Effects of long-term application of fertilizer on wheat nutrient uptake and soil fertility in Loess Plateau

Based on a 20-years long-term fertilization experiment with fixed site on continuous wheat in Changwu,Shaanxi Province,the effect of long-term fertilizer application on the soil fertility and wheat nutrient uptake was studied.Results showed that rational use of chemical fertilizer not only increased wheat yield,but also increased N,P and K content in wheat to some extent.Single applying chemical fertilizer increased N,P and K uptake in wheat and straw,but the combination of N and P had a more pronounced effect,which increased by 143.3%,186.4% and 171.6% in N,P and K uptake in seeds,respectively.The combination of N,P and manure improved soil N,P and K content,increased nutrient content in grain and improved grain quality.Soil organic matter,total phosphorus,available phosphorus and available potassium were increased,while total N and available N were decreased in single phosphorus treatment.The combined application of N,P and manure made the soil organic matter,total N,total P,available N,available P,available potassium increased by 69.0%,57.5%,54.8%,73.1%,830.5% and 119.1%,respectively.It indicated that applying manure could increase soil fertility.