Effects Of Soil-coated Ultrathin Plastic-film Mulching On Water Consumption Characteristics And Yield Formation Of Winter Wheat

In order to improve the water production efficiency of winter wheat, to relievethe contradiction between water shortage and high water consumption of winter wheat,and to find out new measures for water-saving wheat production in the area, theeffects of irrigation at different growth stages on dry matter accumulation anddistribution, yield components, water consumption characteristics and water useefficiency of winter wheat under soil-coated ultrathin plastic-film mulched conditionswas conducted with a field experiment. The experiment was conducted in ShenzhouCity, Hebei Province during2011-2012winter wheat growing season, with a winterwheat cultivar Shimai20as materials, and six treatments were included: T1, rainfedwheat without mulch （control）; T2, wheat with triple irrigation at jointing, anthesis,and grain filling stages, each75mm, without mulch （conventional irrigation control）;T3, wheat under soil-coated ultrathin plastic-film mulch with single irrigation of75mm at jointing stage; T4, wheat under soil-coated ultrathin plastic-film mulch withsingle irrigation of75mm at anthesis stage; T5, wheat under soil-coated ultrathinplastic-film mulch with single irrigation of75mm at grain filling stage; T6, rainfedwheat under soil-coated ultrathin plastic-film mulch. The experiment was randomizedblock design with four replications and plot area4m×4m=16m2. The main resultswere summarized as follows:1. The wheat winter with soil-coated ultrathin plastic-film mulch yielded morethan7500kg· hm-2with only284mm water consumption, which was116.4¹57.1mm less than the water consumption of conventional wheat production methods. Andthe water use efficiency of soil-coated ultrathin plastic-film mulched wheat winterreached24.03²6.42kg· mm^-1· hm^-2, which was28.1%⁴0.9%higher than that ofconventional wheat production. The water consumption coefficient of winter wheatwith soil-coated ultrathin plastic-film mulch was176.76¹98.93, which was muchlower than540, the current average transpiration coefficient of wheat reported.2. The grain yield of wheat under soil-coated ultrathin plastic-film mulch with75mm irrigation at anthesis （T4）, was equivalent to that with conventional tripleirrigation （T2）. The post-anthesis dry matter accumulation, and the contribution ofpost-anthesis dry matter accumulation to grain of wheat of the treatment （T4） were all higher than those of other treatments with soil-coated ultrathin plastic-film mulch （T3,T5and T6）, and similar to that of conventional water treatment （T2）. These resultsshowed that, the treatment （T4） was beneficial to dry matter accumulation, especiallythe dry matter accumulation after anthesis. For the rainfed wheat without mulchtreatment （T1）, the amount and percentage of pre-anthesis stored assimilateredistribution from vegetative organs to grain after anthesis were all the largest in alltreatments.3. Flag leaf photosynthetic rate of wheat of all treatments reached maximumvalues during heading-flowering period, then decreased gradually with the growingprocess. The photosynthetic rate of rain-fed wheat without mulch （T1） decreased mostquickly among all the treatments, but the photosynthetic rate of flag leaves of thetreatments with soil-coated ultrathin plastic-film mulch （T3, T4, T5and T6） decreasedslowly, especially that of the treatment with75mm irrigation at anthesis stage （T4）decreased most slowly among these treatments. The flag leaf photosynthetic rate ofT4maintained a high photosynthetic rate after21days after anthesis.4. Comparing with the grain yield of wheat in the conventional water treatment（T2）, the grain yields of wheat in the treatments irrigated once under soil-coatedultrathin plastic-film mulch （T3, T4and T5） were reduced, but there was no obviousdifference between the treatments of irrigation during the jointing and flowering andthe conventional production especially,the grain yield of the treatment irrigated75mm at anthesis with soil-coated ultrathin plastic-film mulch （T4） wasthe highestamong the treatments of membrane covering and irrigating once. The reason was that,the grain number per spike and1000grain weight of T4were all the highest amongall treatments, That means that the T4possess absolute advantage in the combinationof the three yield components.5. According to all the results of the experiment, the photosynthetic rate andphotosynthetic production ability of the treatment irrigated75mm at anthesis stage ofwheat under soil-coated ultrathin plastic-film mulch （T4） was higher than those of alltreatments excepting that of the conventional water treatment （T2）. The combinationof the three yield components of T4, however, was optimum among all treatments, sothat the grain yield of T4was the highest among all treatments, and there was noobvious difference with that of the conventional water treatment （T2）. Moreover, thewater consumption of T4decreased for118.7mm, the water use efficiency of T4increased for34.47%. So it is a reasonable technology that the wheat was irrigated75mm at anthesis under the conditions of soil-coated ultrathin plastic-film mulch whichcombining the advantages of water-saving, high and stable grain yield of wheat, andhigh water use efficiency.