Effects of methamidophos on amylase, urease and protease activities in soils from Cameron Highlands

B.S. Ismail, Rajasegaran Munusamy and O. Omar

Abstract

Effects of pesticide, methamidophos on the activities of soil enzymes viz. amylase, urease and protease in sandy loam (site 1), loam soil (site 2) and sandy loam (site 3) from uncultivated sites near vegetable farms as control, and soils from three cultivated farms in Cameron Highlands were evaluated under laboratory conditions for up to 28 days. Methamidophos at 10.0 mg/g caused a marked reduction in amylase activities for the entire period of study, especially in soil from site 1 and site 3 (sandy loam). On day 28, the activity of amylase reduced by 27% and 21% of the control in soil from site 1 and 3. However, in soil from site 2, there is a tendency of recovery after day 7. The protease activity in either soil showed a tendency to increase when the incubation periods were prolonged up to 28 days except in soils taken from the farm. Reduction in activity of urease was observed in site 1 and site 2 when treated with 10 mg/g methamidophos. The urease activities declined in soils taken from the farm near site 2 and site 3

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