Activities of soil enzymes in different land-use systems in middle terrace areas of Lampung province, South Sumatra, Indonesia

Abstract

Changes in the activities of several soil enzymes due to land-use conversion from forests to cultivated lands in the middle terrace areas in Lampung Province, South Sumatra, Indonesia, were monitored. Soil samples were collected from 5 locations in the northern and northeastern regions of Lampung, each comprising several land-use systems (secondary forests, cacao plantations, pineapple plantations, rubber plantations, mixed gardens, cassava fields, corn fields, a rice field, etc.) depending on the distribution of the respective land-use systems at each location. Enzyme assays showed that, with a few exceptions, the activities of acid and alkaline phosphatases, β-glucosidase, and arylsulfatase in the topsoils (0 to 20 cm depth) were higher than, and well correlated with, those in the subsoils (20 to 40 cm depth). Activities of soil enzymes were in general well correlated with the content of total soil nitrogen. No distinct differences in enzymatic activities in soils were observed among the land-use systems. Among the soil enzymes studied, acid phosphatase activity showed a significant relationship only with alkaline phosphatase activity in the topsoils. In contrast, alkaline phosphatase activity showed a significant relation with the other enzymatic activities tested in the topsoils and with arylsulfatase and β-glucosidase activities in the subsoils. Arylsulfatase activity also showed a high correlation with β-glucosidase activity in both topsoils and subsoils.