| Taking use of experimental data from 2000～2002 and demonstration & popularization information from 2002～2003,the paper analyzed the microclimate feature and its yield-promoting mechanism under straw mulching.The results showed that: straw mulching had dramatic effects on temperature of field's surface layer,air humidity and soil temperature,but wind speed.Straw mulching increased surface sensible heat flux,but decreased latent heat flux and soil heat flux,so the soil evaporation was restricted.As soil surface evaporation was restricted by covering,the ineffective consumption of soil water was decreased,and accumulation was increased accordingly.This was helpful for plant transpiration in later stage,and for water consumption transforming from physical process to physiological process,and from invalid consumption to availability.So straw mulching could increase yield and advance water use efficiency.For winter wheat,straw mulching enabled yield increasing and water use efficiency by 8.08%～10.71% and 3.5%～8.4% respectively,and for summer maize,it promoted yield and water use by 6.08%～11.97% and 7.8%～14.4% respectively. |