Abstract: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 0,20,40,60 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.