Abstract:Hetao Irrigation District (HID) is a main grain production region in China, but it is characterized by less rainfall. Water shortage, soil salinization and excessive application of chemical fertilizers are main important factors that restricting the food and environmental safety in HID. Reasonable and efficient utilization of water and fertilizer resources on saline soil to improve crop production efficiency and reduce nonpoint source pollution of nitrogen are the effective ways to relieve the problem. Referring to the local conventional irrigation (300mm) and nitrogen amount (345kg/hm2) in HID, a field interactive experiment with three irrigation amounts and three nitrogen amounts was carried out in three salinization farmlands (S1, 0.247dS/m; S2, 0.839dS/m; S3, 1.286dS/m) respectively. Three irrigation amounts were 150mm, 225mm and 300mm, which was marked as W1, W2, and W3, respectively, and three nitrogen amounts were 172.5kg/hm2, 258.8kg/hm2 and 345kg/hm2, marking as N1, N2 and N3, respectively. The coupling model of water and nitrogen for maize with border irrigation under three saline soils was established and optimized, and the field experiment combined with model simulation was used to explore the response of maize yield to water and nitrogen regulation in different salinized soils, and provide scientific basis for reasonable irrigation and nitrogen management. Main conclusions were as follows: the maize yields were significantly affected by irrigation in S1, S2 and S3 soils. The yield of maize was increased firstly and then decreased with the increase of irrigation volume in S1, S2 and S3 soils. In addition, maize yields were significantly affected by nitrogen rate in S1, S2 and S3 soils (P<0.05). The yield of S1 and S2 soils was increased firstly and then decreased with the increase of nitrogen rate, but it was decreased gradually as a whole in S3 soils. With the increase of soil salinity, the interactive effect of water and nitrogen on yield was enhanced. Water and nitrogen interaction had insignificant effect on the yield (P>0.05) under S1 soil condition. Compared with W3N3 and W3N2 treatment, the yield of W2N2 was decreased by 441% and 656% (P>0.05), respectively. The maximum yield could be obtained only when the water was better and nitrogen was suitable, but the moderate reduction of irrigation and nitrogen application rate would not significantly reduce the yield in nonsaline land. The interaction effect of water and nitrogen significantly affected the yield of S2 (P<0.05), and the yield of W2N2 was significantly higher than that of the rest of treatments (P<0.05), and suitable water and nitrogen supplying were needed in middle saline soil. The yield was significantly affected by the interaction effect of water and nitrogen (P<001) in S3, and the yield of W2N1 was significantly higher than that of other treatments (P<005), and the higher yield could be obtained when suitable water and less nitrogen were supplied in heavily saline soil. Through the model optimization, the watersaving and nitrogencontrolling management for higher yield of maize in HID were as follows: nonsaline soil (irrigation amount of 25374~28626mm, nitrogen amount of 267.65~318.85kg/hm2), moderately saline soil (irrigation amount of 23325~26817mm, nitrogen amount of 225.22~272.56kg/hm2), heavily saline soil (irrigation amount of 19694~24306mm, nitrogen amount of 179.15~223.35kg/hm2).