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Excessive fertilization combined with unreasonable irrigation in farmland of the Hetao Irrigation Area (HIR),China,has resulted in a large amount of nitrogen (N) losses and agricultural non-point source pollution.Application of soil amendments has become one of the important strategies for reducing N losses of farmland.However,there is still no systematic study on the effects of various soil amendments on N losses in the HIR.In this study,three types of soil amendments (biochar,bentonite and polyacrylamide) were applied in a maize-wheat rotation system in the HIR during 2015-2017.Yields of maize and wheat,soil NH3 volatilization,N2O emission and NO3-leaching were determined and soil N balance was estimated.The results showed that applications of biochar,bentonite and polyacrylamide significandy increased yields of maize by 9.2%,14.3% and 13.3%,respectively,and wheat by 9.2%,16.6% and 12.3%,respectively,compared with the control (fertilization alone).Applications of biochar,bentonite and polyacrylamide significantly reduced soil N leaching by 23.1%,35.5% and 27.1%,soil NH3-N volatilization by 34.8%,52.7% and 37.8%,and soil N surplus by 23.9%,37.4% and 30.6%,respectively.Applications of bentonite and polyacrylamide significantly reduced N2O-N emissions from soil by 37.3% and 35.8%,respectively,compared with the control.Compared with appfication of biochar,applications of bentonite and polyacrylamide increased yields of maize and wheat by 5.1% and 3.5%,respectively.Our results suggest that soil amendments (bentonite and polyacrylamide) can play important roles in reducing N losses and increasing yield for the maize-wheat rotation system in the HIR,China.