Effects of nitrogen nutrition on the physiological characteristics of wheat colony in dryland

The coordinate effects on wheat structural parameter，leaf photosynthetic characteristics，yield and water use efficiency at different nitrogen 1evels in dry 1and farming were studied．The results show that the structura1 parameter．amount of tillers，leaf photosynthetic rate，water use efficiency and yield are increased with nitrogen supplies ，but it is detrimental to the improvement of the colony structure and function when the nitrogen supply exceeds the suitable quantity．So there is a significant coupling relationship between soil water and fertilizer．The production increase depends on not only the fertilizer itself．but also the interaction between soi1 water and fertilizer．