15N标记和土柱模拟的夏玉米氮肥利用特性研究

 【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。

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

【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 (P＜0.05) 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.