Grey relationship between cropland soil fauna community and the environment factors in Shaanxi

From Jul. 2001 to Oct. 2002, the composition and community structure of cropland soil fauna on a loess soil were studied using hand picking and Cobb method. Totally, 72 soil samples throughout 6 long-term stationary experiments were collected and 5495 cropland soil fauna specimens, which belonged to 6 Phyla, 11 Classes, 22 Order, were obtained. The relationship between cropland soil fauna community and the environment factors was analyzed by gray relationship based on individual of cropland soil fauna(dominant communities, rare community and total numbers of cropland soil fauna), soil microbe(bacteria, fungal and actinomyces) and soil properties(total nitrogen, organic matter, pH, available phosphorus and water content). The result showed that the correlation between environment factors,which were selected by this paper, show an unvarying regularity. pH and soil water content has the greatest affection on individual of soil fauna. The sequence of the affection on cropland soil fauna by soil environment factors is total nitrogensoil organic mattercontaining waterpHbacteriafungalactinomycesavailable phosphorus. The results of dominance analysis indicated that the organic matter has the greatest affection on cropland soil fauna, followed by soil total nitrogen. The synthesis grey correlation reading of organic matter and total N with soil fauna was 0.6555 and 0.6444, respective. The affection of bacteria on soil fauna is smallest, its synthesis grey correlation reading is 0.5429. The influence of soil factors on soil fauna was greater than that of soil microorganism.