Activities of soil enzymes in fields continuously cultivated with cassava,sugarcane, and pineapple in middle terrace areas of Lampung Province, South Sumatra, Indonesia

Changes in the activities of soil enzymes (acid and alkaline phosphatases, beta-glucosidase, and arylsulfatase) associated with continuous cultivation of cassava, sugarcane, and pineapple were studied in middle terrace areas of Lampung Province, South Sumatra, Indonesia. Soil samples were collected from fields continuously cultivated with cassava for the period ranging fro m 0 to 10 y, with sugarcane from 0 to 20 y, and with pineapple from 0 to 10 y. Continuous cultivation did not show conspicuous effects on soil pH, and contents of total N, organic C, and available P as well as soil enzymatic activities. However, the changes in the activities of the soil enzymes gene rally showed a significant relationship with the contents of soil organic C and total N.