Studies On The Characteristics Of Soil Nematode Community By Several Different Land Use Types In Jiangsu Province

The species diversity of soil nematodes were investigated under different land use types in Jiangsu province, including farmland, woodland, wetland and mining land. The study with an aim to research the distribution characteristics of soil nematode community under different land use types, for discussing the relationship between soil nematodes and soil environmental factors. Meanwhile, the effects of different key factors on soil nematode communities were also discussed. The soil nematodes may be used to evaluate soil health quality as ecological indicators. The results are as follows:1) During the study, a total of69nematode genera were found in Jiangsu province, belonging to28families,8orders,2classes. In the six agriculture areas, a total of41nematode genera were found, belonging to19families,7orders,2classes.In the five woodland, a total of45nematode genera were found, belonging to22families,7orders,2classes. In the coastal wetland, a total of39nematode genera were found, belonging to20families,8orders,2classes. In the mining area, a total of35nematode genera were found, belonging to15families,5orders,2classes.2) The nematode numbers and nematode community composition were obviously influenced by soil texture, fertilization and tillage practices. In the six agriculture areas, the least nematode numbers were found in Yanjiang agriculture area compared with others, also the total numbers of nematode of other agriculture areas had relatively large difference. And the similar dominant genera of nematode were found in the near location of agriculture areas. Redundancy analysis (RDA) of the relationship between nematode species and soil environmental factors indicated the soil physico-chemical characteristics obviously affected some soil nematode genera.3) The nematode distribution of woodlands indicated that the soil qulity, soil moisture and pH had significant effects on nematode community. The number of soil nematode fluctuated significantly with climatic zones from north to south, also showing an increasing trend which is related with soil moisture and pH. Multivariate analysis on the nematode community data revealed that non-metric multidimensional scaling (nMDS) and analysis of similarities (ANOSIM) were efficient methods to assess soil nematode community structure. The soil nematode community structure had no significantly difference between Dadong mountain and Diyi mountain, but other woodlands were not so.4) The soil nematode abundance, species richness and community diversities had corresponding changes with the succession of vegetations. ANOSIM was performed to test differences for nematode communities under different vegetations, and the soil nematode community structure had significant difference among vegetations. SIMPER was used to identify the dominant nematode genera from the groupings formed ANOSIM analysis, and main contributing species were different under different vegetation belts, In the study, we found the nematode community characteristic between uncultivated vegetations and cultivated vegetation had great changes, also there was a certain correlation between these changes and soil physico-chemical characteristics.5) The soil nematode abundance, trophic groups, species richness and nematode ecological indices had corresponding changes with the soil environment. The total numbers of nematode in gangue district were least, only26.5individuals per100gram dry soil. And the growth and reproduction of soil nematode is significantly inhibited in gangue district. There was a close relationship between soil heavy metal content and soil nematode community. Zn, Cr, Cu and Pb had more obvious impact on the abundance and diversity of nematode.6) Soil nematode PPI/MI can be used to evaluate soil nutrient condition and reflect the degree of recovery in soil ecosystems. H’、J、λ and MI can well reflect the changes of soil environment between uncultivated vegetation and cultivated vegetations, and they may be used as sensitive index of nematode community under different land-use as well. H’and MI were closely related with soil pollution; therefore can be used as sensitive bioindicator for monitoring pollution.In summary, the variation of habitat in vegetations, quality of soil and degree of soil pollution can be reflected by trophic groups, ecological diversity and ecological indexes of soil nematode, which suggestted soil nematode can be used as effective bioindicator for monitoring soil condition in a certain spatial and temporal scales.