Effects Of Water And Nitrogen Supply On Growth And Water And Nitrogen Use Efficiency Of Spring Maize In Northern Xinjiang

In view of the large amount of water and fertilizer input and the low efficiency of water and fertilizer utilization in Xinjiang corn production,in this study,the water and nitrogen two-factor pit test of spring maize was carried out in the water and soil improvement experimental site of the Water Conservancy Department of Binhu Town,Changji City.This study designed 3 irrigation levels(3900,4500,5100 m³·hm^-2)and 4nitrogen application levels(48,324,462,600 kg·hm^-2),a total of 12 treatments,and analyzed the effects of water and nitrogen supply on the growth and development,yield,water consumption,quality and water and nitrogen absorption and utilization of spring maize in northern Xinjiang under the condition of drip irrigation under plastic film,and proposes a suitable combination of water and nitrogen supply that is beneficial to the yield improvement,quality improvement and efficient utilization of water and nitrogen of spring maize in northern Xinjiang.The main findings are as follows:（1）Under the same irrigation conditions,the plant height（grain filling stage）,stem diameter（jointing stage）,above-ground dry matter accumulation（except stem diameter,bract and cob）and grain yield of spring maize all increased first and then decreasing with the increase of nitrogen application rate,and except for grain yield,there was no significant difference between N2 and N4 treatments（P>0.05）;SPAD value of leaves（milk maturity stage）,LAI（tasseling stage）and harvest index（HI）showed an increasing trend,and there was no significant difference between N3 and N4 treatments of HI（P>0.05）.Under the same nitrogen application conditions,plant height（grain filling stage）,stem diameter（tasseling stage）,SPAD value of leaves（milk maturity stage）,aboveground dry matter accumulation（except leaves）,HI and grain yield all increased with the amount of irrigation water and increased,and except for HI,there was no significant difference between W2 and W3（P>0.05）;LAI（tasseling period）showed a trend of first increase and then decrease.At the same time,among all treatments,W3N3 had the highest grain yield,reaching 22053.01 kg·hm^-2,an increase of 115.3%compared with W1N1(10241.93 kg·hm^-2).（2）Under the same irrigation conditions,the nitrogen absorption and water use efficiency（WUE）of spring maize increased first and then decreased with the increase of nitrogen application;Nitrogen use efficiency（NUE）,crude protein content and total starch content showed an increasing trend,and the first two showed no significant difference between N2 and N3,and N2 and N4 respectively（P>0.05）.Crude fat content showed an insignificant decreasing trend,while water consumption did not change significantly.Under the same nitrogen application conditions,water consumption and total starch content all increased with the increase of irrigation amount;NUE,Nitrogen absorption and WUE showed a trend of first increase and then decrease,and there was no significant difference between W2 and W3（P>0.05）;Crude protein content and crude fat content showed a decreasing trend.At the same time,among all treatments,W2N3 had the highest WUE(3.86 kg·m^-3);W3N4 had the highest NUE(59.58 kg·kg^-1);W3N3 had the highest total starch content(74.38 g·100 g^-1);The protein content was the highest(12.03 g·100g^-1);the crude fat content of W1N1 was the highest(13.34 g·100g^-1).（3）The effects of irrigation and nitrogen application on the growth and development,yield,water consumption,quality and water and nitrogen uptake and utilization of spring maize have interactive effects（except stem diameter,SPAD,total starch content,crude fat content,and NUE and HI）,and the effects of irrigation,nitrogen application and their interaction all reached a significant level（P<0.05）.From the perspective of the influence degree of irrigation and nitrogen application,the indexes of irrigation>nitrogen application were as follows:plant height,stem diameter,SPAD,yield,dry matter accumulation,water consumption,NUE,total starch content and crude fat content;The indexes of nitrogen application>irrigation were as follows:LAI,HI,nitrogen absorption,WUE and crude protein content.（4）The comprehensive evaluation of water and nitrogen combination treatment of spring maize by entropy-grey correlation degree analysis and CRITIC TOPSIS method showed that the treatment W3N3 was the best combination scheme of water and nitrogen supply.Therefore,it is suggested that the suitable irrigation amount for spring maize under film drip irrigation in northern Xinjiang,which is similar to the fertility of the experimental field,is 5100 m³·hm^-2,and the nitrogen application rate is 462 kg·hm^-2;and when the irrigation water resources are limited,the irrigation amount is 4500 m³·hm^-2 can be used.