Changes in Soil Nematode and Microbial Community in Cucumber Root-Zone Soil Shaped by Intercropping with Amaranth

Intercropping systems often contribute to soil health management including inhibiting root-knot nematode disease. The main purpose of this study was to investigate the potential effect of the cucumber-amaranth intercropping system on soil biota, specifically the nematode and microbial communities. Furthermore, the cucumber root-nematode disease was also evaluated. The study found significant effects of cultivation systems (cucumber-amaranth intercropping and cucumber monocropping) and growing seasons (winter-spring (WS) and autumn-winter (AW)) on both soil nematode and microbial community structures in cucumber root-zone soil. Intercropping resulted in a decrease in the relative abundance of Meloidogyne spp., which was consistent with the observed alleviation of root-knot nematode disease. Bacterivorous nematodes were dominant in the intercropping system. The microbial biomass and community-level physiological profiles (CLPP) were generally higher in the intercropping system. Beta diversity analysis showed that the composition of microbial communities varied widely among the treatments and growth seasons. These findings suggest that intercropping with amaranth can regulate soil biota, leading to decreased incidence of root-knot nematodes (RKNs) diseases.