Abstract: The net photosynthesis rate(Pn),stomatal conductance(Gs),intercellular CO₂ concentration(Ci), transpiration rate(Tr),vapor deficit at the leaf surface(Vpdl)and wheat yield were studied under two nitrogen a-mounts and five straw return amounts treatments,for getting best amount of nitrogen fertilizer and straw return. The result showed that photosynthetic capacity was significantly improved at different quantity of straw returned with ni -trogen,and along with the nitrogen supply increasing,Pn of wheat flag leaf increased. With the increased amount of straw returned,wheat photosynthetic index and yield is to rise after the trend of the drop,higher nitrogen supply can accommodate more straw return amount,6 000 kg/ha straw return amount with nitrogen 150 kg/ha and 9 000 kg/ha straw return amount with nitrogen 225 kg/ha is appropriate coupling quantity to wheat cultivation under this experi-ment conditions.

Key words: Straw return, N supply, Diurnal variation of photosynthesis, Yield

CLC Number: 

• S512.1