Effects of different pruning intensity on photosynthetic characters, growth and yield of crops in agroforestry
修枝对复合农林系统内作物光合特性及生长的影响

The effects of pruning on winter wheat and summer maize were investigated to demonstrate whether pruning could act as an optimization measure for agroforestry system. Contrasted to no pruning(CK), four different pruning intensity P1(1/6 height of crown cut down),P2(2/6 height of crown cut down),P3(3/6 height of crown cut down) and P4(4/6 height of crown cut down) were applied to poplar in agroforestry and the agronomic characters, yield components and photosynthetic characters, such as net photosynthetic rate (Pn),transpiration (Tr), stomatal conductance(Gs), intercellular CO2 concentration(Ci) and stomatal limitation(Ls) of winter wheat and summer maize were tested. The results showed that net photosynthetic rate and transpiration rate of crops increased after pruning,which was less remarkable in the afternoon than in the morning. The height,ground diameter and aboveground biomass of winter wheat and summer maize both increased remarkably, and that of summer maize was higher than that of winter wheat. The yield of crops also increased substantially after pruning, and that of wheat mainly came from thousand grain weight and the number of grain per spike, but that of maize mainly came from spike number. The increased yield of maize was higher than that of wheat, but the total yield was lower than that of wheat. So winter wheat was more suitable for agroforesty system than summer maize.