A study on the soil microorganisms and enzyme activity of different transformation models of deteriorated Pinus massdoniana forests.

Pinus massoniana is one of the main timber species in the south of the China,there are large areas of the deteriorated P.massoniana forests in the red soil hilly areas due to poor site conditions.The deteriorated P.massoniana forests modified by the broad-leaved tree replanting were selected as the research object and the natural recovery (with human interference) deteriorated P.massoniana forests nearby as the control the soil microbe,enzyme activity and soil physico-chemical properties of different forest types were studied.The results showed that: ①deteriorated P.massoniana forests that had been transformed had a marked increase in the number of soil microorganisms and the number of soil microorganisms in the upper layer were significantly more than those in the lower layers,the number of soil microorganisms in the mixed plantations of Schima superba and P.massoniana was the maximum.②in the 0-20 cm soil layer,of the transformed forests,the activity of woodland soil catalase,polyphenol oxidase,and urease was significantly stronger than that of the control;in the 20-40 cm soil layer,the activity of different enzymes varied in different stand types.③the correlation between the quantity of soil microbe and soil available N,available P,polyphenol oxidase,urease,invertase was significant,through multiple stepwise regression analysis,invertase activity was the first factor affecting the number of soil microorganism.④The content of total phosphorus was the most important factor influencing polyphenol oxidase and catalase activity.Soil available P was the first factor affecting the activity of urease,pH was the key factor impacting soil invertase activity.