Fertilization regulates soil enzymatic activity under long term experiments of rice-rice cropping system

Abstract

Different fertilizers may affect soil enzymatic activity and soil fertility dynamics. These effects were investigated in a long term field experiment with rice-rice cropping system (Oryza sativa L.) at Godavari Alluvials (Vertic chromusters) in Andhra Pradesh. The enzyme activities viz., urease (38.5, 46.2 µg of NH4+-N g-1 soil 2h-1), dehydrogenase (570.1, 596.3 µg of TPF g-1 soil day-1) and acid (85.36, 87.96 µg p-nitrophenol g-1 soil h-1) and alkaline phosphatase (138.7, 144.8 µg p-nitrophenol g-1 soil h-1) were significantly higher in treatment T4 (100 % RD of NPK + FYM @ 5 t ha-1). The enzyme activity of soils, which is governed by microbial population is also significantly higher in INM treatments. Our results demonstrate that soil enzymatic activity acted as a useful indicator of soil fertility dynamics. Enzymatic activities were positively and significantly correlated with content of organic carbon.