Optimizing Rice Yield and Nutrient Uptake: Investigating the Interaction Between Nitrogen and Potassium in Wet Season Rice Cultivation

Abstract

Nitrogen (N) and potassium (K) are important yield-contributing nutrients for sustainable rice production. However, there is not much information in Bangladesh on the co-application of N and K and how they interact to affect rice yield and nutrition. Field experiments with the combined application of five K rates (0, 50, 100, 150, and 200 kg ha‒1) and four N rates (0, 50, 75, and 100 kg ha‒1) were conducted to investigate their interaction effect on rice yield, nutrient uptake, and nitrogen use efficiency (NUE). The biomass yield of rice in maximum tillering (MT) and heading stages was significantly (p <0.05) higher in the combination of 75 kg N and 100 kg K ha‒1. Similarly, the co-application of N and K yielded significantly (p <0.05) higher grain and straw in 75 kg N and 100 kg K ha‒1 combination. Likewise, nitrogen, phosphorus, sulfur, and zinc uptake at MT, heading, and maturity stages were higher in the 100 kg N and 100 kg K ha‒1 combination. Potassium uptake increased with the increasing K rates due to luxurious consumption. Higher K uptake was recorded at all growth stages in the 100 kg N and 200 kg K ha‒1 combination, which was statistically similar to that of the combination of 100 kg N and 150 kg K ha‒1. However, higher agronomic efficiency of N was observed in the combination of 50 kg N and 100 kg K ha‒1. These results imply that optimum rice yield and NUE can be achieved in clay loam soils by applying 100 kg K and 75 kg N ha−1.