Impact of biochar amended with compost and arbuscular mycorrhizal inoculation on soil chemical properties, root colonization, and yield of cowpea (Vigna unguiculata)

Abstract

The use of biochar, compost, and arbuscular mycorrhizal fungi (AMF) provides many opportunities for soil improvement. Hence, it is important to understand their impacts on soil and plant development to optimally exploit their potentials. A screenhouse experiment was conducted to investigate the effect of biochar amended with compost and arbuscular mycorrhizal on soil chemical properties, root colonization, growth, and yield of cowpea. The experiment was laid out in a completely randomized design with control, using different combinations of Gateway compost with two types of biochar; Gliricidia and Panicum maximum,in percentage and at different rates (2.5, 3.0, 3.5, and 4.0 t/ha), with 2, 4, 6 and 8g of mycorrhizal and mineral fertilizer (RD of SSP -60 kg P₂O₅) in combination with mycorrhizal, making 13 treatment combinations replicated 3 times. The results of the investigation revealed that the application of biochar, compost and AMF significantly (p < 0.05) increased the growth and yield parameters of the cowpea plant. The treatment [70% Gateway compost + 30 % Biochar (Panicum maximum) at 3.5 t/ha + 6g mycorrhizal] enhanced root colonization percentage. Biochar amended with compost application remarkably improved total N, soil organic carbon, soil pH, and available P than mineral fertilizer.