Vol. 8, Issue 10 (2019)

Author(s):
D Srinivas and TV Sridhar

Abstract:
The effect long term nutrient management on soil urease activity and grain yield of rice under flooded conditions at Regional Agricultural Research Station, Maruteru, Andhra Pradesh, India was investigated. The five treatments were unfertilized (control), inorganic N fertilizer (90 kg ha^-1), inorganic fertilizer NPK @ 90-60-60 kg ha^{- 1}, FYM @ 10 Mg ha^-1 and inorganic fertilizer NPK @ 90-60-60 kg ha^{- 1}, and FYM@ 5 Mg ha^-1. Among the treatments, significantly higher urease activity was found in NPK fertilizer and FYM followed by FYM, Inorganic NPK, Inorganic N and control. The enzyme activity significantly increased up to panicle initiation stage of the crop growth and there after showed a decreasing trend. Further, NPK fertilizer and FYM recorded significantly higher rice grain yield of 6254 kg ha^-1 followed by FYM (4923 kg ha^-1), inorganic NPK (4217 kg ha^-1), inorganic N (2728 kg ha^-1) and control (2143 kg ha^-1). A twofold of increase in urease activity was recorded at panicle initiation stage of the crop growth and was significantly correlated with TOC content of soils.