15N标记水稻控释氮肥对提高氮素利用效率的研究

本文应用^15N示踪技术研究了水稻对空控释氮肥和尿素氮吸收利用效率的影响以及氮的去向，结果表明：施肥后11天内，水稻控释氮肥和尿素的NH3挥发损失分别占施入氮量的0.69%和1.81%，NH3的挥发损失在施肥后第5天时达到最大值，此后逐渐降低。水稻控释氮肥和尿素氮的淋溶损失分别占施入氮量的0.95%和1.02%，水稻控释氮肥氮的淋溶损失在水稻整个生长期间均比较平缓，施肥后40天时略有上升，此后又缓慢降低。用氮素平衡帐中的亏缺量和缺量扣除氨的损失量后计为硝化-反硝化损失量的结果表明，水稻控制氮肥氮的硝化-反硝化损失量占施氮量的3.46%，而尿素氮在硝化-反硝化损失量却高达37.75%，肥料氮在土壤中的残留主要集中在0～35cm的土层中，达91.4%-91.5%，残留在35cm以下土层中的氮甚微，水稻控制氮肥残留在土壤中的氮量略高于尿素处理。水稻控释氮肥利用率高达73.8%，比尿素高出34.9%，水稻控释氮肥氮利用率高的原因是因氮从颗粒中缓慢释放、受淋溶、氨挥发、尤其受硝化-反硝化途径损失的氮较少。在施等氮量的条件下，施用水稻控制氮肥的稻谷产量比尿素的增产25.5%，达到p=0.05的显著水平。

Study on 15N Labeled Rice Controlled Release Fertilizer in Increasing Nitrogen Utilization Efficiency

This paper deals with effect of rice controlled release fertilizer and urea on nitrogen efficiency utilized by rice plant and fate of nitrogen by using 15 N trace technique.Results showed that NH 3 volatilization losses of urea and rice controlled release nitrogen fertilizer in 11 days of fertilizer application occurred 1.81% and 0.69% of applied N,respectively. The amount of NH 3 volatilization loss reached a maximum value in the five days of nitrogen application,after this,was decreased gradually. Leaching losses of nitrogen from urea and rice controlled release fertilizer occurred 1.02% and 0.95% of applied N,respectively. The leaching loss of N from rice controlled release fertilizer changed smoothly during the whole growth period of rice plant,and only increased a little until 40 days after fertilizer application,hereafter,was decreased slowly again. Nitrification-denitrification loss of rice controlled release fertilizer was 3.46%,but that of urea was as high as 37.75%. Residual fertilizer nitrogen in soil was remained in the soil layer of 0-35cm depth and reached 91.4%-91.5%. There was trace amount residual nitrogen under the soillayer of 35cm depth. The total residual nitrogen of rice controlled release fertilizer was slightly more than that of urea. Nitrogen recovery of rice controlled release fertilizer treatment was 73.8% and was higher 34.9% than that of urea. The high N recovery of rice controlled release nitrogen fertilizer may be explained by more following reasons:(1)nitrogen release in its granulated fertilizer was controlled;(2) there was lower leaching nitrogen and lower NH 3 volatilization,especially smaller nitrification-denitrification loss. In condition of equal amount of nitrogen applied,rice grain yield in controlled release nitrogen fertilizer treatment was increased by 25.5% than in urea treatment and which was the significance level in p= 0.05.