Studies on Enzyme Activities in Paddy Soil Affeced by Fertilizer and effective Microorganisms (EM) Application

Abstract

Recently, there was an attempt to amend soil by organic fertilizer associated with effective microorganisms (EM) besides chemical fertilizer. But there was no report on effect or EM on soil enzyme activity which is concerned directly to the decomposition of organic matter in soil. Therefore, the studies on enzyme activities, especially β-glucosidase activity was carried out by sampling the composite soils (0-15 cm depth) from paddy fields growing rice R.D.6 with and without the applications of chemical fertilizer (16-20-0) 30 kg/rai, compost 1,500 kg/rai and EM 4 litre/rai, either singly or combined, for 3 years. Then plant available nutrients and β-glucosidase activities of soils were analyzed. The results indicated that the applications of chemical fertilizer, compost and EM either singly or combined, increased plant available nutrients. The maximum β-glucosidase activity (710 nM/g dry wt.-min, 30^oC) was found in the treatment of EM application. It was about 3.4 times higher than that of the control. While those from the treatments of chemical fertilizer either combined with compost or with EM were higher than that of control about 2 and 2.5 times, respectively. Anyhow, plant available nutrients were found higher in the treatment of chemical fertilizer combined with compost than that of a combination of chemical fertilizer and EM due to a utilization of partial nutrients by microorganisms. So the amendment of soil by an application of chemical fertilizer associated with compost is good enough to obtain the sufficiency of natural soil microorganisms' reaction and organic matter decomposition.