Alleviating soil degradation caused by green bean continuous cropping: application of combined amendments

Abstract

Context Management practices of conventional cropping that includes intense monoculture has led to soil health problems, such as deterioration of soil fertility and soil microbial diversity, leading to the proliferation of soil-borne diseases. Soil amendments using organic materials, calcium and disinfecting agents may be important management tools to promote healthier soils. Aims To determine the effects of combined soil improving amendments to mitigate problems associated with continuous cropping of green bean. Methods Soil samples were collected from the modified areas (SF) of combined application of organic amendments (biofertiliser, humic acid material), calcium amendments (lime, calcium magnesium compound fertiliser) and disinfection materials (carbendazim) and unmodified areas (CK) to compare the effects of chemical characteristics, allelochemicals and microbial community in soil under different soil modifications. Key results Results showed that combined modification could significantly increase soil pH, organic matter (SOM), available nutrients (N, P, and K), and decrease the contents of phenolic acids allelochemicals in soil. However, l-epicatechin increased. The combined modification could increase the relative abundance of beneficial bacteria such as Actinobacteria, Nocardioides and Streptomyces, and decrease the relative abundance of microorganisms such as Betaproteobacteria, Acidobacteria and Deltaproteobacteria that can cause soil-borne diseases. Conclusions Biological mechanism mapping showed that the application of combined amendments could effectively alleviate soil fertility problems associated with long-term cultivation of green bean. Implications The combined application of organic amendments, calcium amendments and disinfection materials can modify soil to promote the healthier agricultural soils in long-term vegetable growing areas.