AGRONOMIC EVALUATION OF NEW UREAFORMS FOR FLOODED RICE

Rice (Oryza sativa L. ) seldom utilizes more than 20 to 40% of the applied urea. Inefficient N utilization is largely attributed to N loss through ammonia (NH//3) volatilization and denitrification. Increased N efficiency can be obtained with a slow-release fertilizer such as ureaform (UF), which is the condensation product of urea and formaldehyde. A recent development in the production process of UF utilizes paraformaldehyde (PEA) addition to urea, which produces a modified urea fertilizer containing unreacted urea and methylane urea polymers. The purpose of this study was to evaluate N uptake and yield response of flooded rice and to determine NH//3 volatilization losses from applications of **1**5N urea, UF, and methylenedi-urea.