Growth and nutrient uptake of rice (Oryza sativa L.) as influenced by varied rate of potassium humate foliar application

A field experiment was conducted during the Kharif season of 2021-22 at the Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar, to evaluate the effect of different rates of potassium humate foliar application on rice growth and nutrient uptake. The experiment followed a randomized complete block design (RCBD) with nine treatment combinations and three replications. The findings demonstrated that foliar application of potassium humate @ 3 g L-1 at tillering and panicle initiation (PI) stages (T7) significantly enhanced plant height (121.8 cm), tiller density (437.8 tillers m-2), dry matter accumulation (1079.11 g m-2), LAI (4.41), crop growth rate (18.18 g m-2 day-1), relative growth rate (40.82 mg g-1 day-1), grain yield (5234 kg ha-1) and nutrient uptake compared to other treatments. However, it was statistically at par with T9 (potassium humate @ 4 g L-1 at tillering and PI stage) and T5 (potassium humate @ 2 g L-1 at tillering and PI stage), indicating a saturation effect beyond a certain dosage. This suggests that an optimal dose of potassium humate can enhance crop performance, supporting its potential use as a biostimulant for improving rice productivity under field conditions.