灌水对大麦/玉米带田土壤矿质氮影响的研究

Effect of Irrigation on Mineral Nitrogen Concentration in Soils of Maize/Barley Intercropping

在3个氮水平(0,150,300kg/hm2)和两个灌水量(816,1632m3/hm2)下,对3次灌水前、后甘肃河西走廊灌漠土大麦/玉米带田0～200cm土壤矿质氮含量变化进行了研究。结果表明:在灌水前土壤矿质氮含量在0～60cm土层比较高,灌水后0～60cm土层矿质氮含量明显减少,对土壤硝态氮变化影响较大的是第1次和第2次灌水。在150kg/hm2氮水平下,3次灌水大麦带土壤在低灌水量和高灌水量下矿质氮淋失量分别为136.06,142.93kg/hm2,占氮肥用量的90.70%和95.29%;玉米带为95.28kg/hm2和115.89kg/hm2,占氮肥用量的63.52%和77.26%。在300kg/hm2氮水平下,3次灌水大麦带在低灌水量和高灌水量下矿质氮淋失量分别为264.43,237.72kg/hm2,占氮肥用量的88.14%和79.24%;玉米带为163.06,257.76kg/hm2,占氮肥用量的54.35%和85.92%。3次灌水,玉米带土壤矿质氮淋失量在施氮量150kg/hm2时,以第2次灌水淋失量最大,在施氮量300kg/hm2时以第1次灌水淋失量最大;而大麦带都以第1次灌水淋失量最大。说明土壤中矿质氮的淋失首先取决于施氮量,其次才是灌水量。

Before and after each irrigation, the mineral nitrogen concentration in 0~200 cm soil of maize/barley intercropping was determined in Hexi corridor of Gansu province, this research arranges the 3 level of nitrogen application (0,150,300 kg/hm2), 2 level of irrigation water (816,1 632 m3/hm2). The results showed that soil mineral nitrogen concentration was higher at 0~60 cm depth before irrigation, yet it decreased obviously after irrigation, furthermore, soil mineral nitrogen content was more affected by the first and second irrigation.With 150 kg/hm2 nitrogen application,the mineral nitrogen loss of barley strip were 136.06 kg/hm2 after 816 m3/hm2 water irrigation ,and 142.93 kg/hm2 after 1 632 m3/hm2 water irrigation,which account for 90.70% and 95.29% of nitrogen fertilizer application, yet maize strip were 95.28 kg/hm2 and 115.89 kg/hm2,which account for 63.52% and 77.26% of nitrogen fertilizer application. With 300 kg/hm2 nitrogen application, the mineral nitrogen loss of barley strip were 264.43 kg/hm2 after 816 m3/hm2 water irrigation, and 237.72 kg/hm2 after 1 632 m3/hm2 water irrigation,which account for 88.14% and 79.24% of nitrogen fertilizer application, maize strip were 163.06, 257.76 kg/hm2,which account for 54.35% and 85.92% of nitrogen fertilizer application. Among three irrigation,the mineral nitrogen loss was the highest at the second irrigation with 150 kg/hm2 nitrogen application,and the first irrigation with 300 kg/hm2 nitrogen application, yet the barley strip all were the highest with the first irrigation. It suggested that mineral nitrogen loss was first decided by nitrogen fertilizer rate, then irrigation rate.