Abstract: 【Objective】 Strategies and practices are required to increase crop yields and improve water use efficiency (WUE) in arid and semiarid rainfed areas. This study was carried out to determine the effect of different plastic mulching modes on water consumption characteristics, grain yield, and soil water recharge postharvest fallow period for winter wheat in a semiarid rainfed Loess Plateau area of Northwest China.【Method】 This experiment was conducted under arid conditions during wheat growing seasons in 2008-2010 and soil water storage, water consumption amount, grain yield and WUE for winter wheat were analyzed by using four cultivation patterns which were whole field plastic mulching with soil covering on the top of mulch and bunch-seeding (A), whole field plastic mulching without soil cover and bunch-seeding (B), ridges mulched with plastic and row-seeding in the furrow (C), and uncovered and row-seeding (CK), respectively. 【Result】 Results showed that compared to CK, the whole field plastic mulching without soil cover and with bunch-seeding increased winter wheat yield by 64.4%-79.1% and WUE by 22.1%-24.0%, with WUE reached 11.9 to 16.6 kg·hm^-2·mm^-1. The whole field plastic mulching with soil cover on the top of the mulch and bunch-seeding increased winter wheat yield by 43.4%-44.4% and WUE by 8.8%-14.6%, with WUE reached11.0 to 14.8 kg·hm^-2·mm^-1. The ridge-furrow mulching and row-seeding in the furrow increased winter wheat yield by 37.0%-39.3% and WUE by 4.2%-4.4%, with WUE reached 10.0 to 14.2 kg·hm^-2·mm^-1. Plastic film mulching was found to able to increase the soil water storage of 0-200 cm soil profile before the jointing stage, increase water consumption amount from jointing to maturity, and increase the proportion of water consumption after jointing to the total water consumption during the whole growing season. Plastic mulching also improved the use of soil water storage during the whole growth period, enhanced deep soil water usage in arid years, and then enhanced the biomass and grain yield at harvest. Plastic mulching led to a higher soil water consumption over the whole growing season, but the water use efficiency was also increased due to much more increase of grain yield. There was a significant positive correlation between the crop productivity and the soil water consumption during the growth period (r=0.96*). Though the high grain yield of plastic mulching was based on high water consumption, the soil moisture in the 0-200 cm depth with plastic mulching was restored from postharvest to the autumn seeding of the next crop to the level equivalent to the soil moisture in open field. The differences of water consumption among mulching treatments were significantly smaller than those between mulching treatment and open field contrast. By comparison of the three mulching methods, an added feature with the whole field plastic mulching with soil cover on the top of the mulch and bunch-seeding is that the plastic film can be reused for the next crops with simplified cropping operation, helping save film cost, and improving economic benefits, and therefore, it was recommended that is the most appropriate cultivation practice in the experiment. 【Conclusion】 It was concluded that the whole field plastic mulching with soil cover on the top of mulch and bunch-seeding is a highly-efficient cultivation pattern for increasing crop productivity, enhancing water use efficiency, and improving economic benefits for winter wheat in the semiarid rainfed Loess Plateau area of Northwest China.

Key words: plastic film mulching, winter wheat, soil water storage, water consumption amount