Relative Efficiency of New Urea Based Nitrogen Fertilizers for Rice Grown in a Light Textured Soil

Sulphur coated urea, lac coated urea and urea briquettes were evaluated relative to prilled urea applied in splits to rice grown in a highly percolating light textured soil. Linear grain yield and N uptake responses were obtained up to 120 kg N/ha. Availability coefficient ratios for different fertilizers were computed following concurrent straight line response model. Sulphur coated urea and lac coated urea were significantly more efficient than split dose of urea. Deep placed urea briquettes which are expected to check denitrification and ammonia volatilization losses, were not found to be an efficient source of nitrogen in the soil under investigation.