A Comparative Study of Fertilizer Recommendations to Optimize Groundnut Yield in Southern Karnataka

A field experiment was conducted during kharif 2022 in Bengaluru rural district, Karnataka, to validate soil test crop response (STCR) based fertilizer prescriptions for groundnut on Alfisols. The study utilized a randomized complete block design with seven treatments, including STCR targets (30 and 25 q ha-1) through inorganic and integrated approaches, General Recommended Dose (GRD), Soil Test Laboratory approach (STL/LMH), and an absolute control. The soil was sandy loam, acidic(pH5.68), with medium available nitrogen and potassium, and high phosphorus. STCR fertilizer prescription equations developed for Zone−5 were used. Results showed significantly higher pod yield with the STCR integrated approach for a 30q ha-1 target (30.19 q ha-1), surpassing other treatments. STCR inorganic approach for 30 q ha-1 and 25 q ha-1 targets yielded 30.02 q ha-1 and 25.17 q ha-1 respectively, while the integrated approach for 25 q ha-1 target yielded 25.94 q ha-1. These were superior to GRD (20.18 q ha-1) and STL / LMH (20.56 qha-1). Nutrient uptake (N, P, K) was significantly higher in STCR-integrated treatments, attributed to improved soil properties and nutrient availability. The STCR integrated approach also demonstrated higher agronomic nitrogen (1.56 kg kg-1) and phosphorus (0.50kg kg-1) use efficiency. The per cent deviation was within ± 10% proving the validity of the developed targeted yield equations. This study concludes that STCR targeted yield equations are highly suitable for groundnut in Zone-5 of Karnataka, promoting higher yields and encouraging the use of farmyard manure for soil sustainability despite initial higher costs.