不同施氮水平对寒地粳稻群体质量及氮肥利用的影响

为了探讨氮肥施用量与寒地粳稻群体生长及氮肥利用的关系,以黑龙江省水稻品种‘龙粳21’和‘垦稻12’为试验材料,研究了不同施氮水平对寒地粳稻群体质量及氮肥利用的影响。结果表明,氮肥对水稻产量有明显的增加作用,但过度增加氮肥,不仅生育期延迟,分蘖成穗率大幅降低,群体质量恶化,也达不到高产水平。齐穗期的干物质重及叶面积指数均与产量呈显著的二次曲线关系,并得出齐穗期最适干物质重：‘龙粳21’齐穗期最适干物质重为（9262.5±20）kg/hm2、‘垦稻12’齐穗期最适干物质重为（8715.8±20）kg/hm2;‘龙粳21’齐穗期适宜LAI为5.2,‘垦稻12’齐穗期适宜LAI为5.04。同时随着施氮量增加,尽管单位面积植株吸收氮肥量在增加,但氮肥的利用率却在下降,尤其过多氮肥下利用率大幅下降,2个品种均以N1处理最高（44.44%,42.9%）。形成100 kg产量需氮量虽然略有不同,但各处理之间均无显著差异。在本试验下N2处理（纯氮135 kg/hm2）的施氮肥量更为合理。

Effects of Different Nitrogen Application Level on Group Quality and Nitrogen Utilization Ratio of Japonica Rice in the Cold Region

In order to exploring correlation of different nitrogen application level and group growth and Nitrogen utilization ratio of japonica rice in the cold region,‘Longjing 21＇and‘Kendao 12＇of Heilongjiang Province were used to study the effects of different nitrogen application level on group quality and nitrogen utilization ratio of japonica rice in the cold region. The results showed that,nitrogen fertilizer could significantly increase rice yield,but under conditions of the excessive nitrogen fertilizer,not only growth period was delayed and effective tiller rate reduced and group quality was deterioration,but also the yield did not reach high levels. Dry matter weight and LAI of full heading stage and yield had a conic relationship. And the best value of dry matter weight：‘Longjing21＇was（9262.5±20） kg/hm2,‘Kendao12＇was（8715.8±20） kg/hm2.The best value of LAI：‘Longjing21＇was 5.2,‘Kendao12＇was 5.04. At the same time,per unit area plants absorbed nitrogen fertilizer increased with the increase of nitrogen fertilizer application,but nitrogen fertilizer utilization ratio decreased,and the highest utilization ratio was N1（44.44%,42.9%）. Nitrogen fertilizer requirement of 100 kg production was slightly different,but the difference between each treatment was not significant. N2（pur N 135 kg/hm2） was more reasonable.