Effects Of Water-Nitrogen Coupling On Oat In North Yin-shan

Effects of water-nitrogen coupling on senescence index, nitrogen metabolism, photosynthetic characteristics, yield and quality are studied for the cultivation and management of oat The experiment was conducted in Wuchuan County of Inner Mongolia in2010to2011.The results showed that:(1) In water stress conditions of W1and W2, a moderate amount of nitrogen could improve the ability osmotic adjustment and drought resistance of oat, result in enhancing Pn、Ci、Gs、Tr and WUE. In the W3conditions, nitrogen application can improved the photosynthetic physiological indexes obviously, W3and suitable N application amount (135kg/hm2) give full play to water and nitrogen interactions advantage, being the best model in this paper referred as the water-nitrogen interaction management model. Applying nitrogen180kg/hm2resulted in negative effect of water-nitrogen coupling. Variance analysis showed that there was significant or very significant interaction between irrigation regime and amounts of N application.(2) The interaction of water and nitrogen on leaf senescence index of oat were restricted by soil moisture. In water stress conditions of W1and W2, a moderate amount of nitrogen could keep higher SOD activity in the whole growth period, prevent the membrane lipid peroxidation effectively, also reduce MDA, soluble protein, chlorophyll content, delay the cell aging and improve the water stress adaptability of oat. While increase nitrogen use, nitrogen fertilizer effect is negative, it could reduce SOD enzyme activity, soluble protein and chlorophyll content, improve MDA content, as a result, speeding up the leaf senescence. In the W3conditions, nitrogen application can improved SOD enzyme activity, Soluble protein, chlorophyll content obviously, reduced MDA, delayed the leaf senescence. When nitrogen use was up to180kg/hm2, nitrogen fertilizer effect is reduced. The influence of water and nitrogen on senescence indexes at different growth periods and yield of oats were in significant or very significant levels, and the interactions between water and nitrogen were very significant.(3) The results showed that there was an obvious interaction between irrigation regime and amounts of N application. Insufficient water conditions of W1、W2, a small amount of N application can improve the adaptability of the drought of oats, and enhance activities of nitrate reductase (NR), glutamine synthetase (GS). W3and suitable N application amount (135kg/hm2) increased activities of N metabolism enzymes, and nitrogen use efficiency, being the best model in this paper referred as the water-nitrogen interaction management model. Applying nitrogen180kg/hm2resulted in negative effect of water-nitrogen coupling. Correlation analysis shows that there existed significantly or highly significantly positive correlations of activities of NR、GS with indices of N uptake and utilization, with different correlation coefficients of different growth stages. Thus,GS activity in function leaves might be a candidate indicator for N uptake and accumulation at different growth stages,and heading stage will be an important period.(4) In the proper water stress conditions of W2, protein, Lys and β-glucan content increased significantly, and oat quality was improved. A moderate amount of nitrogen could improve yield and quality of oats in water stress conditions. Applying nitrogen could increase yield of oat mainly in water enough conditions.oats yield achieved maximum in W3N3conditions.Water, nitrogen to increased production has good to each other. Applying nitrogen too much is not only waste resources, but also reduce the effects of yield improvement.