Effect of seasonal fluctuations on enzymatic activities of acid soil as influenced by green manure and phosphorus in Meghalaya, India

摘要

Soil enzymatic activity is a good indicator of overall microbial phenomenon in soil and can serve as a good indicator of soil condition. However, seasonal changes in soil properties may have an effect on soil enzymatic activity, making an accurate assessment of soil quality difficult. Hence an attempt was made to study the effect of green manure and phosphorus on the soil enzymatic activities as influenced by season in a baby corn (Zea mays L.) based cropping system in acid soils of Meghalaya. The present agronomic trial was carried out in summer and kharif, 2012 with green manure in main plot and 3 levels of phosphorus(P) i.e. 0,30 and 60kg P_2O_5 ha~(-1) in sub plot. Direct effect of green manure increased the dehydrogenase (DHA) and phosphatase (PHA) in soil by 18.95 and 7.25%, respectively in summer. The maximum DHA observed with the direct effect of 60 kg P_2O_5 ha~(-1) was 67.34 ug (TPF) g~(-1) (dw) soil h~(-1) whereas maximum PHA of 53.44 ug pNP g~(-1) (dw) soil h"1 was obtained in phosphorus control plots in summer. PHA declined in kharif over summer. Positive correlation was observed between DHA and baby cob yield and a negative correlation existed between bulk density and DHA (P<0.05). Incorporation of green manure with inorganic phosphorus enhanced the enzymatic activity in soil by ameliorating the acid soil and adding organic fractions to it and thereby influencing the yield.