Effects Of Fertilization On Soil Nematode Community Composition In The Eastern Tibetan Plateau Alpine Meadow

The object of the study were 43 plots of grassland on different fertilizer were applied under grazing condition in Alpine Wetland Ecosystem Research Station of typical Alpine Meadow of Lanzhou University, no fertilizer, nitrogen fertilizer (5 g·m-2,10 g·m-2,15 g·m-2) and phosphate fertilizer (2 g·m-2,4 g·m-2,8 g·m-2) were applied, study the effects of fertilization on soil nematode community composition. The results showed that after fertilization, soil nematode diversity increased. Maturity index gradient increases with reduced fertilization, nematodes no changes occur with regular fertilization gradient, but in the process a small amount of nitrogen and phosphate lower number of nematodes. And there is no significant difference in the soil nematode diversity index, maturity index and number among the treatments. After fertilization, fungivores and predators soil nematodes decreased, bacterivores soil nematodes increased significantly in 8 g·m-2 treatment in phosphate fertilizer were applied. With the increase of fertilization gradient, among herbivorous, bacterivores and fungivores soil nematodes have such relationships: herbivorous soil nematodes decreased, increasing the number of bacterivores and fungivores soil nematodes; bacterivores soil nematodes decreased, the number of fungivores soil nematodes reduced. When a small amount of nitrogen and phosphate fertilizer processing, lower the number of herbivorous soil nematodes, but higher omnivorous soil nematodes. The number of c-p1 and c-p3 trophic groups increased with gradient of fertilization increase, reducing the number of others. Changes in the type of soil nematode life cycle tends to c-p2 trophic groups, namely short cycle life history and reproduction rate of r strategists. In addition bacterivores soil nematodes, no significant relationship between other groups of soil nematodes and physicochemical soil condition. Our study can get following conclusion, after fertilization, soil nematode maturity index decreased, the number of bacterivores soil nematodes increased, fungivores soil nematodes reduced, bacterivores soil nematodes has advantages after fertilization, fungivores soil nematodes activity is inhibited; soil nematode life history strategies tend to r strategists, this is a response to fertilization caused an increase in soil nutrients; however, not significant relationship between different trophic groups of soil nematodes and physicochemical soil condition. Therefore, soil nematode community composition may be effected mainly by grazing, needs further study.