Abstract: The photosynthetic rate， stomata conductance，intercellular CO₂ concentration，yield and some other photosynthetic characteristics were studied under five treatments of winter wheat in dryland．The five treatments are rotary tillage without straw return(CK)，rotary tillage with straw(RS)，no- tillage with straw(NS)，subsoil tillage with straw(SS)，deep plowing tillage with straw(DS)．The result showed that all the photosynthetic characteristics in flag leaf of tillage with straw return was greater than the tillage without straw return，this is due to the different soil moisture condition under tillage with straw return．The photosynthetic characteristics of tillage with straw return showed as SS ＞ NS ＞ DS ＞ RS，tillage with straw return in particularly slowing down the degradation of chlorophyll at later grain filling stage．Tillage with straw return reduced the emergence rate and spike number，emergence rate of SS and NS reduced 21．25% and 16．5% compared with CK treatment．The yield，1000- grain weight and Grains per spike of SS were much higher than the other treatments because of the higher photosynthetic rate．Integrated results of this trial， the SS treatment was recommended in dryland．

Key words: Straw return, Wheat, Photosynthesis, Yield

CLC Number: 

• S512.01