Effects of tillage and weed management on the vertical distribution of microclimate and grain yield in a winter wheat field

摘要

This paper presents results of a field study of the influence of tillage and weed on the vertical distribution of microclimate in the upper, middle, and deeper layers of a winter wheat population and grain yield during the 2008-2009 and 2009-2010 winter wheat growing seasons. The results showed that the microclimate of the winter wheat canopy was different among the upper, middle, and deeper .layers. Illumination was higher in the upper layer of the canopy than in the middle and deeper layers; underno-tillage + weed-reserving, a greater difference was found among the 3 layers. In the upper layer, illumination was the highest and lowest under no-tillage + weed-control and conventional tillage + weed-control, respectively. In the upper layer, air temperature was higher under no-tillage + weed-control than under conventional tillage + weed-control. The effects of air temperature in the middle and deeper layers were relatively low with tillage and considerably higher with weeds. Relative humidity wasthe highest and lowest under no-tillage + weed-reserving and conventional tillage + weed-control, respectively. During the winter wheat growing seasons, illumination and air temperature were lower at the heading stage and increased to a maximum at the filling stage, whereas the trend for relative humidity was the opposite. With weed-control, grain yield was significantly (LSD, P < 0.05) higher under conventional tillage than under no-tillage; with weed-reserving, no significant (LSD, P < 0.05) differences in grain yield were found between conventional tillage and no-tillage. The results showed that tillage and weed influenced microclimate vertical distribution in the winter wheat canopy and grain yield of winter wheat.