Study On Soil Microorganism And Soil Enzyme Activity Of Different Vegetation In The Rainy Zone Of West China

The rainy zone of West China is located in the west margin of Sichuan basin. Distinctive natural geographical position and climate result in favorable habitat, so the biological diversity is very huge in this region. This dissertation studied on seven different vegetation communities in the forestry experimental station of Sichuan agricultural university, they are the orchard, Cinnamomum amphora, Cryptomeria fortunei Hooibrenk ex Otto et Dietr, Metasequoia glyptostroboides, the Ropencedrymion, Neosino calamus affinis and farmland, that has been chosen as the controlled site. Systematically studied the oil microorganisms and soil enzyme activity under different vegetation, to provide the reference to choose appropriate vegetation types and improve the soil biological activity in this area, The results show:(1) The number of soil microorganisms under different vegetation communities in the rainy zone of West China is very prominence, among the different vegetation types in the same soil layer is significantly different. the largest number of soil microorganisms is in orchard, the following is Neosino calamus affinis, Cryptomeria fortunei Hooibrenk ex Otto et Dietr is minimal. The relation with the quantity between the mainly microorganisms is that:bacterial>actinomyceto>fungi. The most number of bacterial is in the orchard, the least number is in the Ropencedrymion. Neosino calamus affinis has the most number of fungi and actinomyceto. The number of fungi in the farmland is more than other vegetation communities except in the Neosino calamus affinis. The number of actinomyceto is the largest in the Neosino calamus affinis,the second is in the orchard, Cryptomeria fortunei Hooibrenk ex Otto et Dietr is the last one.The number of soil microbial significant change with the seasons, except the number of fungi in farmland was highest in the summer, the number of bacterial and fungi were highest in autumn, The other three quarters is lower; the number of actinomyceto was highest in summer, the lowest in spring and winter.(2) The activity of urease is highest in the Neosino calamus affinis sites, and the farmland is lowest. The activity of catalase in the Cinnamomum amphora、the Ropencedrymion and farmland sites is higher than the orchard and the Neosino calamus daffiness’s, and the lowest is in the Metasequoia glyptostroboides and the Cryptomeria fortunei Hooibrenk ex Otto et Dietr. But the difference of this relationship under different vegetation communities is not obvious. The activity of sucrase in farmland> in Ropencedrymion、in Neosino calamus affinis and in orchard is highest respectively in spring、summer、autumn and winter, meanwhile, both of the Cryptomeria fortunei Hooibrenk ex Otto et Dietr and Metasequoia glyptostroboides is least, and less than the farmland.(3) Among the seven types of vegetation, the amount of microorganism and the activity of enzyme have evident gradient. They decrease rapidly with increasing soil depth.(4) The correlation analysis between the amount of microorganism and the activity of enzyme shows:the activity of sucrose and the amount of bacterial、actinomyceto has positive correlation, but the minus correlation is between the the activity of sucrose and the amount of fungi. The activity of urease and the amount of microorganism also has positive correlation. The activity of catalase and the amount of fungi has positive correlation, but the minus correlation is between the amount of bacterial and actinomyceto. To analysis the correlation among the amount of microorganism、the activity of enzyme and the soil ecological factors shows that they have close relationship. The variation of soil microorganisms and the activities of enzyme is results in the different variety、quality and quantity of the litter under different vegetation communities. The amount of microorganism、the activity of enzyme, which we think as the most important biological activity of soil, can be used to reflect the process of soil quality.