麦茬旱种水稻苗期施氮效应的研究

1985～1986年,在田间和盆栽试验条件下,采用~(15)N示踪技术,对麦茬旱种水稻苗期施氮(三叶一心期前)与产量形成的关系及苗期需氮规律进行了探索.结果表明,苗期植株氮主要来源于土壤,追肥氮所占比重只有1/4～1/5.研究还表明,麦茬旱种水稻苗期对氮肥的利用率较低,认为培肥土壤对麦茬旱种水稻幼苗生长很重要.因而,从经济观点分析,在土壤肥力较高的条件下,苗期不宜施氮.

Effect of Seed 1ing-Topdressing Nitrogen on Dry Seeded Rice (Oryza satiya L.) Followed by Winter Wheat

The relationship between topdressing nitrogen at seedling stage (before three leaves and one heart period) of dry seeded rice followed by winter wheat and yield forming, also the law of requiring nitrogen at seedling stage were probed with 15N traced technique under the conditions of both field and pot cultured during 1985-1986. The results indicated that rice seedling utilized native soil-N much more than fertilizer-N, only about 1/4-1/5 of the nitrogen in seedling came from the fertilizer. Therefore, the dry seeded rice was lower at utilizing nitrogen at seedling stage, it is very important to raise soil fertilizer for rice seedling growing under drying condition. From the economical view, in the fertile soil, it is not suggested to topdress fertilizer at seedling stage of dry seeded rice followed by winter wheat.