Background: The importance of potassium management in low-fertile soils in heavy rainfall areas, with respect to rice crop productivity, is crucial for developing sustainable rice cultivation in the west coast of southern India. As nitrogen remains heavily subsidized, there is a continued imbalance in the use of nitrogen, phosphorus, and potassium fertilizers. The removal of potassium by the rice crop exceeds its addition through fertilizers and recycling. Most of the soils in the west coast of southern India are low to medium in plant-available potassium. Therefore, the response of rice crops to applied potassium is generally found to be significant in improving yield quality.
Methods: Field experiments were conducted through frontline demonstrations (FLDs) for three consecutive years during the kharif season from 2020-21 to 2023-24 at ten farmers' fields in the Dakshina Kannada district to validate the impact of FLDs on potassium management in coastal rice crops. The fields were randomly selected in Mangaluru, Puttur, and Belthangady taluks. The farmers' practices were maintained as the local check. Observations such as yield, quality parameters, and economics were recorded using the minimum support price of the crop in the respective years for both demo and check plots.
Results: The average grain yield in demo plots was 73.1 q/ha, while it was 53.7 q/ha under farmers' practices. The increase in yield in demo plots may be attributed to the split application of potassium to ensure its availability throughout the crop growth period, resulting in an increase in average growth parameters such as the number of tillers per square meter (623.1) compared to farmers' practices (468.7). On average, demo plots achieved higher net returns (Rs. 1, 54,719) and a B: C ratio of 3.90, compared to farmers' practices (Rs. 1, 05, 414 and B:C 3.05). The higher grain yield in demo plots compared to farmers' practices was reported by Gautam et al. (2014).
