间作与施氮对秸秆覆盖作物生产力和水分利用效率的影响

2012年3—10月在甘肃省河西走廊石羊河绿洲灌区进行大田试验,研究了不同施氮水平[0、140 kg(N)·hm-2、221 kg(N)·hm-2和300 kg(N)·hm-2]对小麦//玉米间作系统生产力、间作优势和水分吸收利用的影响。研究结果表明:当施氮量达221 kg(N)·hm-2时,小麦单作籽粒产量(5 036 kg·hm-2)和水分利用效率(25.13 kg·hm-2·mm-1)达最大值;当施氮量达300 kg(N)·hm-2时,小麦间作籽粒产量(3 078 kg·hm-2)和水分利用效率(39.76kg·hm-2·mm-1)、玉米单作籽粒产量(9 921 kg·hm-2)和水分利用效率(38.96 kg·hm-2·mm-1)、玉米间作籽粒产量(6 895 kg·hm-2)和水分利用效率(46.31 kg·hm-2·mm-1)达最大值;当施氮量为0 kg(N)·hm-2时,小麦相对于玉米的竞争力(0.049)达最大值;当施氮量为300 kg(N)·hm-2时,小麦//玉米间作的土地当量比(1.33)达最大值;当施氮量为140 kg(N)·hm-2时,小麦相对于玉米的水分竞争比率(0.98)达最大值。与单作相比,小麦//玉米间作具有显著的间作产量优势和水分利用优势。间作方式中小麦的竞争能力大于玉米;小麦、玉米两作物对水分生理需求时间有效性差异是小麦//玉米间作高效利用水分资源的基础,合理施氮能促进间作种植产量优势和水分利用优势的发挥。

Effect of nitrogen application on productivity and water use efficiency of wheat/maize intercropping system under straw mulching

In order to obtain higher grain yields and water use efficiency (WUE), the effects of different nitrogen levels [0 kg(N)·hm^-2, 140 kg(N)·hm^-2, 221 kg(N)·hm^-2 and 300 kg(N)·hm^-2] on the productivity and WUE of wheat/maize intercropping system under straw mulching were studied. A field experiment was conducted in the oasis region of Shiyang River Basin in Gansu Province during the period from March to October 2012. The results showed that grain yield (5 036 kg·hm^-2) and WUE (25.13 kg·hm^-2·mm^-1) reached the maximum at nitrogen application rate of 221 kg(N)·hm^-2 in monoculture wheat. Grain yield (3 078 kg·hm^-2 and WUE (39.76 kg·hm^-2·mm^-1) reached the maximum at nitrogen application rate of 300 kg(N)·hm^-2 in intercropped wheat. Also grain yield (9 921 kg·hm^-2) and WUE (38.96 kg·hm^-2·mm^-1) reached the maximum in monoculture maize, grain yield (6 895 kg·hm^-2) and WUE (46.31 kg·hm^-2·mm^-1) reached the maximum in intercropped maize at nitrogen application rate of 300 kg(N)·hm^-2. Competitive capacity of wheat relative to maize was maximum (0.049) at nitrogen application rate of 0 kg(N)·hm^-2. Land equivalent ratio of wheat/maize intercropping system was maximum (1.33) at nitrogen application rate of 300 kg(N)·hm^-2. Then water competition ratio of wheat relative to maize was maximum (0.98) at nitrogen application rate of 140 kg(N)·hm^-2. The results showed that wheat/maize intercropping system had significant advantage in terms of yield and water use efficiency and wheat competitiveness was greater than that of maize. It was noted that the difference in time of water demand for physiological use by wheat and maize was the driver for the high WUE in wheat/maize intercropping system. Reasonable nitrogen application enhanced the advantages of yield and water use efficiency.