Study On Community Structure Of Soil Fauna In Eucalyptus Grandis Coppice Plantation

Soil fauna is an important component of the ecosystem and plays an important role in substance cycling, energy flowing, soil forming, soil fertilization. There are many ecological problems about Eucalptrus grandis plantations, which are good for economic benefits, social benefits. The soil fauna community structure, seasonal dynamics, distribution in soil profile and soil properties related with community structure in E. grandis plantation and coppice were investigated here to study the problem of plantation forests management. The results were showed as follows:(1) By preliminary identification, there were 42719 individuals of soil fauna, which belonged to 120 groups,30 orders,14 classes and 7 Phyla in E. grandis plantation. Nematoda, Collembola, Acarina were the dominant groups. The number of Nematoda was great and always determined the changes of soil fauna communities structure.(2) The number of groups and individuals, as well as density of soil animals in soil profile rapidly decreased with the increase of soil depth. The maximum density occurred at litter layer. However the soil fauna moved downward in winter, make the density at 0-5cm layer below ground> litter layer.(3) The number of soil fauna group in E. grandis plantation were highest in summer and lowest in winter; the individual number were highest in winter and lowest in spring. And the seasonal dynamics of soil faunal was similar with Nematoda in individual number.(4) The group number of Collembola and Acarina in E. grandis plantation was not obvious in seasonal variation. The dynamics of individual number was similar in two groups, was highest in summer and lowest in winter. On contrary, A/C value was, higher in spring and lower autumn, which was depend on the number of Collembola.(5) Soil fauna had different seasonal dynamics with different diversity indices in E. grandis plantation. Shannon-wiener and Pielou indices were the highest in summer or autumn and the lowest in winter. In contrast, simpson and DG Indices were the highest in winter and the lowest in summer or autumn. DG index was best in reflecting the ecological characteristics of soil fauna objectively which showed plot A>plot B.(6) The number of the soil fauna and organic matter content was positively correlated, The number of total soil fauna in plot B were significantly related with organic matter content(r=0.955, P<0.05); The number of Nematoda were mostly positively related to water content and pH value, negatively related to siol temperature, The number of Nematoda in plot A were significantly negatively related with siol temperature(r=-0.987, P<0.05); The number of Collembola, Acarina were mostly negatively related to water content and pH value, positively related to siol temperature, The number of Collembola in plot B were significantly negatively related with pH value(r=-0.979, P<0.05).(7) This study shows that, with the development of E. grandis Coppice, the number of soil groups was increasing, the diversity tended to increase(comparison between plot A and plot B).