Abstract
The influence of continuous compost (cow dung-rice straw) application on the activities of protease, β-acetylglucosaminidase, and adenosine deaminase in soils of upland fields, changes in their activities during the incubation of soils, and relationships between the enzyme activities and the amounts of nitrogen mineralized during the incubation were investigated. The results obtained are as follows : 1) The activities of protease, β-acetylglucosaminidase, and adenosine deaminase in soils of upland fields were remarkably increased by continuous compost application. The degree of increase significantly varied with the kinds of enzymes and soils. 2) When the soils without and with compost application were incubated at 30℃ for 7 weeks under the moist conditions, the activities of adenosine deaminase and especially protease decreased to a larger extent in the soils without compost than in the soils decreased or increased, and the degree of increase was evident in the soils with compost. 3) Protease activity was highly correlated with the amounts of nitrogen mineralized during the incubation of soils (r=0.793, significance at 2% level). A high correlation was also found between the activity of β-acetylglucosaminidase and the amount of nitrogen mineralized (r=0.708, significance at 5% level). However, such a relationship was not found for adenosine deaminase.
