Abstract: An experiment was conducted to study effect of different plastic film mulching on soil moisture of spring wheat and further to explore approaches of increasing wheat yield and improve water use efficiency. The effect of plastic film mulching with three methods on soil moisture were investigated under semiarid rain fed conditions in the Northwest of China. The results showed that the plastic film mulching could increase the moisture content of soil surface layer (0-20cm) significantly,however,after jointing stage,the moisture content of soil surface layer was obviously lower than the open field treatments. The water consumption of the mulched land was generally less than the control,viewed by the average moisture condition during the whole period of growth of soil body (2m). The moisture conditions of Gansu and Gansu Models among the six were markedly higher than that of open ground. The yield from the land mulched with plastic mulch was higher than that from the open ground,with an average increase of 44.45% and by 711.45kg\hm². The yield from the land mulched in autumn was higher than that from the land mulched in spring. Water assured and the stimulation mechanism of higher yields were the effective use of deep soil moisture and the ability to transport the deep moisture to surface in spring mulching under the more arid soil.

Key words: font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA">Plastic mulching, Spring mulching, Autumn mulching, Soil moisture, Yield