Soil Test and Yield Target Based Balanced Fertilizer Prescription Model for Green Gram on Alfisols of Tamil Nadu

Background: Green gram, also known as “mungbean” is rich in protein and vitamins. Either chemical fertilizers or organic manures alone may not suffice to meet the nutrient demand with sustenance of soil health. Hence, soil test based fertilizer prescription for green gram becomes need of the hour. Methods: Fertilizer prescription equations (FPEs) were developed for green gram grown under Integrated Plant Nutrition System (IPNS) on Typic Rhodustalf (Palaviduthi soil series) in Tamil Nadu. The developed FPEs were validated through four field experiments with Green gram variety CO 8 conducted during 2023 and 2024 in Dindigul district in the farmers holdings with ten treatments viz., Blanket (RDF alone), Blanket+FYM (RDF + FYM @ 12.5 t ha-1), STCR-NPK alone and STCR - IPNS for 8, 10 and 12 q ha-1, Farmer’s Practice and Absolute control in non replicated manner. Growth, yield parameters and grain yield were recorded and soil fertility was assessed. Result: The highest growth and yield attributes were observed in the treatment receiving STCR-IPNS-12 q ha-1 with an increase of 34.1 per cent over blanket recommendation and 58.08 per cent over Farmers Practice. The post-harvest soil available NPK indicated the build up and maintenance of soil fertility due to soil test based fertilizer recommendation under IPNS. Results highlighted that in all the four locations, the per cent achievement of the targeted yield was within ± 10 per cent deviation from the yield target proving the validity of the STCR-IPNS equations developed for recommending fertilizer doses for green gram.