Effects of Nitrogen and Irrigation on Photosynthesis Characteristic of Leaves and Grain Yield of Winter Wheat

A field experiment was conducted to investigate the effects of nitrogen application and irrigation on leaf photosynthesis performance and the grain yield formation in winter wheat on the Loess Plateau,China.The results indicated that both nitrogen application and irrigation improved the leaf Fv/Fm and Pn at different crop growth stages,and also increased the ears,grains per ear and the grain yield.Nitrogen applying significantly reduced winter wheat 1 000-grain weight,while appropriate irrigation significantly increased 1000-grain weight.