ENHANCING SOIL PROPERTIES AND CAPSICUM (CAPSICUM ANNUUM VAR. GROSSUM L.) PRODUCTIVITY THROUGH THE APPLICATION OF RICE STRAW-DERIVED BIOCHAR

Capsicum, often known as sweet pepper (Capsicum annuum var. grossum L.), is becoming more and more popular in Bangladesh as a vegetable. However, a number of obstacles must be overcome for its production to occur, such as limited cation exchange capacity, poor soil fertility, fast mineralization of soil organic matter, and acidity of the soil. These problems are addressed by applying biochar, a carbon-rich biomass made by pyrolysis under low or no oxygen conditions, as a soil amendment. The purpose of this research was to evaluate how applying biochar affected the qualities of the soil and the production of capsicum in the experimental fields of the Soil Science Department at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur 1706. The treatments included T0 (control, no biochar), T1 (2.5 t/ha biochar), T2 (5.0 t/ha biochar), T3 (7.5 t/ha biochar), and T4 (10.0 t/ha biochar). The experiment followed a Randomized Complete Block Design (RCBD) with three replications. Two capsicum genotypes, BU capsicum 1 (G-1) and a capsicum line (G-2), were used as test crops. Biochar application improved soil properties, such as increasing pH, organic carbon (OC), cation exchange capacity (CEC), and the content of nitrogen, phosphorus, and sulfur. Soils amended with rice straw biochar showed significantly higher plant height, fruit number, fruit length, fruit weight, and capsicum yield compared to untreated soils. The most notable improvement in plant growth due to biochar was reflected in the biomass yield. Fruit yield varied significantly, ranging from 54.17 t/ha (T0) to 88.36 t/ha (T2) for G-1 and 92.44 t/ha (T2) for G-2. These findings suggest that converting rice residues into biochar and applying it to soil has significant potential to enhance capsicum production and improve soil health. Farmers are encouraged to apply 5.0 t/ha of rice residue-derived biochar to sustainably increase capsicum yields and improve soil quality.