Soil water retention curves in low suction range during the evaporation process were determined by use of tensiometers to study the effects of three straw treating manners (i.e. cut, aminated or mixed with inorganic soil amendment) on saturated soil water content, soil water retention and supply capacities as well as the soil dehydration rate in the early stage of drought process. Results show that incorporation of finely cut straws into soil enhanced saturated soil water content, improving soil water retention and supply capacities, and the finely cut and aminated straws were more effective than the long cut straws. The dehydration rate of the soil in the early stage of drought in low suction range increased when the straws (both finely cut or long cut) were applied in soil, while decreased with the aminated straws or straws mixed with inorganic soil amendment, and more soil available water conserved. The results provide useful information for more efficient straw-incorporation method to improve the soil water retention capacity.