Integrated fertilizer prescriptions through targeted yield model and prediction of post-harvest soil test values for Kharif Rice (Oryza sativa)

A field experiment was conducted during 2017-18 on an Aeric Haplaquept soil of West Bengal by adopting the inductive cum targeted yield model, and fertilizer requirements were quantiûed for rice (Oryza sativa) based on soil test and yield target. The basic parameters such as nutrient requirement (NR) and contributions of nutrients from soil (C_s), fertilizer (C_f) and vermicompost (C_vc) were computed from the field experimental data and it was found that the contribution of fertilizer-source to the total NPK uptake in rice was far higher than that obtained from vermicompost and soil available sources. Using pre-sowing soil test values, fertilizer doses and grain yield and/or NPK uptake by the crop as independent variables and post-harvest soil test values as dependent variable, PHSTVs prediction equations were developed. Significant R² values were recorded for prediction equations which showed that these equations could be used for the prediction of post-harvest KMnO₄-N, Olsen-P and NH₄OAc-K.