氮肥运筹对黑龙江省第三积温带水稻抗倒伏能力的影响

Effects of Nitrogen Management on Rice Lodging Resistance of the Third Accumulative Temperature Belt in Heilongjiang Province

为了明确氮肥施用方式对黑龙江省第三积温带水稻产量和倒伏的影响,选用2个主栽水稻品种,设置3个施氮量和4个基蘖肥与穗粒肥比例处理进行了研究。结果表明,在施氮水平较高(161 kg/hm2)时,后期施氮比例适当增加(基蘖肥与穗粒肥比例为6.5∶3.5),可以提高水稻产量。增产原因主要是穗粒肥施用比例增加能增加穗粒数,从而提高了群体颖花数和群体库容量。施氮量增加使株高变高、弯曲力矩增大,抗折力降低,倒伏指数增大;而后期穗粒肥施用比例增加能使水稻茎秆抗折力增大,倒伏指数减小。减少施氮量或增加后期穗粒肥比例,能使水稻倒2节间及其叶鞘长度减小、节间横切面积增大、节间干物质重增加、茎壁变厚,改善茎秆的物理性状。

In order to clear effects of nitrogen management on rice yield and lodging resistance of the third accumulative temperature belt in Heilongjiang Province. The two main cultivated rice cultivars was used in this study,and the nitrogen was applied as the base,tiller,spike and grain nitrogen application ratio to 10 ∶ 0,8 ∶ 2,6. 5 ∶ 3. 5,5 ∶ 5 at three N levels as 0,115,161 kg / ha. The results showed that when the nitrogen application was up to 161 kg / ha and the base,tiller-spike,grain nitrogen application ratio turned to 6. 5 to 3. 5,rice yield increased. The main reason resulting in higher yield was that increase of the spike-grain nitrogen ratio could increase grain number per panicle,panicles number and sink capacity in the population. Increase of nitrogen application rate made plant height increase,bending moment increase,bending force reduce,and lodging index increase. Decrease of the spike-grain nitrogen ratio at late growth stage made rice stem bending force increase,lodging index decrease. Induce of nitrogen application rate or increase of the spike-grain nitrogen ratio at late growth stage could made 2nd internode and its leaf sheath length decrease,area of cross section enlarge,internode dry weight increase,culms wall thicken. Physicalproperties of rice stem improved.