A FIELD RESEARCH ON THE EFFECT OF WATER FERTILIZER COUPLING IN CHESTNUT SOIL

The effect of field water fertilizer coupling was very significance in chestnut soil in semi arid region with cold and high elevation. Under amounts of water supply 250～450mm, the concerted use of nitrogen and phosphate fertilizer could improve biological characteristics of aerial part, and promote root system development of subsurface part. The treatment of water supply 350mm and N120P90 had the highest density of root weight which was 1.317mg/cm3, and under water supply 250～450mm the density of root weight increased 0.067～0.375mg/cm3 using P45 than that N60. Water was the main factor limited crop productivity in dry year of water supply 150mm. In other years of water supply 250～450mm the deficient nutrition was the main limiting factor. The treatment of water supply 350mm and N120P90 had the highest water use efficiency which was 7.27kg/(mmhm2), N60P90 had the highest nitrogen use efficiency which were 48.18 and 88.17 percent seperately in grain and plant of naked oat, the highest phosphate use efficiency was in N120P45 which were 21.13 and 30.42 percent seperately in grain and plant. So rational water fertilizer coupling could raised effectively the yield and water and fertilizer use efficiency.