Effect of irrigation and nitrogen fertilization on growth and physiological characteristics of summer maize in inner Shiyanghe River areas

The effects of limited irrigation and nitrogen fertilization on the growth and development and physiological characteristics of maize were tested.Take summer maize as the experimental material,water was supplied by four levels: 337.5,675,1 012.5 and 1 350 m3/hm2;and nitrogen also by four levels: 75,150,225,300 kgN/hm2.The result showed that serious water stress restrains maize growth.During maize seedling,sufficient water and high nitrogen make against growth of maize crop.However,mild water stress and moderate nitrogen made an optimum growth state of maize,and water and nitrogen can enhance photosynthesis rate of maize;During maize seedling,water stress is advantage of root growth,under the same nitrogen level,the root shoot ratio(R/S) of different water stress is bigger than that of sufficient water.The leaf water potential increases with the increase of irrigation water amount.Under the same irrigation water amount,with the increase of nitrogen fertilization,leaf water potential of maize during seeding is increased.While under drought condition,the photosynthesis rate is decreased,and increasing of nitrogen can increase the photosynthesis rate.