Four soil samples were collected from Huajiang distract to represent four different types of land management

including in forest

abandoned land

cultivated land and Zanthoxylum bungeanumforest.Soil aggregates were obtained with dry sieving method for soil enzyme activity analysis.The results show that in the forest

the large soil aggregates(>5 mm)had the strongest soil enzyme activity

and the microaggregates(< 0.25mm)had the lowest.The aggregates from the abandoned land showed an opposite trend

and the aggregates the farmland and Zanthoxylum bungeanum forest were the intermediate.The sucrose

amylase

urease

protease

and phosphatase of the aggregates of all the three sizes showed the highest activity in the forest

and the lowest in the cultivated land.The catalase activity of the aggregates from the abandoned land sample was the lowest.The amylase activity of micro-aggregates(<0.25mm)was the highest. The aggregates showed the order of decreasing amylase

protease

acid phosphatase

and catalase activities as:micro-aggergats>2~1mm aggregates>large aggregats.With increase of aggregate size

the enzyme activity decreased.The aggregates also showed the order of decreasing polyphenol oxidase and urease activities as:micro-aggregats>large aggregats>2~1mm aggregates.The enzyme activity of soil micro-aggregates of was the highest.The forest had the least content of micro-aggregate.The results indicate that the soil enzyme activity in the forest was relatively low

resulting a slow release rate of available nutrients.On the contrary

the nutrients in the cultivated land were released quickly.