Effect of nitrogen source and water management on rice yield and nitrogen use efficiency

We conducted two experiments using prilled urea and urea super granule to examine the effects of nitrogen source and water stress on rice yield and nitrogen use efficiency. The experimental treatments were 0, 25, 50, 75 and 100 kg N ha-1 (experiment 1). The water stress treatments were: no fertilizer + continuous standing water, water stress before first urea top dress, water stress before second urea top dress, water stress before third urea top dress, water stress before first, second and third urea top dress and all fertilizers+continuous standing water (experiment 2). The experiment was laid out in a randomized complete block design with four replications. BRRI dhan49 was used as planting material. Urea super granule at 75 kg N ha-1 was enough for rice production in aman season and save 25 kg N ha-1 which was equivalent to 55 kg urea. During application of prilled urea water stress before third top dress performed better than continuous standing water in terms of grain yield and nitrogen use efficiency.