Effect of different border lengths on the irrigation homogeneity and soil nitrat e-N distribution on wheat field

The effect of different border lengths on the irrigation quantity, irrigation homoge neity and soil nitrate-N distribution was studied. The results show that the irrig ation amounts in the longer border (180m) and shorter border (90m) are 132mm and 102mm, respectively. And the spatial variabilities of water and N are enlarged by irrigation in the longer border. Compared to the shorter border, 44mm irrigat ion water and 20kg/hm² N are lost in the longer border. Under conventional irr igation and N fertilization management condition, the spatial variabilities in the water and N do not affect the winter wheat grain yield because of excessive water and N input. Shortening the length of border is the first-line measure if popularizing the optimized production system with N fertilizer and water.