The productivity of sandy tropical soils may be enhanced through the application of composted organic materials. This study investigates the effects of composted mixtures of brewery spent grain (BSG) and animal manures on the growth of green amaranth (Amaranthus caudatus L) under field conditions. Composted treatments included BSG mixed with poultry droppings (PD) or cattle dung (CD) in volumetric ratios of 1:1 and 2:1 prior to composting, resulting in four compost variants: BSG+PD(1:1), BSG+PD(2:1), BSG+CD(1:1), and BSG+CD(2:1). Additionally, composted BSG alone served as a reference. Each amendment was added at 20 t ha-1 , alongside an un-amended control for comparative purposes. Growth and yield assessments conducted four weeks post-sowing revealed that not all amended treatments outperformed the control. Notably, the BSG+PD(1:1) treatment consistently increased total biomass (fresh and dry matter yields by approximately 143% and 58%, respectively) as immediate effects, and significantly more (184% and 108%, respectively) as residual effects when compared to the control. Leaf yields under this treatment showed increases of 173-177% (immediate effects) and 122-125% (residual effects). These variations in amaranth growth and yield were primarily attributed to improvements in soil exchangeable calcium (Ca) and total nitrogen (N) content due to the compost application. The findings suggest that a composted equal-volume mix of BSG and PD may serve as an effective organic amendment for enhancing the yield of short-duration leafy vegetables like amaranth in coarse-textured soils of the humid tropics.

Improving the fertility status of nutrient-depleted soils is critical to achieving food security. The negative effects of chemical fertilizers on soils necessitate the global quest for eco-friendly, effective, and sustainable alternatives. This work assessed the effect of black soldier fly (BSF) residue application on soil properties and watermelon growth. The study was set up in a completely randomized design with six replications. The treatments were BSF1 (BSF applied at 10 t ha⁻¹), BSF2 (20 t ha⁻¹), BSF3 (30 t ha⁻¹), and control. The plant data collected in this study were vine length, leaf width, number of leaves, and stem girth, and the soil’s physicochemical properties were determined. The results show that BSF residue-treated soils had 20.4–49.5% higher aggregate stability and 50–160% higher hydraulic conductivity than the control treatment. BSF residue-treated soils had significantly (p ≤ 0.05) higher pH, total N, available P, exchangeable K, and organic carbon than the control treatment. BSF3 treatment had the highest effect on available P and soil pH relative to other amended treatments. High rates of BSF residue application did not significantly increase the total available N and P contents, which could suggest that BSF application at 30 t ha⁻¹ may not pose a risk of N and P pollution to water systems. BSF residue-treated soils improved (p < 0.05) watermelon growth parameters relative to the control. Watermelon leaf length was significantly (p ≤ 0.05) longer for BSF residue-treated soils than the control treatment. A similar trend was observed for the number of leaves, leaf width, and stem girth. At 4, 6, and 10 weeks after sowing, BSF residue-treated plants had 38.2–104%, 22.7–118%, and 25.7–103% longer vine lengths than the control treatment, respectively. The study results suggest that BSF residue application can enhance the fertility status of a coarse-textured ultisol for watermelon production.

Agriculture remains a cornerstone of economic development, food security, and the livelihoods of rural communities in sub-Saharan Africa. This study employed a parametric evaluation approach to assess the suitability of soils in the Nsukka Local Government Area (LGA) of Enugu State, Southeastern Nigeria, for cultivating maize (Zea mays) and Cassava (Manihot esculenta) using the Geographical Information System (GIS). The study applied the FAO land evaluation framework using systematic soil sampling, laboratory analyses, and GIS mapping. A total of thirty geo-referenced soil samples from the surface (0-20 cm) were gathered in triplicate across Nsukka LGA. Climatic and topographic data were integrated with soil parameters to assess suitability. Thematic maps were developed and overlaid to generate suitability classes for maize and cassava using the ArcGIS software. The climate characteristics were highly suitable for crop production. Topography (slope) and soil characteristics (texture, organic carbon, and base saturation) were the most limiting factors for both crops. The maps showed that 6.18% of the study region was highly suitable, while 93.82% was moderately suitable for maize production. The study region was entirely suitable for cassava cultivation. These results support the recommendation for crop-specific land-use planning and targeted soil management practices to improve maize productivity and leverage cassava's resilience in marginal soils.

Low soil fertility is a challenge that affects tomato production among farmers in Nsukka, Southeast Nigeria. To overcome this challenge, a greenhouse study at the Department of Soil Science, University of Nigeria, Nsukka evaluated the residual effects of black soldier fly larvae waste (BSFLW) application on soil chemical properties and tomato performance. The experiment was arranged in a complete randomised design. The treatments, BSFLW10 (BSFLW applied at 10 t ha-1), BSFLW20 (20 ha-1), BSFLW30 (30 ha-1), 400 kg ha-1NPK 15:15:15 and Control, were replicated five times. The test soil (0-15cm) was dried, sieved and weighed 5 kg into potting bags. Afterwards, tomato seedlings were transplanted into the treated pots. Results show that BSFLW-treated pots had 2-15.5%, 23-39%, 14.7-58.8% and 33.7-44.8% higher soil pH, total N, available phosphorus and organic carbon than the control pot, respectively. Treatments application significantly (p ≤0.05) enhanced tomato growth and yield. The treated soil had 37.4-55.6%, 49.7-73.9%, and 53.4-65.1% higher number of leaves and fruits, and fruit weight than the control, respectively. The BSFLW application has promising effects on soil properties and tomato performance. Further field studies are needed to evaluate the effects of BSFLW application on soil properties and tomato performance before r recommend appropriate application rate to farmers.

A two-year field experiment was conducted in 2018 and 2019 at the Teaching and Research Farm, Faculty of Agriculture, University of Nigeria, Nsukka, Southeastern Nigeria, to evaluate the effects of organic and inorganic fertilizer combinations and carrot genotypes on seedling emergence, growth, and yield of carrot (Daucus carota L.). The experiment was a 5 × 3 factorial arranged in a randomized complete block design with four replications. Five fertilizer treatments comprised control, 20 t/ha poultry manure, 20 t/ha pig manure, 10 t/ha poultry manure + 200 kg/ha NPK 15:15:15, and 10 t/ha pig manure + 200 kg/ha NPK 15:15:15. Three genotypes, Safety Touchon France, Carotte Touchon AM, and Carotte Touchon ETS, were evaluated. In 2018, fertilizer treatments significantly affected seedling emergence, harvest index, whole-plant biomass yield, and root yield. The application of 10 t/ha poultry manure + 200 kg/ha NPK produced the highest whole-plant biomass yield (6.0 t/ha), root yield (3.5 t/ha), harvest index (65.4%), and marketable yield (97.0%). In 2019, 20 t/ha poultry manure produced the highest whole-plant biomass yield (8.5 t/ha), root yield (5.7 t/ha), and harvest index (67.5%). Genotypic effects were generally limited, although significant differences occurred for selected traits. Carotte Touchon AM recorded comparatively higher biomass and root yields, while Safety Touchon France produced more harvested roots. Overall, 10 t/ha poultry manure + 200 kg/ha NPK 15:15:15 provided a consistent yield advantage and is recommended for carrot production under the study conditions.