Enhancing soil quality and nematode diversity through sustainable tillage and organic fertilization in the Loess Plateau's semi-arid farmlands

Abstract

To explore the impact of tillage and fertilization practices on enhancing the soil micro-ecological environment in the dry farmlands of the Loess Plateau, this study used nematodes as indicator organisms. We investigated the effects of three tillage methods (deep tillage, subsoiling, and no-tillage) and four fertilization methods (no fertilization, full chemical fertilizer, 50 % organic fertilizer substituting chemical fertilizer, and full organic fertilizer) on the soil nematode community and its functions. Our findings indicate that the interaction between tillage and fertilization significantly influenced the soil's total abundance of nematodes and trophic groups. Specifically, the total abundance of nematodes and the relative abundance of bacterial-feeding nematodes were higher under subsoiling in maize and no-tillage in wheat season. Moreover, the energy flux within the food web was more pronounced. Applying chemical fertilizers resulted in greater soil bulk density and a higher proportion of plant parasitic nematodes than other treatments, harming the diversity of soil nematode communities. The nematode community's abundance was positively correlated with alkali-hydrolyzable nitrogen content. In summary, reducing tillage in the wheat-maize annual rotation system, implementing subsoiling in the maize season and no-tillage in the wheat season, combined with organic fertilizer application, can improve soil quality, improve nematode community structure and maintain the stability of the soil food web. This approach positively contributes to improving soil health and ecological stability in the dry farming regions of the Loess Plateau.