Effects of minimum tillage and no-tillage systems on photosynthetic characteristics at late growth stages of winter wheat

The photosynthesis after anthesis is important for wheat yield. In order to investigate the effects of minimum tillage and no-tillage system on photosynthesis of winter wheat, four tillage systems were adopted in Longkou city, Shandong Province, China. The four tillage systems were as follows: conventional tillage with straw turnover (CS), rotary tillage with straw turnover (RS), serrated disk harrow tillage with straw turnover (HS), no-tillage with straw cover (NC). The photosynthetic efficiency after anthesis of winter wheat flag leaf of different soil tillage treatments was investigated through measurements of photosynthetic rate and chlorophyⅡ fluorescence parameters of photosystemⅡ and chlorophyll content. Results show that after anthesis, the net photosynthetic rate (P_n) of CS is higher than that of the two types of minimum tillage of RS and HS, but the senescence of flag leaf of RS and HS are later than that of CS. At the late stage of seed-filling period, two types of minimum tillage especially CS still have a higher level of chlorophyll content, maximal photochemical efficiency of PSⅡin the darkness (F_v/F_m), actual photochemical efficiency of PSⅡ in the light (ФPSⅡ), coefficient of photochemical fluorescence quenching (q_P). So the minimum tillage available of photosynthesis time and the duration of photosynthesis function are longer than CS, which is good for the seed filling. Studies show that RS and HS can be adopted in this region, while NC is not suitable.