Impact of Integrated Nutrient Management on Soil Properties and Yield of Rice and Wheat in a Long-Term Experiment on a Reclaimed Sodic Soil

Abstract

The effect of inorganic fertilizers alone and in combination with organic manures was evaluated for soilorganic carbon (SOC), bulk density, available soil N, P, K and yields of rice and wheat grown on areclaimed sodic soil after twelve years (1994-95 to 2005-06). The SOC increased in plots receivingN120P26K42 plus green manure (GM) and N120P26K42 plus farmyard manure (FYM) by 28 and 23% over theinitial value but decreased by 31 and 24% in unfertilized and N120P26K42 treated plots, respectively. AvailableN was highest in treatments receiving N120P26K42 plus GM or FYM. Available P increased by 76% over itsinitial value of 11.8 kg ha-1 in treatments receiving N120P26K42 plus GM or FYM and by 28% whereN120P26K42 alone were applied. Application of NPK and its combination with GM and FYM increased riceyields significantly. Applying inorganic fertilizers in rice resulted in nearly similar nitrogen use efficiency(NUE) values when compared to their combined application with organic manures. The NUE increases inwheat due to the residual effect of organic manures in addition to the inorganic fertilizers. The rice yielddeclined by 3.3 and 8.9%, whereas the recommended dose of NPK (120-26-42 kg ha-1) with organicmanures (GM or FYM), the rate was decline by 7.7% and 14.3% for GM and 5.3% and 12.6% for FYMduring five year’s average (1999-2003) and two year’s average (2004-2005), respectively in comparison toinitial five year’s average (1994-1998). However, due to the residual effect of GM and FYM on succeedingcrop of wheat with N120P26K42, the rate of yield decline was 5.2% and 6.0% for GM and 3.6% and 1.9% forFYM during the same years.