Effects of the light and temperature on dry land wheat yield under different tillage systems

Experiments with two factors and seven levels were designed to explore the influences of light and temperature variations on wheat yields the test of light and temperature.And then,a model was employed to simulate wheat yields under different light and temperature from 1971 to 2005 year and analyze the effects of light and temperature on wheat yield under 3 tillage systems.The results showed the relationships between wheat yield and the light and temperature were quadratic parabola with decreased type.Meanwhile,the reduction effect of wheat yield of NTS was greater than that of T and NT.If the annual average temperature rise 1 ℃ with constant light,wheat yield decreased under these 3 cultivation and maximum yield reduction rate was 16.2% with average of 7.6%.If the average light increase 1 MJ·m-2 with constant temperature,wheat yield decreased under these 3 cultivation and maximum yield reduction rate was 13.8% with average of 3.9%.NTS yield change was greater than that of T and NT which suggest that the decreasing effect of NTS on yield was greater than the other two tillage system with the rise of light or temperature.