Afterlife effect of cover crops on soil nematode food web: Implications from the plant ecological strategy

A trait-based approach is adopted to understand the responses of the soil nematode food web following cover crops incorporated into the soil, i.e., afterlife effect of plant. We conducted an in situ microcosm experiment with two cover crops including leguminous Astragalus sinicus L. ( A. sinicus ), characterized by high nutrient content, and gramineous Lolium multiflorum Lam ( L. multiflorum ), characterized by high C and lignin content, representing the acquisitive and conservative side of the economic spectrum, respectively. Furthermore, two incorporation rates were set to represent low and high biomass production of cover crops that could be incorporated into the soil. Soil main microbial groups, nematode food web, and physicochemical properties were analyzed at weeks 4 and 18 after cover crops incorporated into the soil. Results showed that, regardless of time, cover crops affected the abundance and composition of the soil nematode food web. L. multiflorum supported higher nematode abundance and more complex nematode food web than A. sinicus , charactering with higher fungivore/bacterivore, predator/prey, maturity index, and structure index, particularly under the high incorporation rates. In addition, A. sinicus improved much more resource availability (mineral N and dissolved organic C) than L. multiflorum . Together, the quantity and quality of plant residues jointly drive soil food web structure, and a trait-based framework facilitates the mechanical understanding of afterlife effect of plant on soil ecosystems.