The use of cultivated vines obtained through legal purchase does not require additional collection permits, as the material was not sourced from the wild or protected areas.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAdekiya, A.O.; Agbede, T.M.; Olayanju, A.; Ejue, W.S.; Adekanye, T.A.; Adenusi, T.T.; Ayeni, 2020. amendment: Impact on chemical properties and corn nutrient uptake in a Podzol. Can. J. and wood-based biochars. Geoderma 2021, 397, 115100.\u003c/li\u003e\n \u003cli\u003eAgele, S. O., Ajayi, A. E., \u0026amp; Iremiren, G. O. (2017). Growth and yield response of sweet potato (Ipomoea batatas L.) to different soil fertility management practices in a rainforest zone of Nigeria. African Journal of Agricultural Research, 12 (24), 2061\u0026ndash;2069. https://doi.org/10.xxxx/ajar.v12i24\u003c/li\u003e\n \u003cli\u003eAssociation of Official Analytical Chemists. (2005). Official methods of analysis of AOAC International (18th ed.). AOAC International\u003c/li\u003e\n \u003cli\u003eChude, V. O., Olayiwola, S. O., Daudu, C., \u0026amp; Ekeoma, A. (2012) Fertilizer use and management practices for crops in Nigeria (4th ed.). Federal Fertilizer Department, Federal Ministry of Agriculture and Rural Development\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eEleazu and Ironua, 2012 C.O. Eleazu, C. Ironua. Physiochemical composition and antioxidant dynamics in acidic soil. J. Agric. Resour. Environ. 2017, 34, 47\u0026ndash;53.\u003c/li\u003e\n \u003cli\u003eEllong, E. N., Billard, C., \u0026amp; Adenet, S. (2014). Comparison of physicochemical, organoleptic and nutritional abilities of eight sweet potato (Ipomoea batatas) varieties. Food and Nutrition Sciences, 5(2), 196\u0026ndash;211. https://doi.org/10.4236/fns.2014.52025\u003c/li\u003e\n \u003cli\u003eFarrar, M. B., Wallace, H. M., Xu, C.-Y., Joseph, S., Dunn, P. K., Nguyen, T. T. N., \u0026amp; Bai, S. H. (2019). Biochar co-applied with organic amendments increased soil-plant potassium and root biomass but not crop yield. Journal of Soils and Sediments, 20(2), 113\u0026ndash;119. https://doi.org/10.1007/s11368-020-02846-2\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eFood and Agriculture Organization of the United Nations. (2020). FAOSTAT: Crops and livestock products. FAO. https://www.fao.org/faostat/en/#data/\u003c/li\u003e\n \u003cli\u003eIla\u0026rsquo;ava V.P., Blamey P. and Asher C.J. 2000. Effects of lime and gypsum on growth of sweet potato in two strongly acid soils. Australian Journal of Agricultural Research 51, 1031\u0026ndash;1037.\u003c/li\u003e\n \u003cli\u003eJ.F. Effect of Biochar on Soil Properties, Soil Loss, and Cocoyam Yield on a Tropical Sandy loam Alfisol. Sci. World J. 2020, 9391630 cocoyam. John wilsey and Sons, New York, 234pp.\u003c/li\u003e\n \u003cli\u003eJoseph, S.; Pow, D.; Dawson, K.; Rust, J.; Munroe, P.; Taherymoosavi, S.; Mitchell, D.R.G.; Robb, S.; Solaiman, Z.M. 2020. Biochar increases soil organic carbon, avocado yields and economic return over 4 years of cultivation. Sci. Total Environ. 724, 138153.\u003c/li\u003e\n \u003cli\u003eLehmann, J., \u0026amp; Joseph, S. (Eds.). (2015). Biochar for environmental management: Science, technology and implementation (2nd ed.). Routledge. https://doi.org/10.4324/9780203762264\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eMukhopadhyay, S. K., Banker, G. J., \u0026amp; Patel, R. M. (2011). Influence of nutrient management on vegetative vigor and flowering in tuberose (Polianthes tuberosa L.). Journal of Horticultural Science, 6 (2), 112\u0026ndash;117.\u003c/li\u003e\n \u003cli\u003ePiash, M.I.; Iwabuchi, K.; Itoh, T.; Uemura, K. (2021). Release of essential plant nutrients from manure- and wood-based biochars. Geoderma 397, 115100. Solaiman, Z.M.; Shafi, M.I.; Beamont, E.; Anawar, H.M. (2020). Poultry litter biochar increases mycorrhizal colonisation, soil fertility and cucumber yield in a fertigation system on sandy soil. Agriculture. 10, 480.\u003c/li\u003e\n \u003cli\u003eRahimizadeh, M., Kashani, A., Zare-Feizabadi, A., Koocheki, A. R., \u0026amp; Nassiri-Mahallati, M. (2010). Nitrogen use efficiency of wheat as affected by preceding crop, application rate of nitrogen and crop residues. Australian Journal of Crop Science, 4, 363\u0026ndash;368. https://www.researchgate.net/publication/266456514\u003c/li\u003e\n \u003cli\u003eRees, D., van Oirschot, Q., \u0026amp; Amour, R. (2001). The role of sweet potato in food security and income generation for resource-poor farmers. Outlook on Agriculture, 30(2), 131\u0026ndash;136. https://doi.org/10.5367/000000001101293424\u003c/li\u003e\n \u003cli\u003eRyan, J., Rashid, A., \u0026amp; Matar, A. (2018). Organic amendments and soil management strategies for mitigating soil acidity. Journal of Soil and Water Research, 13, 85\u0026ndash;92.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSika, M. P., \u0026amp; Hardie, A. G. (2014). Effect of pine wood biochar on ammonium nitrate leaching and availability in a South African sandy soil. European Journal of Soil Science, 65, 113\u0026ndash;119. https://doi.org/10.1111/ejss.12082\u003c/li\u003e\n \u003cli\u003eSmyth, A. J., \u0026amp; Montgomery, R. F. (1962). Soils and land use in Central Western Nigeria. Ibadan University Press.\u003c/li\u003e\n \u003cli\u003eSyuhada, A.B.; Shamshuddin, J.; Fauziah, C.I.; Rosenani, A.B.; Arifin, 2016. A Biochar as soil amendment: Impact on chemical properties and corn nutrient uptake in a Podzol. Can. J. Soil Sci., 96, 400\u0026ndash;412.\u003c/li\u003e\n \u003cli\u003eTewe, F.E. Ojeniyi, O.A. Abu (2003). Sweet potato Production, Utilization and Marketing in \u0026nbsp; \u0026nbsp;Nigeria. Social Science Department International Potato Center (CIP), Lima, Peru. Pg.19-36 tubersum L.) and green mass of fodder sunflower (Helianthus annuus L.).\u003c/li\u003e\n \u003cli\u003eUkom, A. N., Ojimelukwe, P. C., \u0026amp; Okpara, D. A. (2009). Nutrient composition of selected sweet potato (Ipomoea batatas L. Lam) varieties as influenced by different levels of nitrogen fertilizer application. Pakistan Journal of Nutrition, 8(11), 1791\u0026ndash;1795. https://doi.org/10.3923/pjn.2009.1791.1795\u003c/li\u003e\n \u003cli\u003eUkom, A., Ojimelukwe, P. C., and Okpara, D. (2009). Nutritional composition of selected sweet potato. Pakistan journal of Nutrition, 8 (11), 1791 \u0026ndash; 1795.\u003c/li\u003e\n \u003cli\u003eUllah, Z.; Akmal, M.; Ahmed, M.; Ali, M.; Jamali, A.Z. (2021) Effect of biochar on soil chemical properties and nutrient availability in sandstone and shale derived soils. J.Biol. Environ. Sci. 2018, 12, 96\u0026ndash;103. Available online: http://www.innspub.net\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eWang, M.; Jiang, X.-J. (2017). Effects of applying lime and calcium montmorillonite on nitrification dynamics in acidic soil. J. Agric. Resour. Environ. 34, 47\u0026ndash;53.\u003c/li\u003e\n \u003cli\u003eXuan, W.; Xiong, W.; Huang, T.; Ran, W.; Li, D.; Shen, Q.; Li, Q.; Zhang, R.2016 (2016). Swine manure and quick lime have different impacts on chemical properties and composition of bacterial communities of an acidic soil. Appl. Soil Ecol. 100, 38\u0026ndash;44.\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":"Biochar, Lime, organic fertilizer, soil fertility","lastPublishedDoi":"10.21203/rs.3.rs-7223632/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7223632/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSweet potato is one of the most important roots and tuber crop in terms of food security and its nutritional values. Over the years, the growth and yield of sweet potato is constrained by poor soil fertility and most farmers have adopted the use of inorganic fertilizers which has been known to acidify the soil. In recent years, farmers have increasingly adopted biochar as a targeted solution to mitigate this challenge, but due to its slow release of nutrients, it needs to enriched in order to increase the nutrients release to plant. Thus, this study is to evaluate the effect of enriched biochar on the growth, yield and proximate composition of sweet potato.\u003c/p\u003e\u003cp\u003eThis study was carried out at the NIHORT, Ibadan, Nigeria, where field experiment involved ten treatments; lime, NPK 15:15:15, compost and biochar sole, combined treatment combinations laid in a randomized complete block design with three replicates. There were a total of 30 plots with 6 m\u0026sup2; per plot size and data were collected on growth and yield parameters. Treatments had no significant effect on the growth parameters. However, lime\u0026thinsp;+\u0026thinsp;biochar\u0026thinsp;+\u0026thinsp;compost gave higher tuber weight of 10 t/ha compared to other treatments applied. Also, the treatment combination; lime\u0026thinsp;+\u0026thinsp;biochar\u0026thinsp;+\u0026thinsp;compost increased the leaf nutrient concentrations of sweet potato. Further studies should be carried out to determine the residual effect of the enriched biochar on growth and yield of sweet potato.\u003c/p\u003e","manuscriptTitle":"Influence of Enriched Cassava Peel Biochar on Growth, Yield and Proximate Composition of Sweet Potato","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-01 12:12:58","doi":"10.21203/rs.3.rs-7223632/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":"646459e4-0dee-4e6d-b1ca-91369f470b99","owner":[],"postedDate":"October 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-12T10:09:03+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-01 12:12:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7223632","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7223632","identity":"rs-7223632","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}