小麦/蚕豆间作体系中的氮节约效应及产量优势

通过田间小区试验,研究了小麦/蚕豆间作条件下作物的产量优势及不同施氮水平和种植方式中土壤硝酸盐累积。研究表明,间作可以提高作物单位面积复合产量,增产幅度在6%3～3%之间,不施氮处理间作小麦产量比单作增加达84%;间作和施氮对蚕豆产量没有显著影响。不同种植方式下土壤剖面中硝酸盐累积量趋势表现为蚕豆单作>小麦、蚕豆间作>小麦单作。不施氮、施氮量为20、406、0.kg/hm2条件下,种蚕豆的土壤硝酸盐累积量分别比种小麦的土壤增加了25.4、63.5、50.9、93.4.kg/hm2,间作降低了土壤中硝酸盐累积。小麦、蚕豆间作体系中的产量优势主要是种间氮营养生态位发生了分化,蚕豆通过固定空气氮而减少对土壤有效氮的吸收,把土壤中的有效氮节约供给与之相伴的作物小麦利用。

Spared N response and yields advantage of intercropped wheat and fababean

Field experiment was carried out to investigate the yield advantage of intercropped wheat and faba bean, and on nitrate accumulation in soil profile at different N application rates. The results showed that compound yields in intercropping were increased by 6%-33% comparing to sole cropping, and wheat was the advantage part in yield contribution. Without N application, the yield of wheat in intercropping was 84 % higher than that in sole cropping. Neither N application nor cropping pattern had significantly effect on yields of fababean. For nitrate accumulation in soil profile, soil under sole fababean was the highest, followed by that under intercropped wheat and fababean, and soil under sole wheat was the lowest. Nitrate accumulation in soil under sole fababean were increased by 25.4, 63.5, 50.9, and 93.4 kg/ha comparing to that under sole wheat with N application at the rate of O, 20, 40, 60 kg/ha, respectively. Nitrate accumulation was decreased in intercropping compared to that under sole fababean. Yield advantage in intercropping could be attributed to the change of interspecific nutrient niche. In wheat/fababean intercropped system, fababean depend more on biological N fixation, which spared nitrate in soil to meet N demand of followed wheat.