Optimizing Fertilizer Use Through Soil Testing and Yield Modeling for Okra (Abelmoschus esculentus) in Alfisolsof Southern India

In the race to increase production, it is imperative to optimize the use of fertilizers through the soil test crop response (STCR)approach. The study was conducted to determine the sound basis of fertilizer prescription for okra at different soil fertility levels and the biochemical changes in the soil. This experiment was executed in three phases to develop and validate fertilizer prescription equations for okra through a soil test crop response approach at the University of Agricultural Sciences, Bangalore, Karnataka, IndiafromKharif 2020 to 2022. The results of the experiment revealed that 0.450, 0.313, and 0.700 kg of N, P2O5, and K2O respectively, were required for producing one quintal of okra fruit under an NPK alone, whereas 0.445 kg N, 0.352 kg P2O5, and 0.698 kg K2O were required in NPK+FYM. The STCR approach, with or without FYM, at the target yields 250 and 220q ha-1 enhanced the yield over the general recommended dose and soil fertility rating approach and it also exhibited a higher NPK uptake and use efficiency, along with better profitability. Similarly, the biological metrics were considerably higher in STCR-NPK + FYM treatments. The developed STCR equations for the aforesaid crop are valid as the percent deviation of fruit yield from the targeted yield was within ±10%. Fertilizer recommendation through the STCR approach is a promising option for okra crops under varied soil fertility levels as it improves crop productivity, and fertilizer use efficiency and maintains the biological health of the soil.