| It is of great significance to study the effect of N，P and K on the nutrient contents in wheat grain and
yield of winter wheat in the Loess Plateau. So pot trials was carried out in Northwest A&F University to study the effects of N, P and K deficiency on biomass, yield, 3 yield components and mineral element content in grain of winter wheat grown in soils with high, middle and low fertility soils which were collected from Changwu County ，Shaanxi Province. The obtained results showed that N deficiency decresed significantly spike number and grain number per spike，and therefore decreased the biomass and grain yield. Further more，content S, Ca, Fe，Mn, Cu and Zn in wheat grain were also deceased due to N deficiency . Deficiency of phosphorus decresed biomass, tllers and 1000-grain weight as well as. Mg content in grain. Deficiency of potasium showed no significant effects on yield and nutrient content in the grain of winter wheat. Negative effects of N deficiency were the most serious， and then was P，while the last one was K. |