寒地水稻实地氮肥管理的研究与应用

 为解决东北寒地水稻施肥中存在的问题，引进了国际水稻研究所的实地养分管理技术。田间小区试验结果表明，寒地水稻叶片的叶绿素值（SPAD值）在穗分化期、抽穗期与叶片含氮量及叶色卡值（LCC值）之间都呈极显著的正相关（P﹤0.01）。 初步确定寒地水稻的SPAD阈值为38～40，LCC阈值为3.5。与农民习惯施肥（FFP）相比，实地氮肥管理（SSNM）氮肥用量减少25%，千粒重增加0.75 g，氮肥利用率显著提高。研究表明，在产量不降低甚至有所增加的前提下，SSNM可以降低氮肥用量，具有在广大寒地稻区推广的前景。

Study on the Site-Specific Nitrogen Management of Rice in Cold Area of Northeastern China

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.