Abstract: Site-specific nutrient management (SSNM) technology was introduced from International Rice Research Institute (IRRI) to solve the problems in fertilizer application on rice in cold area. A plot experiment showed that there were significantly positive correlations (P﹤0.01)between chlorophyll meter values (SPAD values) and N content in leaves, leaf color chart(LCC)values at panicle initiation and heading stages. Therefore 38-40 was considered as the critical SPAD value, and 3.5 was the critical LCC value for N application. Compared with farmers′ fertilization practice (FFP), the site-specific nitrogen management reduced the total N input by 25%, and increased the 1000-grain weight by 0.75 g, and significantly increased fertilizer-N use efficiency. The results suggested that SSNM has a great potential for reducing N input without cutting down the grain yield. SSNM is a valid agricultural approach for applying N fertilizer on rice in cold area of Northeastern China.

Key words: rice, nitrogen, leaf color chart, yield