Soil Enzyme Activity of the Second-generation Chinese Fir Plantation In Huitong County,Hunan Province

To learn more about the soil quality of the second-generation Chinese fir plantation,this paper conducted a characteristic study,in Huitong County,Hunan Province,of soil enzyme activity and relationship between the activity and other factors of soil fertility.The results show that there are close relations between soil enzyme activity and other factors of soil fertility;that soil enzyme activity in natural recovery forest(Ⅶ plot)is apparently higher than that in the 20-year-old second-generation Chinese fir plantation(Ⅲ plot);that the catalase,phosphates and urease activity in ridge soil is lower than that in hillside soil and the enzyme activity in hillside soil is lower than that in valley soil;that with the age increment of the Chinese fir plantation,the soil enzyme activity shows a reducing tendency;and that the enzyme activity varies with the eco-environment: the activity of all four soil enzymes in 0～30 cm soil layer is totally higher than that in 30～60 cm layer,enzyme activity in summer is bigger than that in other seasons,and activity variation during spring,autumn and winter depends on different enzymes.On the whole,there is a collective action of various soil enzymes upon soil fertility.