Study on N,P natural supplying capacity and their source absorbed by winter wheat in arid highland under long-term fertilization conditions

The paper studies N,P natural supplying capacity and their source ratio absorbed from soil and fertilizer by winter wheat in Changwu arid highland with 13 years position fertilization experiment of wheat continuous crop system The results showed that N natural supplying capacity was 26.68～27.49 kg/hm2, average 27.2 kg/hm2 and P natural supplying capacity was 5.21～8.49 kg/hm2, average 7.31kg/hm2 Wheat absorbed N from nitrogen fertilizer in 51.9%～76.8%, average 66.6% and the rest from soil Wheat absorbed P from phosphate in 13.6%～47.8%, average 28.7% and the rest from soil On the same fertilizer base, wheat absorbed N,P ratio from fertilizer increased with N,P supplying rates N use efficiency was 32.6%～66.0%, average 51.1%, and P use efficiency was 1.72%～14.02%, average 7.0% under the experiment conditions