Evolution of Soil Enzyme Activities of Pinus sytvestris var.mongolica Plantation at Different Ages in Muus Sandland

In order to understand the effects of Pinus sytvestris var.mongolica plantation at different ages on soil enzyme activity,five kinds of soil enzyme(sucrase,urease,phosphatases,catalase,polyphenol oxidase)activities,the relationship between soil enzyme and nutrients and soil enzyme index in Muus Sandland were studied by using the method of time-space mutual substitution.The results showed that sucrase, catalase,phosphatases and urease activities in the soil increased significantly with the increase of stand ages.After 32years,the soil enzyme activities reached the maximum,which were 5.38,2.24,3.07,3.22 times respectively compared to the control.However,polyphenol oxidase decreased by 16%compared to the control after 32years.The significant correlationships were observed between soil enzyme activities and nutrient factors.Therefore the enzymes could be used as good biological indicators in evaluating soil quality.The soil enzyme index could indicate the evolution of soil enzyme activities with the increase of stand ages and could be used as a way to assess soil quality.