^(15)N标记和土柱模拟的夏玉米氮肥利用特性研究

Studies on the Characteristics of Nitrogen Fertilizer Utilization in Summer Maize Based on Techniques of Soil Column and ^(15)N-label

【目的】定量分析夏玉米氮肥利用特性以及肥料氮的去向。【方法】采用15N标记和土柱模拟技术,设置4个施氮水平(0、90、180、270 kgN.hm-2),在人工防雨棚条件下对平水降雨年型进行了模拟研究。【结果】施氮处理均显著提高了玉米的生物量和籽粒产量,植株和籽粒吸氮量也显著增加。氮肥生理利用效率表现为随施氮量增加先升高后降低,但处理间差异不显著。氮肥农学效率与氮肥表观利用率则随施氮量增加而显著降低。夏玉米对15N标记氮肥的回收率为41.2%—47.8%,2 m土体各土层中的15N残留量随施氮量的增多而显著增加(P<0.05),15N残留率为40.7%—47.5%。在空间分布上,土壤中残留15N总体表现为随土壤层次加深而明显下降。15N的损失量随施氮量的增加而显著增加,损失率为9.0%—13.1%。【结论】施氮量90—180 kg.hm-2有利于提高玉米籽粒产量和氮肥利用率,减少土体(尤其是深层土壤)中的肥料氮残留量,从而减轻对生态环境的压力。

【Objective】For quantitatively studying the characteristics of nitrogen（N） fertilizer utilization and the fate of fertilizer N in summer maize,an experiment was conducted in Wuqiao Experimental Station of China Agricultural University in 2005.【Method】The experiment design was employed with four N fertilizer application rates（0,90,180,270 kgN.hm-2） and three replications in each treatment,and was carried out by the techniques of soil column and 15N-label under the condition of artificial weather shed.【Result】Application of N fertilizer significantly improved the dry matter,grain yield,total N uptake rate of maize plant and grain.There was no significant difference in PNUE（physiological N fertilizer use efficiency） but showed a tendency of rising firstly and falling then with the increase of N fertilizer applied.AENF（agronomic efficiency of applied N-fertilizer） and ANRE（apparent N fertilizer recovery efficiency） decreased significantly with the increase of N fertilizer applied.The recovery ratio of 15N was 41.2%-47.8% in maize season and the percentage of residual 15N in 2 m-depth soil body was 40.7%-47.5%.Residual 15N rates of different soil layers increased significantly with the increase of N fertilizer applied（P0.05） and decreased obviously with the add of soil layer depth.Loss rates of 15N increased significantly with the increase of N fertilizer applied and total 15N loss ratio was 9.0%-13.1%.【Conclusion】Proper rates of N applied（90-180 kg.hm-2）would be favorable to improve grain yield and N use efficiency,reduce residual 15N rates in soil body（especially in deep-soil layer） and therefore lighten the environment pressure.