Development and validation of soil test based fertilizer prescription equations for enhancing yield, uptake and nutrient use efficiency of foxtail millet (Setaria italica) under dryland condition

Balanced crop nutrition will be rewarding to profitable sustainable yield and soil quality.To develop and validate fertilizer prescription equation for foxtail millet under dryland farming situation by encompassing the Soil Test Crop Response approach (STCR), field experiments were conducted at Eastern Dry Zone of Karnataka, University of Agricultural Sciences, Bangalore from Kharif 2017 to 2020 in four phases. Soil test data, grain yield, and NPK uptake by foxtail millet crop were used for achieving four important basic parameters, viz., Nutrient requirement, contribution of nutrients from fertilizers (%CF), soil (%CS), and organic manure (%C-OM) to develop the targeted yield equation and these equations were in comparison with Low-Medium-High (LMH) approach and general recommended dose (GRD). It was found that 4.30, 3.13, and 3.61 kg of N, P2O5, and K2O, respectively were required for producing one quintal of foxtail millet grain under inorganic approach whereas 4.20, 2.87, and 4.19 kg of N, P2O5, and K2O, respectively, under integrated approach. The STCR approach, with or without FYM, at the target yields 13 and 10 q ha−1 enhanced the grain yield over general recommended dose and approach. It also exhibited a higher NPK uptake and use efficiency, along with better profitability. Frontline demonstrations were conducted at Tumakuru district, Karnataka, and grain yield under the STCR approach was increased to the extent of 77.94% compared to farmer's practice. STCR-targeted yield approach could improve the yield, economics, and efficiency of nutrient use for foxtail millet compared to GRD and LMH approach.