Abstract: The effects of straw mulch amount on soil water and temperature were studied in dryland agriculture areas in Shouyang of Shanxi province. The dynamic changes of soil moisture,and temperature conditions beneath mulches of maize straw applied at different amount(1500,3000,4500,6000kg/ha ) and soil transpiration were investigated from April to November in 2009,the whole growth season of spring maize. The results showed that straw mulch had a beneficial effect on soil transpiration and temperature of topsoil lay within 40cm at the early growth stage,while had no significant effect at the later stage after reaching the maximum LAI,the beneficial effect of straw mulch on reducing evaporation and improving soil water retention were increased significantly with the increasing applied amount of straw mulch. On the other hand,we found that there were adverse effects of high application mulch amount on soil moisture by interception loss and suspending infiltration of rainfall,and interception and field infiltration of rainfall under mulch condition were related to climate conditions,rainfall intensity,soil hydraulic characteristic etc.,how the straw mulch amount affect field infiltration and interception of rainfall should be further studied. Similarly,Straw mulch affected topsoil temperature,mulch exceed certain amount could lead to low temperature to affect crop growth and yield. In this study,the recommended amount of straw mulch for the studied areas was 4500kg/ha with taking into consideration of integrated effect on both soil water content and temperature. These findings are important for identifying the best straw mulch practices for dryland agriculture,and would provide useful reference for further studies in this field.

Key words: Straw mulch amount, Straw mulch amount, Dynamic change of soil moisture, Dynamic change of soil temperature