Evaluation of nutrient spatial distribution and heavy metal pollution improvement in small-scale farmland under the action of biochar and microbial organic fertilizer

Currently, China is undergoing reforms in its rural land transfer policy. As a traditional agricultural country, the operation and management of small-scale farmland serve as the primary economic source for Chinese farmers. However, small-scale farmland is vulnerable to external influences and lacks sufficient risk-resistance capabilities. Developing a low-cost, long-term improvement model is essential for enhancing small-scale farmland.This paper explores the direct integration of biochar and microbial organic fertilizer into the cultivation process of heavy metal-contaminated farmland. The results indicate that the combined application of biochar and microbial organic fertilizer increased soil fertility by 161 % and enhanced the abundance of the antagonistic Chaetomiaceae by 31.6 %. Geostatistical simulations revealed low variation in soil pH, while fertility and water content exhibited high variability. Furthermore, the partial least squares path model confirmed that biochar and organic fertilizer promote.This study elucidates the improvement mechanisms facilitated by biochar and microbial organic fertilizer, providing valuable insights for the management of small-scale farmland in the context of agricultural reform in China.