摘要:河北山前平原夏玉米高产区施肥不合理现象普遍存在，农业面源污染严重。研究华北山前平原水肥一体化条件下夏玉米适宜的氮肥运筹，可为该区氮素优化施用技术及提高氮肥利用效率提供依据。本研究以‘郑单958’玉米品种为材料，于2014-2015年2个玉米生长季，在滴灌条件下设置4个施氮水平（N0：不施氮；N1：120 kg·hm-2；N2：240 kg·hm-2；N3：360 kg·hm-2），研究滴灌水肥一体化下施氮量对玉米氮素吸收利用和土壤硝态氮含量的影响。结果表明：N0处理的玉米干物质重及产量较其他处理显著降低，N1、N2和N3处理间无显著差异；N1处理的玉米氮含量和氮累积量较N0处理显著增加，施氮量在N1～N3范围内，不同年份间玉米植株氮含量和氮累积量存在一定差异，总体表现为随施氮量的增加而上升的趋势，但随施氮量的增加，植株氮含量和氮累积量上升幅度逐渐降低。N2处理的氮肥收获指数最高。随施氮量增加，氮肥当季回收利用率、氮肥农学效率、氮肥生产效率和氮肥利用效率显著降低；2014年，在0～100 cm土层范围内，4种施氮处理的土壤硝态氮含量均表现为随土层加深逐渐降低；2015年N2和N3处理的土壤硝态氮在80～100 cm土层达到累积峰，经过2年种植后，年施氮量超过240 kg·hm-2的处理，土壤硝态氮淋洗加剧。利用一元二次方程拟合产量与施氮量之间的关系，明确了玉米最高产量的施氮量为199～209 kg·hm-2，经济施氮量为174～187 kg·hm-2。综合考虑经济效益和生态效益，该条件下夏玉米滴灌水肥一体化的适宜施氮量为174～187 kg·hm-2。
关键词:滴灌水肥一体化/
夏玉米/
施氮量/
氮素吸收利用/
土壤硝态氮
Abstract:Inappropriate management of fertilizers is common in high-yield summer maize cultivation regions in the piedmont plain of Taihang Mountain, Hebei Province. Fertilizers overuse results not only in serious waste, but also in agricultural non-point source pollution. This study focused on appropriate nitrogen application to support high yield of summer maize under water-fertilizer integration condition. Using 'Zhengdan-958' as the test maize cultivar, four nitrogen rates (N0:no fertilizer; N1:120 kg·hm-2; N2:240 kg·hm-2; N3:360 kg·hm-2 of nitrogen) were set up in 2014-2015 summer maize cultivation seasons under drip fertigation condition. The effects of different nitrogen application rates on the uptake and utilization of nitrogen in summer maize and on nitrate nitrogen content in soil were determined. The results showed that while dry matter weight and yield of maize under N0 treatment significantly decreased, there were no significant differences among N1, N2 and N3 treatments. Nitrogen content and accumulation in maize under N1 treatment significantly increased compared with that under N0 treatment. In the range of N1-N3, nitrogen content and accumulation differed among different years, which increased with increasing nitrogen application rate. However, nitrogen accumulation rate decreased gradually with increasing in nitrogen application rate. Nitrogen harvest index was the highest under N2 treatment among all treatments. Nitrogen recovery efficiency, nitrogen agronomic efficiency, nitrogen productive efficiency and nitrogen use efficiency decreased significantly with increasing nitrogen application rate. In 2014, nitrate nitrogen content under all nitrogen treatments decreased gradually in the 0-100 cm soil layer. In 2015, nitrate nitrogen content in N2 and N3 treatments reached cumulative peak in the 80-100 cm soil layers. This was related to increasing nitrate nitrogen leaching in the soil, which reach down to the 100 cm soil layer when nitrogen rate exceeded 240 kg·hm-2 during the two years of maize cultivation. Based on the relation between N application rate and yield fitted by one variable quadratic equation, the highest maize yield needed nitrogen application rate in the range of 199-209 kg·hm-2 and economic nitrogen application rate in the range of 174-187 kg·hm-2. Considering the ecological environment and economic benefits, the economic nitrogen application rate was the optimal mode for summer maize under drip irrigation condition.
Key words:Drip fertigation/
Summer maize/
Nitrogen application rate/
Nitrogen uptake/
Soil nitrate nitrogen
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