Abstract:Nitrogen, phosphorus and potassium uptake dynamic in terms of interspecific competition and facilitation were studied by comparing intercropped species with corresponding sole species through a 233 field plot experiment and a microplot experiment. The results showed that there was more competitive ability to nitrogen, phosphorus and potassium by wheat than by soybean during more than 80 days of coexistence for spring wheat and spring soybean in the intercropping. Peak of nitrogen and phosphorus uptake by intercropped soybean was delayed to some time after wheat harvesting due to intercropping, which was one of mechanism of intercropping yield advantage. The result of interspecific root partition experiment demonstrated that the border effect of nutrient uptake by wheat was largely due to interaction between wheat root and soybean root.