Soil Enzyme Activity as Influenced by Seasonal Rainfall and Crop Growth Stages under Long-Term Fertilization and Intensive Cropping with Hybrid Maize

摘要

Soil biological health mediated by enzyme activity is an index for soil fertility and plays a significant role in sustainability of cropping system. A field experiment was conducted in 2013-14 under AICRP-LTFE to study the influence of seasonal rainfall and crop growth stages on soil enzyme activities under long-term fertilization. Ten treatments were imposed as follows: T₁ - 50 % NPK, T₂ - 100% NPK, T₃ - 150% NPK, T₄ - 100% NPK + hand weeding, T₅ -100% NPK + ZnSO4, T₆ -100% NP, T₇ -100% N alone, T₈ -100% NPK + FYM, T₉ -100% NPK (-S) and T₁₀ - Control. The occurrence of monsoon rainfall increased the soil urease and dehydrogenase enzyme activity whereas phosphatase activities recorded lower values. The results also indicated high influence of crop growth stages on enzyme activities which is well evidenced by high phosphatase activity, low urease and dehydrogenase activity at harvest stage of hybrid maize. Among treatments, T₈ - 100% NPK + FYM at 10 t ha-1 recorded highest activities of these enzymes emphasising importance of integrated nutrient management in improving biochemical properties thereby sustaining soil health over long run.