| In the long-term stationary test,changes of fertilizer utilization ratio of irrigated desert soil in Hexi Corridor oasis were studied by using the subtraction method.The results showed that the utilization ratio in the initial year was not high.In continuous application of chemical fertilizers,the utilization ratio of nitrogen,phosphorus,potassium was 24.0%～28.0%,17.2%～20.9% and 16.7%～22.1% respectively.In combined application of chemical fertilizers and organic fertilizers,the utilization ration of N,K and P was 25.5%～28.1%,10.2%～12.6% and 23.1%～30.0%.After long-term continuous application of chemical fertilizers,the total utilization ratio of N,K and P was 47.9%～63.8%,22.5%～38.8% and 30.6%～54.6%,increasing by 10.7%～39.8%,6.1%～21.6% and 8.5%～37.9% than the initial year.Combined application of chemical fertilizers and organic fertilizers increased the amount of fertilization and reduced the utilization ratio,and the utilization ratio was 40.8%～50.3%,17.0%～19.0% and 32.1%～49.5%,increasing by 14.0%～24.8%,5.5%～6.8% and 9.0%～19.5% than the initial year.It is an effective way for promoting fertilizer utilization ratio to reduce application chemical P fertilizer on the base of organic fertilizer.Furthermore,it is necessary to increase chemical K fertilization for the balance of K content in the soil. |