Soil Test based Targeted yield equations for blackgram (Vigna mungo L.) through Integrated Plant Nutrition System on Alfisol

Using Ramamoorthy's inductive methodology for assessing the soil test based crop requirement by adopting an Integrated Plant Nutrition System to create Fertilizer Prescription Equations (FPEs) for blackgram with the prime objective of attaining the targeted yield by the farmers. A field experiment was conducted out on red non-calcareous sandy loam soil belonging to the Palaviduthi soil series (Typic Rhodustalf) during rabi 2021-22. The experiment comprised of eleven treatments viz., STCR - NPK alone and STCR - IPNS for yield targets 1.0,1.2,and 1.4 t ha-1, Blanket (25:50:25) @ 100% with and without FYM (12.5 t ha-1), FYM alone @ 6.25 and 12.5 t ha-1 and absolute control in randomized block design with three replications. From the experimental data, basic parameters viz., nutrient requirement (NR), per cent contribution from soil (Cs), per cent contribution from fertilizers (Cf), and per cent contribution from FYM (Cfym) were computed. The quantity of fertilizers contributed by the application of Farmyard manure was assessed. It has been found that the nutrient requirement for producing one quintal grain of blackgram was 4.77 kg of N, 4.50 kg of P2O5, and 5.05 kg of K2O. The per cent contribution from soil (Cs) was 15.61, 29.91, and 8.12 for N, P, and K respectively and the percent contribution from fertilizers (Cf) and FYM (Cfym) was 48.61 and 37.19 for N, 44.78, and 14.63 for P2O5 and 55.72 and 31.71 for K2O. FPEs for blackgram were generated using these basic parameters through a Soil Test Crop Response based Integrated Plant Nutrition System (STCR-IPNS). Fertilizer Prescription Equations (FPEs) created in this mode were used to create nomograms for a range of soil test values and yield targets. Thus the Inductive cum Targeted Yield Model used to develop fertilizer prescription equations provides a strong basis for soil nutrient maintenance consistent with high productivity and efficient nutrient management in farming for sustainable and enduring agriculture.