Abstract: Soil nematodes are an important part of underground community and play a crucial role in ecosystem energy flow and material cycling. Elevated nitrogen (N) deposition and precipitation regime alteration are two major forms of global change, which affect soil nematodes. Nitrogen deposition has adverse effects on soil nematodes, while precipitation alteration might affect the responses of nematodes to N deposition. To investigate how precipitation regime alteration affects the resistance of soil nematode community to N deposition can help understand the response of soil nematodes to climate change. In this study, we conducted an 8-year manipulative field experiment comprising precipitation addition (totaling 80 mm, with varied precipitation frequency and intensity) and N addition in a temperate steppe of Inner Mongolia. There were five precipitation intensities (2, 5, 10, 20 and 40 mm), and two N addition levels (N10: 10 g N·m^-2·a^-1; N0: control). The response of soil nematode resistance to N deposition under different precipitation addition intensities was quantified by the resistance of soil nematode abundance and diversity. The results showed that the resistance of bacterivore nematode abundance to N deposition was the highest under 40 mm precipitation addition intensity among all precipitation addition intensities. The resistance of fungivore abundance to N deposition was higher under low precipitation intensity. The resistance of predator-omnivore nematode abundance to N deposition was higher under high precipitation intensity than under the moderate precipitation intensity. The resistance of plant parasitic nematode abundance to N deposition reached its peak under low precipitation intensity. Moreover, the resistance of evenness, trophic diversity, and Shannon diversity to N deposition was significantly higher under low precipitation intensity than other treatments. Changes in soil moisture and pH induced by precipitation regime alterations are the main factors affecting soil nematode community.

Key words: soil nematode, resistance, precipitation intensity, nitrogen deposition