Effects of exogenous self-made active humic acid manure on physical and chemical properties and soil bacteria of continuous cropping obstacle soil in Capsicum annuum L

Abstract Aims Capsicum annuum L. is a widely cultivated horticultural crop known for its pungent varieties and culinary significance. However, the production of chili pepper has been hindered by soil continuous cropping obstacles. Methods In this study, we investigated the potential of differential fertilizer application, specifically the combination of homemade humic acid organic fertilizer, compound fertilizer, and Bacillus subtilis, in improving soil conditions and microbial activity to alleviate the soil continuous cropping obstacles in chili pepper cultivation. The experiment focused on evaluating the effects of the differential fertilizer application on soil physicochemical properties, including electrical conductivity and enzyme activities (urease, hydrogen peroxide, phosphatase, and sucrase), as well as cation exchange capacity. Additionally, the microbial community in the soil was also examined. Results The application of the differential fertilizer significantly improved soil conditions. The electrical conductivity was reduced, indicating a decrease in soil salinity. Enzyme activities, such as urease, hydrogen peroxide, phosphatase, and sucrase, exhibited increased levels, suggesting enhanced nutrient cycling and availability. Moreover, the cation exchange capacity was unaffected by the differential fertilizer application. Microbial analysis revealed positive changes in the soil microbial community, indicating a potential improvement in soil health. Conclusions These findings highlight the effectiveness of the differential fertilizer application, consisting of homemade humic acid organic fertilizer, compound fertilizer, and Bacillus subtilis, in mitigating soil continuous cropping obstacles in chili pepper cultivation. The improved soil conditions and enhanced microbial activity contribute to the sustainability and productivity of chili pepper production.