| The mid-1980s, there were a large number of cypress cultivated in the hilly area, because of the large initial planting density, single forest structure, coupled with the lack of scientific forest management, the cypress of ecological functions had gradual degradation, forest productivity deteriorating gradually, had became the low-benefit forest, restrict the development of regional forestry economic. Therefore, it is necessary to carry out the transformation. Soil fauna as indicators of soil quality have a positive response in soil environmental changes. By introducing forest-grass patterns of Juglans regia forest and pasture, transforming the forest of cypress, soil fauna communities and soil nutrient for the study, of different forest-grass transformation patterns on it. Setting Juglans regia+ Cichorium intybus (pattern 1), Juglans regia+Medicago sativa (pattern 2), Juglans regia +Dactylis glomerata (Mode 3) and Juglans woodland (pattern 4), there were compared with cypress forest (BM). Investigation of soil fauna community during two years, the results showed that:The number of total of soil fauna is 2569, there are belonging to four classes 9,21 orders. Nematoda, Hymenoptera, Acarina and Coleoptera (Larvae) as the dominant groups, accounting for 66.02% of the total number of individuals. The common groups were Oligochaetaopisthopora, Araneae, Collembola, Coleoptera, Protura, Diplopoda, Dermaptera, Orthoptera, Geophilomorpha, Lepidoptera (Larvae) and lsopoda, accounting for 30.67% of the total number of individuals; the remaining six species of rare group, accounting for 3.31%.The individual number of soil fauna in four kinds of transformation patterns was significantly (P<0.05) higher than the cypress forest's. During two years, the same individual number of soil fauna in the same forest-grass pattern increased significantly (P <0.05), however, the Juglans regia pattern was not (P>0.05). The seasonal dynamics distribution of soil fauna having a slight similarity in four kinds of transformation patterns, soil fauna activity was weak in winter and spring of the first year, soil fauna individual rare, that was increasing in summer and autumn, In the second year of the transformational period, individual of soil fauna rare only in winter, rest of the seasons were widely distributed,In addition to the December and March in first year, the three kinds of forest-grass patterns density distribution of soil fauna presents " Gathered at the surface " in each month, it decreases from top to bottom, Focused on the top and middle layer in first December, it concentrated in the lower layer in March, the soil fauna density of pattern 4 and BM in the March and June were concentrated in the top, in December and September, it were concentrated in the lower middle layer.Dominance index in pattern 1, pattern 2 and pattern 3 were decreased in the last two year, both increased in pattern 4 and BM, the diversity index and evenness index increased in pattern 2 and pattern 3, decline in pattern 1, pattern 4 and BM, the density-group index in pattern 1, pattern 2 and pattern 3 in both rising and falling in pattern 4 and BM, pattern 3 diversity index, evenness index and density-group index up growth was fastest, pattern 4 density-group index fell the fastest, BM is the largest decline in the diversity index and evenness index.Four kinds of transformation patterns was significantly (P<0.05) increase soil phosphorus and potassium content, although compared to the cypress forest, the effect of soil organic matter and nitrogen content in three forest-grass transformation patterns was not obvious (P>0.05), but during the two-year renovation, the soil organic matter and nitrogen content has an increasing trend.Correlation between the characteristics of soil fauna and soil physical and chemical properties:soil fauna individual number was extremely significantly (P<0.01) positive correlation with density-group index, and was extremely significantly (P<0.01) negative correlation with pH, pH also was extremely significantly (P<0.01) negative correlation with the density-group index. Total nitrogen was extremely significantly (P<0.01) positive correlation with organic and nitrogen, total potassium was extremely significantly (P<0.01) positive correlation with phosphorus, and was significantly (P<0.05) positive correlation with total phosphorus and potassium, total phosphorus was extremely significant (P<0.01) positive correlation with phosphorus, and Organic was extremely significant (P<0.01) positive correlation with nitrogen, both of them were significantly (P<0.05) positive correlation with the diversity index.In summary, studying the characteristics of soil fauna and soil physical and chemical properties, forest-grass patterns can effectively increase the individual density of soil fauna, soil rich animal diversity, it improve soil physical and chemical properties, improvement is not obvious difference among three kinds of forest-grass patterns, and the Juglans regia+ Cichorium intybus (pattern 1) is the best, its individual number of soil fauna, soil total potassium and potassium content increased significantly. |
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