Abstract: To investigate the effects of straw mulch on soil water evaporation,indoor soil column evaporation experiments were carried out. The straw layer of two positions (soil surface and 20 cm below soil surface),4 application amount [0 (CK),6 000,12 000,and 18 000 kg·hm^-2],and 3 straw lengths (1,5 and 10 cm) were evaluated for their effects on soil water evaporation. Results showed that surface application could significantly inhibit water evaporation. The more the straw was applied,the smaller the daily evaporation intensity was. There were significant differences in cumulative evaporation between treatments with different application amount. Straw length did not show a significant effect on daily evaporation intensity. There were significant differences in cumulative evaporation between treatments with different straw lengths when straw was applied at 18 000 kg·hm^-2. The treatments with straw applied at 20 cm below soil surface had higher daily evaporation intensity than surface application treatments and CK at early stage of evaporation,but had lower than the above two treatments at later stage of evaporation. The cumulative evaporation was significantly different between treatments with different application amount when the straw length was 1 cm or 10 cm. And the cumulative evaporation was significantly different between treatments with different straw lengths when application amount was 12 000 or 18 000 kg·hm^-2. Statistical analysis revealed that straw application amount exerted the greatest effect on cumulative evaporation when straw was surface applied,while straw length had a significant effect on cumulative evaporation when straw was applied at 20 cm below soil surface.

Key words: soil evaporation, straw mulch, evaporation intensity, cumulative evaporation, Shihezi, Xinjiang