Abstract: Simulating tree shading experiment show that wheat enter a developing stage will post-pone 2 days along with the shading degree adding to 25% ,and soil water (0~40 cm)evaporation will reduce 0.58 per cent point when shading add to 10 % as well. And it also demonstrate that suitable shading degree have direct proportion with wheat chlorophyll content, photosynthetic rate and transpiration rate and as well as has inverse ratio with light utilized rate and water consump-tion rate. The suitable shading degree can stimulate wheat leaf area growth and biomass accumula-tion , and the treatment of shading degree 25 % , for example, is only lower 1.25 % in wheat output but is higher 7.9%in biomass compared with sunshine treatment. To sum up,suitable tree shad-ing degree, less than 20% ,in tree-crop intercropping system will not led to decrease wheat output seriously if tree root effect is ignored, and the shading value can be the largest shading degree value in tree-crop intercropping system.

Key words: Tree-crop intercropping, Shading, Wheat development, Yield, Simulation

CLC Number: 

• S512.1