Mowing did not mitigate the negative effects of nitrogen deposition on soil nematode community in a temperate steppe

Abstract

Soil nematodes are the most numerous components of the soil fauna in terrestrial ecosystems. The occurrence and abundance of nematode trophic groups determine the structure and function of soil food webs. However, little is known about how nitrogen deposition and land-use practice (e.g. mowing) affect soil nematode communities. We investigated the main and interactive effects of nitrogen addition and mowing on soil nematode diversity and biomass carbon in nematode trophic groups in a temperate steppe in northern China. Nitrogen addition and mowing significantly decreased the abundance of soil nematodes and trophic diversity but had no effects on nematode richness and the Shannon-Wiener diversity. Nitrogen addition influenced soil nematode communities through decreasing soil pH. Mowing influenced soil nematode communities through decreasing soil moisture. Nitrogen addition enhanced the bacterial energy channel but mowing promoted fungal energy channel in the soil micro-food web. Our study emphasizes that ecosystem function supported by soil organisms can be greatly influenced by nitrogen deposition, and mowing cannot mitigate the negative effects of nitrogen deposition on soil food webs.