Changes of Urease Activities under Greenhouse Soils in Yunnan Province

Choosing the largest one of the six facilities cultural area in Yunnan Province,the urease activities and physical-chemical properties were determined.The trend of urease activities was closely related to nitrogen transformation.The results showed that the soil urease activities in 0-20cm soil layer under greenhouse were 0.093-1.505(mg g,24h.37℃),with the average of 0.474(mg g,24h.37℃),lower than that in open soil.The soil urease activities in 20-40cm soil layer under greenhouse were 0.102-1.279(mg g,24h.37℃),with the average of 0.396(mg g,24h.37℃),higher than that in open soil.The urease activities in the two greenhouse soil layers had a V-shaped change patterns with greenhouse life in fifteen years.Soil urease activities were significant positive correlation with soil pH.