Evaluation of the Recent Nitrogen Fertilizer Recommendation for Rice Variety Bg 300 in Dry Zone of Sri Lanka through a Modelling Approach

Abstract

In most regions of Sri Lanka, rice is grown with intensive management under both irrigated and rainfed, low-land puddled conditions. Apart from use of high yielding improved rice varieties recommended by the Department of Agriculture, and timely management of pest and diseases; high rates of nitrogen (N), phosphorus and potassium fertilizers are applied to attain high grain yield. Nitrogen is recommended to be applied in three splits i.e. basal dressing at the time of planting and top dressings at tillering and panicle initiation to increase the N-use efficiency. Farmers apply excess amounts of N because of the availability of subsidised N fertilizers. Based on the latest research findings and to improve the efficiency and effectiveness of N application, the Department of Agriculture recently recommended an application of four splits of N without the application of basal dressing. Therefore, in this simulation modelling study yield response of a widely grown Sri Lankan rice variety Bg 300 under two N application recommendations; with and without the addition of basal dressing was analyzed using the simulation model APSIM. Results revealed that yield obtained through the new recommendation was similar to that of the previous recommendation.