Soil Test Crop Response Based Fertilizer Prescriptions for Achieving Target Yields of Linseed in Varanasi, India

Soil Test Crop Response (STCR) study was conducted at farmer’s field of Varanasi during 2017-2018 by following the inductive cum target yield model to get the fertilizer prescription equations for NPK fertilizer recommendation for linseed, with and without farmyard manure (FYM) under integrated plant nutrient management (IPNM) system. It was noticed that 3.68, 1.15 and 3.84 kg of N, P and K, respectively were required for producing one quintal of linseed grain. The percentage contribution of nutrients from soil, FYM were 10.31, 47.00 and 8.82 for N, 52.66, 45.06 and 5.59 for P, and 14.74, 115.18 and 12.27 for K, respectively. Further, Ready reckoner of fertilizer doses at varying soil test values for different targeted yield (15, 18 and 21 q ha-1) were also developed. Adoption of STCR-IPNM system saved up to 15.5% N, 47.1% P2O5 and 27.6% K2O fertilizer, when applied in combination with 10t ha-1 FYM. Multiple linear regression model identified ‘+ - -’ response type for P and K, and quantified their critical soil test values (24.8 kg ha-1 and 279.9 kg ha-1, respectively). Good agreements between measured and predicted post-harvest soil test (N, P and K) values were observed while calibrating the model. Thus, this STCR approach could be adopted for making site-specific NPK recommendations for experimental site or regions with similar soil and agro-climatic conditions to achieve targeted yield of linseed crop.