As the largest group of soil mesofauna, nematodes occupy all consumer trophic levels in soil food webs, and may serve as a proxy for soil food web structure and composition. The present study was conducted in an intensively managed, solar greenhouse vegetable-production system to investigate the effects of nitrogen management on soil nematode communities. We conducted two experimental trials. The first trial was a field survey in vegetable greenhouses with various cultivation histories (1, 2 and ≥5 years) and open grain fields. The second trial was a series of nematode community analyses over four years from a long-term N management experiment with three treatments: NN (no nitrogen input), RN (reduced N fertilization) and CN (conventional N application). In the field survey, we found that soil total N significantly increased with planting age. After one year of cultivation, greenhouse soil had a significantly lower Shannon-Wiener diversity index (H) (1.55) and a higher abundance of root knot nematodes (RKNs) (292 nematodes per 100. g dry soil) compared to the soil in the open fields. With increasing time of cultivation, there were further decreases in H and increases in RKNs with H reaching 1.03 and RKNs 1254 after five or more years of vegetable planting. Analyses of soil nematode community in the N management experiment indicated that the abundance of RKNs significantly decreased by 55.9% to 770 per 100. g dry soil in the RN treatment compared to 1745 per 100. g dry soil in the CN treatment. The maturity index of the soil nematode community was negatively correlated with the amount of N input and soil total N. Further, tomato fruit yield was not affected by reduced N input in the RN treatment in contrast to the CN treatment. Our results clearly demonstrate that reduced N input had two benefits; (1) reducing the risk of nitrate pollution associated with excessive N input, (2) decreasing the abundance of RKNs and improving the soil nematode community for vegetable production systems.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences (miscellaneous)
- Soil Science