Comparison of STCR and Conventional Fertilizer Approaches for Improved Yield, Uptake and Nutrient Use Efficiency in Greengram

The present study investigates the effects of various fertilizer recommendation approaches on yield, nutrient uptake and nutrient use efficiency in greengram (BGS-9), conducted at ZARS, GKVK, Bengaluru during summer-2024. Soil test crop response (STCR) based fertilizer prescription equations were developed during kharif-2022 by following the methodology of Ramamoorthy et al., (1967) and were validated alongside post-harvest soil test value prediction equations. Results indicated that significantly higher seed yield (17.99 q ha⁻¹) was recorded in the STCR approach for the target yield of 15 q ha-1, where nutrients were applied through integrated approach based on actual soil test values (T3). The highest haulm yield (30.25 q ha⁻¹) was recorded in T2, which followed the STCR inorganic approach targeting 15 q ha⁻¹, based on predicted soil test values. Nutrient uptake results indicated that significantly higher nitrogen (110.73 kg ha⁻¹), phosphorus (11.39 kg ha⁻¹) and potassium (140.06 kg ha⁻¹) uptake were recorded in STCR treatments, particularly in those with an integrated approach. These treatments also validated better nutrient recovery and agronomic use efficiency compared to low, medium and high (LMH) and package of practice (POP) approaches. The findings confirm the accuracy of predicted soil test values in fertilizer prescription, indicating that repeated soil testing between crops may be unnecessary. The STCR based integrated approach provided balanced nutrient application, leading to optimal yield and nutrient uptake. This study highlights the effectiveness of STCR methodologies for efficient nutrient management and improved productivity in greengram.