Growth, Yield and Nutrient Uptake of Direct Seeded Rice as Affected by Nitrogen and Phosphorus Application

Abstract

Pot and field trials using rice varieties IR 72, MR 84 and MR 142 were conducted to determine the effects of N and P rate on growth, yield, yield components and nutrient uptake of direct seeded rice. The experiments were carried out in a Randomised Complete Block design with four replicates, for the pot trial and three replicates for the field trial. Results from the pot trial indicated that higher N rate increased plant height, tiller number, total dry matter (TDM) and leaf area of direct seeded rice at the different growth stages by 5-8%, 42-43 %, 30-40%, 58-60% respectively. Varietal differences in plant height, tiller number and TDM were related to differences in growth rate and maturation period. Interaction effects of variety x N rate were observed on grain yield and yield components. Higher N increased grain yield of IR 72, MR 142 and MR 84 by 49%, 43% and 26% respectively. Total N, P and K tissue content was increased by 35- 68% with higher N application. At early stages of growth, varietal differences mainly involved P and K content but at heading included N, P and K content. There was however, no significant effect of P rate on all the parameters measured.