Dynamics of soil nematode communities in wheat fields under different nitrogen management in Northern China Plain

The temporal dynamics of nematode abundance and community composition were monitored in a nitrogen (N) fertilization experiment during the main growth stages of winter wheat in Northern China Plain. A randomized complete block design was used with four levels of N fertilization (50, 100, 150 and 300 kg N ha−1 y−1 denoted as N1, N2, N3 and N4, respectively). The results showed that winter wheat aboveground biomass increased but soil pH decreased with elevating N fertilization. Total nematode abundance reached the highest values at the shooting stage of wheat, and was significantly increased by the N fertilization. On the contrary, nematode generic richness declined with increasing N fertilization. The relative abundance of bacterivores showed minor changes among different fertilization treatments whereas that of fungivores was suppressed by the N4 treatment. Plant parasites were the most abundant under the N2 treatment. The relative abundance of omnivores–predators declined with increasing N fertilization. The results indicate that trophic groups have distinctive responses to different levels of N fertilization, and N fertilization may induce an abundant but simple nematode community in the winter wheat field of North China Plain. Our findings also highlight the potential of adequate N application to reduce plant parasites and to control agriculture pests.