Effect of urea fertilizer deep placement days after transplanting using brri prilled urea applicator on transplanted boro rice yield

Abstract

Rice is the most important crop in the developing countries of Asia. In the south and south-east Asia, rain-fed and irrigated transplanted rice occupies nearly two-thirds of the rice-growing area and produces more than 80% of the rough rice. In these areas, prilled urea conventionally applied by farmers is very insufficient in the transplanted rice field, where severe losses occur (up to 60% of applied N) via NH3volatilization, denitrification, leaching, and runoff. Considering loss minimization, an experiment was conducted during the Boro season at Bangladesh Agricultural Development Corporation (BADC) in Sylhet to evaluate the performance of BRRI Prilled Urea Applicator (BPUA) at the different periods after transplanting BRRI dhan28. The results reveal that the field performance of the BPUA was suitable on first day after seedling transplanting under sandy clay loam soil compared to the third day after transplanting (DAT). At the 105 DAT, the height of the crop was found to be 104.3, 104.3, and 95.7 cm for urea deep placement by BPUA on first, second, and third day after seedling transplanting respectively. The maximum grain and straw yield was found at 6.8 t ha-1 and 5.2 t ha-1, respectively which varied with the date of applicator operation after seedling transplanting. The benefit-cost ratio was found 1.63 at first DAT, whereas it was lower on the third days after seedling transplanting. Farmer can apply urea fertilizer in the non-oxidized zone by the BPUA after the first and second day of seedling transplanting in the sandy clay loam soil for maximum yield.