Effects Of Regulated Deficit Irrigation And Nitrogen Nutrition On Growth And Water-Nitrogen Utilization Of Winter Wheat

Based on regulated deficit irrigation, water deficit and reasonable fertilization were combined to study efficient use of water and nitrogen of crops, which is important measures to achieve water-saving, fertilizer-saving and increase water-nitrogen use efficiency of crops and to promote sustainable development of agriculture in arid of northwest of China. In this paper, with Xiaoyan 22 as test material, four nitrogen nutrition levels and eleven water deficit treatment were provide to carry out the pot experiments to study the effect of regulated deficit irrigation and nitrogen nutrition on growth, yield, yield component factors, water consumption, water use efficiency and absorption of nitrogen of winter wheat, and discuss the sensitive period of water deficit and reasonable amount of nitrogen nutrition during wheat growth. The conclusions were as follows:(1)Water deficit at jointing stage, tassel stage and jointing +tassel stages significantly reduce the plant height, leaf area of winter wheat; water deficit at returning green stage, jointing stage, tassel stage, returning green +jointing stages and jointing +tassel stages significantly reduce the formation of shoot dry matter of winter wheat; water deficit at different growth stages promote the formation of root dry matter of winter wheat.(2)Whether water defict at single or two growth stages, root activity of winter wheat decreased significantly. With the increasing of nitrogen, the root activity of winter wheat appeared increased firstly and then decreased, which the highest root activity of winter wheat appeared in N₂ treatment.(3)Water deficit at period of returning green significantly increased the wheat yield and water use efficiency of 4.95% and 7.56%. Water deficit at jointing stage and tassel stage significantly reduced spikelet bearing number and grain number per spike. Moreover,it significantly reduced yield 5.69%, 8.06%, respectively. No significantly yield reduction was found when water deficit was imposed at milky stage, but water consumption was reduced significantly of 5.44%, and the water use efficiency was significantly increased of 8.02%. Water deficit at seedling establishment + jointing stage and jointing + tassel stage, which yield was reduced seriously, so water use efficiency reduced significantly.(4)Water deficit at period of returning green significantly reduced the root and steam+leaf nitrogen; water deficit at jointing stage made a sharp reduction in nitrogen content of root and steam+leaf, root and steam+leaf nitrogen, nitrogen content of grain, grain nitrogen, plant nitrogen and total nitrogen; water deficit at tassel stage significantly reduced nitrogen content of root and steam+leaf, steam+leaf nitrogen, grain nitrogen, plant nitrogen and total nitrogen; water deficit at returning green + jointing stage, jointing + tassel stage and tassel+ milky stage made nitrogen content of root and steam+leaf cut down seriously; water deficit at returning green + jointing stage, returning green + tassel stage and jointing + milky stage significantly reduced nitrogen content of grain; some root nitrogen were increased and the other reduced when the water deficit at two growth stages; water deficit at two growth stages significantly cut down grain nitrogen, plant nitrogen and total nitrogen.(5)With the increasing of nitrogen, nitrogen content of grain, grain nitrogen showed increasing trend, and nitrogen content of root and stem + leaf, root and stem + leaf nitrogen, plant nitrogen and total nitrogen increased firstly and then decreased, which the maximum appeared in N₂ treatment.(6)Mid- nitrogen treatment (N₂) had the highest yield, the higher water use efficiency and the best yield component factors compared to the other nitrogen nutrition treatment. With the increasing of nitrogen, except water deficit at tassel+ milky stages, the dry matter and yield increased at first and then decreased in the other water treatment, in which N₂ treatment had the highest yield; water consumption of various water treatment increased at first and then decreased, showed N1> N₂> N3> N0. Except water deficit at tassel stage that the water use efficiency showed a tendency of increasing in the other water treatment. N₂ treatment get the highest yield, the lower water consumption and ensured a higher water use efficiency. With the amount of nitrogen increased, spikelet bearing number increased at first and then decreased and the maximum appearde in N₂; except water deficit at jointing +tassel that the grain number per spike showed a tendency of increasing in the other water treatment; in addition to water deficit at jointing + milky stages that 1000-grain weight increased firstly and then decreased in the other water treatment, and the maximum appearde in N₂. In a word, N₂ can get the best yield components.