中文摘要：

利用土壤水分传感器、微型蒸渗仪与涡度相关系统,连续监测覆膜和露地春玉米田土壤水分、蒸发和农田蒸散,分析春玉米田蒸散与土壤蒸发变化规律,探讨了覆膜玉米高产节水增效的机理。结果表明：与露地相比,覆膜的表层土壤温度和体积含水率分别提高4.9%和19.5%。覆膜、露地处理玉米出苗率分别为99.0%和80.0%,其差异为显著水平,覆膜提早春玉米各生育阶段平均为7d,全生育期缩短11d。生育前期、中期,覆膜的叶面积指数、株高和地上、地下干物质均显著高于露地的,播种一个月后差异最大,分别高110.2%、13.5%、42.9%和12.7%。玉米拔节期前（6月前）和8月后至玉米成熟,覆膜的农田蒸散量分别比露地的低6.8%和0.4%,但6-8月覆膜的比露地的高5.1%。全生育期覆膜的农田蒸散量为376.2mm,降低了6.0%,且土壤蒸发降低了57.7%。最终单株平均果穗质量、生物量差异不显著。但是,由于覆膜显著提高了出苗率从而增加了单位面积生物产量和经济产量,增幅分别为23.7%和15.3%。同时,覆膜作物水分利用效率提高了22.6%,达到31.3kg/（hm2·mm）。可见,覆膜能显著降低土壤蒸发和农田总蒸散量;保水增温促出苗,提前玉米各生育期;生育中期日蒸散量和干物质积累速率较高;最终显著提高单位面积生物产量和经济产量以及作物水分利用效率。

英文摘要：

Using soil moisture sensors, micro-lysimeters and eddy covariance systems,dynamics of soil moisture and evaporation, farmland evapotranspiration, and growth of rain-fed spring maize were monitored continuously in plastic mulching and un-mulching fields, and the changing regularities of soil evaporation and farmland evapotranspiration also were analyzed to explore the mechanism of plastic mulching enhancing maize yield and water use efficiency. Results suggested that, in comparison with un-mulching, plastic mulching treatment had seedling emergence rate of 99%, which was significantly higher than 80% of the former, in addition with the help of plastic mulching, each growth stage of spring maize emerged an average of 7 days in advance, meanwhile whole growth period shortened 11 days. The temperature and volumetric water content of plastic mulching soil surface layer increased by 4.9% and 19.5% respectively. Except the late growth stage, the leaf area index （LAI）, plant height, aboveground and underground dry matter of plastic mulching treatment significantly were higher than un-mulching treatment, while a month after sowing by 110.2%, 13.5%, 42.9% and 12.7% respectively. Before jointing stage and from August to mature stage, the evapotranspiration of plastic mulching treatment is lower than non-mulching treatment by 6.8% and 0.4% respectively, and between June and August, the evapotranspiration of plastic mulching treatment is higher than the latter by 5.1%. Finally, the difference of average grain weight and biomass per plant in these two treatments is not significant; however, because plastic mulching improved the emergence rate significantly, the biomass and seed yield per unit area increased by 23.7% and 15.3% respectively. At the same time, the plastic mulching also markedly improved crop water use efficiency by 22.6% to 31.3 kg/（hm 2 ·mm ） . It is thus clear that plastic mulching significantly reduced soil evaporation and evapotranspiration, retained soil water and heat to promote maize germination,