Soil Test Crop Response Based Fertilizer Recommendations under Integrated Plant Nutrient Supply for Bt Cotton inInceptisols of Haryana

摘要

Field experiments were conducted on Bt cotton to investigate soil test crop response under integrated plant nutrient system (STCR-IPNS) by following Ramamoorthy's inductive approach of fertility gradients in Inceptisols at Research Farm, Department ofSoil Science, CCS Haryana Agricultural University, Hisar during 2011-12 and 2012-13. The experiments were carried out on well developed fertility gradients w.r.t. available N, P and K in the preceding season before sowing of Bt cotton having wide variability of N (105 to 175 kg ha1), P (10 to 32 kg ha1) and K (208 to 392 kg ha1). The nutrient requirement (NR), contribution of nutrients from soil (CS), fertilizer (CF) and farmyard manure (CFYM) were computed using the data on soil test values, fertilizer nutrients doses, uptake of nutrients and seed cotton yield obtained from the main fertility experiments for both the years. The nutrient requirement for producing one quintal of seed cotton was found to be 3.58, 1.20 and 3.50 of N, P_2O_5 and K_2O, respectively. The per cent contribution from soil and fertilizer were found to be 50.65 and 26.00 for N, 55.50 and 26.60 for P_2O_5 and 29.50 and 45.79 for K_2O, respectively. The per cent contribution from FYM was 3.70, 3.32 and 4.35 for N, P_2O_5 and K_2O, respectively. Making use of these parameters, the soil test based fertilizer prescription equations were developed under IPNS for desired yield targets of Bt cotton. The ready reckoner for making fertilizer recommendations for N, P_2O_5 and K_2O nutrients at varying soil test values in Bt cotton was prepared for attaining yield targets of 28, 30 and 32 q ha~(-1).