Recent Developments in Research on Nitrogen Fertilizers for Rice

摘要

Asian governments and farmers, pressured by growing populations, have sought to increase rice production by using high-yield rice varieties and nitrogen fertilizers. Rice uses nitrogen fertilizers inefficiently, however, especially urea, which accounts for 85% of nitrogen fertilizers produced in Asia. This paper examines studies conducted in 11 Asian countries by the IRRI and the IFDC to determine the causes of nitrogen losses and ways to reduce them. Since these losses cannot be measured directly, a method was devised for measuring them indirectly by measuring losses in the balance of an introduced stable isotope, 15N (15N balance technique). The main nitrogen loss mechanisms were identified as ammonia volatilization and, to a lesser extent, nitrification-denitrification.