Effect Of Interaction Of Water And Nitrogen On Nitrogen Use Efficiency Of Summer Maize (zea Mays L.)

The experiment was conducted in2010-2012at the Maize Technological InnovationCenter of the north China plain (NCP), located at Shandong Agriculture University (36°09′N,117°09′E,128m above sea level) in Taian. The experiment included two maize cultivars(High N efficiency maize Zhongnong99, Z99and low N efficiency maize Lainong14, L14),two irrigation levels (5250m3ha-1and2625m3ha-1during summer maize growth stages),two fertilizer types (urea and manure), and two N fertilization levels (100and200kg N ha-1),with two replications. We focus systematic on the interaction of water and nitrogen (N) onsummer maize N accumulation and distribution, the physiological features of crop N useefficient (NUE), different N loss in the process of maize growth and maize water useefficiency (WUE), to find N and water cycle in the corn-soil-air system. The main resultswere as follows:1. Effect of interaction of water and N on summer maize yield and dry matteraccumulation.Under different N fertilizer level, maize yield of high N treatments were significanthigher than low N treatments, and yield increased significantly with the increase of Nfertilizer. Under the same N level and different fertilizer type, maize yield of urea treatmentswere significant higher than manure treatments. Under different irrigation, maize yield of highirrigation were significant higher than low irrigation. Under the same treatments and differentvarieties, yield of high N efficiency maize Z99were significant higher than low N efficiencymaize L14. Under interaction of different irrigation and N fertilizer, interaction of highirrigation and high N level significant increased yield of two maize varieties. Dynamics ofmaize dry matter accumulation and N accumulation were basicly the same, and both had thesame trend with yield. It plays an important part in improving summer maize water and Nfertilizer supplying to get a higher yield.2. Effect of interaction of water and N on summer maize NUE.NUE of high N efficiency maize Z99was significantly higher than low N efficiencymaize L14, and increasing nitrogen fertilizer application and irrigation within a certain rangecould improve the NUE of summer maize. The interaction of high irrrigation and high N levelhighly increased maize dry matter and N accumulation, and got a higher yield, whichindicated that interaction of water and N could improve summer maize NUE, vegetation nutrient transporting grain capacity and rates, crop harvest index and maize economic yield.3. Effect of interaction of water and N on summer maize N balance.Fertilization and irrigation could promote the ammonia volatilization of summer maize,and inorganic fertilizer treatments performed significantly higher than organic treatments,which decreased faster and more. With irrigation and N fertilizer applied, NO3--N graduallymoved downward to deeper soil layers, and the interaction of high irrrigation and high N levelhighly improved maize ammonia volatilization N loss.The interaction of high irrrigation andhigh N fertilizer highly increased NO3--N content in soil solution and total leaching watervolume from deep soil layer, thus increased summer maize total N loss, and reduced NUE.Based on our findings, it is possible to reduce NO3--N leaching out of the root zone during thegrowing season by split application of irrigation and fertilizer according to maize growthrequirement, and with the appropriate combination of irrigation and fertilizer management.4. Effect of interaction of water and N on summer maize water balance.WUE of high N efficiency maize Z99was significant higher than low N afficiency maizeL14. WUE of high N level was much higher than low N level treatments. While highirrigation emerged much soil water leaching, thus reduced the water use efficiency. IncreasingN application significantly increased the WUE differences between treatments, and improvesmaize water use efficiency. Applying organic fertilizer could improve soil water retentionperformance to improve maize WUE. The interaction of water and N conld highly affectwater balance of the summer maize whole growth stages.