Soil Enzyme Activities And Microbial Diversity Of Five Representative Planted Forests In South Subtropical China

Soil is one of the most important components of earth ecosystem,and the changes of its internal ecosystem structure and function can reflect the difference of the vegetation types.This paper take Pinus massoniana plantation,Castanopsishystrix plantation,Mytilarialaosensis plantation,Micheliamacclurei plantation,four kinds of typical subtropical native plantations,and Eucalyptus plantation which is exotic plantation located in Fubo Experimental Center of Chinese Tropical Forestry Research Institute of forestry science which in the city of Pingxiang a as the research object,we research different forest types' enzyme activity,microbial biomass carbon and nitrogen and functional diversity in different soil layers(0-20,20-40 and 0-60 cm),and we explored the effect of physical and chemical properties and soil microbial biomass to soil enzyme activity;and then comparative analysis of various forest types of soil surface(0-20cm)micro biological genetic diversity.The results are of great significance to the selection of tree species for vegetation restoration and the multi objective management of plantation in the hilly red soil region of South subtropics.(1)The soil enzyme activity in different layer of Pinus massoniana,Castanopsishystrix,Mytilarialaosensis and Micheliamacclurei plantation(urease,protease,alkaline phosphatase,invertase and cellulase)and microbial biomass carbon and nitrogen content were higher than Eucalyptus trend,and with the increase of soil depth significantly decreased(P<0.05).(2)The total carbon content and urease,alkaline phosphatase and invertase activity showed a significant positive correlation(P<0.05);pH had a significantly positive correlation with alkaline phosphatase and invertase activity(P<0.05);the content of available phosphorus and urease activity correlated(P<0.05);microbial biomass carbon nitrogen showed a significant positive correlation with invertase(P<0.05).(3)The time of the highest utilization rate of microbial carbon source was 108 h.The utilization of carbon source by soil microorganisms was significantly affected by time,and decreased with the increase of soil depth.(4)The soil microbial Shannon and Simpson functional diversity index in different layers of Pinus massoniana plantation,Castanopsishystrix plantation,Mytilarialaosensis plantation,Micheliamacclurei plantation were different,but were all higher than that of Eucalyptus plantation.The various of soil microbial functional diversity is caused by sensitive carbon,such as sugar,amino acid,polymer,carboxylic acidsand aromatic carbon source source.(5)There was no significant difference in Shannon genetic diversity index,Simpson genetic diversity index,richness index and evenness of soil bacterial community(P>0.05)in the upper soil layers(0-20 cm)of the four native stand types,but higher than that of Eucalyptus plantations.