Biochar Boosts Pepper Yield and Soil Health in Protected Continuous Cropping Systems in China

Protected cultivation of pepper in southern China’s red soil region often leads to soil degradation and continuous cropping obstacles. To investigate whether biochar can alleviate these problems by regulating the soil microenvironment, pot and incubation experiments were conducted from 2021 to 2023 with biochar application rates of 0~10% (w/w). The results showed that appropriate biochar application significantly improved pepper yield and soil quality. Under the 6% biochar treatment, pepper yield and dry matter accumulation increased by 89.05% and 36.79%, respectively, compared to the control. Soil bacterial and fungal abundances increased by 346.61% and 107.37%, and their OTU numbers rose by 64.13% and 35.15%, respectively. Biochar application also elevated soil pH, organic matter, available potassium, and total nitrogen contents, improved aggregate stability, and enhanced the activities of urease, catalase, sucrase, and acid phosphatase. Furthermore, biochar altered the rhizosphere microbial community structure and increased bacterial diversity. These findings demonstrate that biochar can promote pepper growth by improving soil physicochemical properties, enzyme activities, and microbial community structure, providing a viable strategy for mitigating continuous cropping obstacles in protected cultivation.