Effects of Different Magnesium Fertilizer Levels on Light-response Curves and Yield of Flue-cured Tobacco

In order to study the effects of different magnesium fertilizer levels on light-response curves and yield of flue-cured tobacco, the light response curve of central leaves of tobacco plants in maturity period were studied by using the flue-cured tobacco K326 as the research object. And three light response curve, including rectangle hyperbola model, non-rectangle hyperbola model and hyperbolic correction model, were used to be screened out the optimal model via analyzing degree of approximation in fitted value and measured value, and on the basis of the comparison and analysis the light response curves and the yield difference of flue-cured tobacco under different levels of magnesium fertilizer. The main results showed that hyperbolic correction model can better fitting of flue-cured tobacco in mature light response curves. With the increasing of magnesium fertilizer right amount, photosynthetic characteristic parameters are increased, and the leaf photosynthetic capacity significantly improved, but when magnesium fertilizer excessive time characteristic parameters instead of down. Under different magnesium fertilizer levels, the rectangle hyperbola model was the best light-response curve models. The treatment that rate of fertilizer application of Mg is 150 kg/hm2 can significantly improve the photosynthetic rate and yield of flue-cured tobacco.