Influence of enriched corn cob biochar on soil properties and yield of peanut (Arachis hypogaea L.) and bush sitao (Vigna unguiculata L.)

In the search for alternative and sustainable inputs for agricultural production, biochar has been shown to improve soil quality and eventually lead to improved crop productivity. Enrichment of biochar with chemical fertilizers is an innovative way to further explore the benefits that it can offer on the soil- plant-environment system. A pot experiment was conducted to investigate the influence of enriched corn cob biochar on the growth and yield of bush sitao and peanut; and the changes in chemical properties of an acidic sandy loam soil (Cumulic Hapludolls). The study was performed at the screen house of the Agricultural Systems Institute, College of Agriculture and Food Science, U.P. Los Baos' [Philippines] screen house from November 15, 2023 to February 15, 2024. After the bush sitao cropping, the soil pH across treatments has increased to near neutral levels from the initial soil pH of 5.95 and potassium levels were enhanced in the treatments (ranging from 0.80 cmol/kg 0.84 cmol/kg) compared to 0.14 cmol/kg of the control treatment. Improved N content was recorded in the enriched CCBC treatments (ranging from 0.11% 0.81%) against 0.08% in the initial soil. The highest OM content was recorded in the 2.5 tons/ha FECCBC + microbial inoculant treatments; while the P levels were comparable. A higher bacterial and endomycorrhizal count was recorded in the 5 tons/ha compost + 5 tons/ha CCBC, resulting in higher plant and root fresh weight of bush sitao. The growth traits and development of bush sitao showed a significantly higher chlorophyll content in the 5tons/ha FECCBC at 50 DAS. The macronutrient uptake of bush sitao plant biomass has reacted well in the 2.5 tons/ha FECCBC + microbial inoculant treatment. while the 5 tons/ha raw CCBC produced a significantly higher number and weight of nodules of bush sitao. The peanut study reflected an enhanced soil pH (6.05-6.90), OM content (1.62%- 1.99%) and endomycorrhizal count (81-109) in the treatments compared to the initial soil. Comparable results were recorded among treatments in terms of the macronutrient levels. The highest bacterial count was observed in the 2.5 tons/ha FECCBC + MI with 8.2x10 sub 6 cfu/g soil compared to 4.7x10 sub 6 in the initial soil. The plants in the 5 tons/ha FECCBC produced significantly greener plants and higher values on macronutrient uptake in the plant and root biomass, resulting in a higher weight of marketable pods, and dry matter weight of the plant and roots. The 5 tons/ha raw CCBC produced a significantly higher number of nodules.