【作者】 于爱忠；

【导师】 黄高宝； 柴强；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 本研究针对地膜覆盖对农田土壤水热特征研究相对薄弱，围绕作物水分利用效率研究缺乏系统性、对基于经济产量水分利用效率研究多而对阶段水分利用效率研究不足，进而造成农艺节水措施选择上缺乏系统理论依据等问题。选择了水资源问题比较突出的甘肃河西三大内陆河之一的石羊河流域，以大田玉米为研究对象，重点研究了不同覆膜方式和不同灌水处理下，土壤水热特征、玉米产量形成、玉米阶段水分利用效率（基于干物质积累的水分利用效率，WUEET.B）与基于经济产量水分利用效率（WUEET.Y）之间的关系，影响WUEET.B、WUEET.Y的关键因素，得出以下主要结论：（1）西北干旱绿洲灌区，采用全膜覆盖高、中灌水处理或半膜覆盖条件下采用高灌水处理，玉米平均经济产量分别达到13275.5、12880.5和12409.9kg·hm^-2，主要原因是上述三个处理显著提高了玉米穗粒数、粒重和双穗率。相同覆膜条件下，高灌水处理玉米穗粒数、粒重和双穗率较中等灌水处理和低灌水处理均有所提高，其中以全膜覆盖效果最为明显，平均分别达到658.6粒/穗、36.4g/100粒和23.9%。同等灌水处理下，全膜覆盖较半膜覆盖和不覆盖穗粒数、粒重和双穗率和单株叶面积有所提高。（2）供水与地膜覆盖对玉米全生育总耗水量和阶段耗水量影响显著。对于玉米全生育期总耗水量而言，不同覆膜方式下，高灌水处理处理最高，其次是中等灌水处理，低灌水处理最低。同等灌水处理，不同覆膜方式灌水量无显著差异。其中，全膜覆盖条件下，高灌水处理和中等灌水处理全生育期总耗水量较低灌水处理平均分别高25.3%和13.5%；半膜覆盖条件下，高灌水处理和中等灌水处理较低灌水处理平均分别高25.2%和11.7%；不覆膜条件下，高灌水处理和中等灌水处理处理较低灌水处理平均分别高28.4%和14.3%。对于玉米阶段耗水量而言，灌拔节水之前，以不覆膜最高，其次是半膜覆盖，全膜覆盖最低。而在拔节期至成熟期，由于灌水定额的差异，致使相同覆膜方式下，高灌水处理处理玉米耗水量均显著高于低灌水处理处理。（3）适当减少灌水量是提高玉米水分利用效率的有效途径。相同覆膜方式下，减少灌水量有利于提高作物WUEET·B。同等灌水处理下，全膜覆盖WUEET·Y最高，其次是半膜覆盖，不覆膜处理最低。各处理中，全膜覆盖低灌水处理WUEET·Y最高，平均达到19.9kg/hm^-2·mm；半膜覆盖高灌水处理处理WUEET·Y最低，平均仅为13.3kg/hm^-2·mm，较前者低33.2%。WUEET·Y与玉米大喇叭口期至灌浆中期的WUEET·B呈显著的正相关关系。玉米播种至拔节期，大喇叭口期至开花期，这两个生育阶段及玉米全生育期WUEET·B与对应ET、E和E/ET均呈显著的负相关关系。玉米WUEET·Y和ET、E和E/ET呈显著的负相关关系。—（4）在相同覆膜方式下，玉米全生育期Tr对灌水量并不敏感；而在同等灌—水处理下，玉米全生育期Tr对覆膜方式敏感。全膜覆盖条件下，玉米叶片光合速率峰值出现在抽雄吐丝期，而半膜覆盖和不覆膜处理则出现在玉米灌浆中期。—全膜覆盖中等灌水处理An达到最高，平均为47.0mmol·m^-2·m^-1。从玉米大喇叭口期至玉米灌浆中期，全膜覆盖处理Tr均明显高于半膜覆盖和不覆膜处理。高—水处理下，全膜覆盖、半膜覆盖处理Tr平均分别达到10.1和8.2mmol·m^-2·m^-1。玉米叶片光合和蒸腾是两个相互协调、密切耦合的过程。全膜覆盖条件下，玉米全生育期WUEl对灌水量并不敏感；同等灌水处理下，不覆膜处理WUEl显著高——于全膜覆盖处理。Tr与An存在显著的正相关关系。WUEl和WUEE.TB之间、WUEl和WUEET.Y之间相关关系并不显著。（5）地膜覆盖和灌水对玉米全生育期0³0cm土壤含水率存在明显影响，而对30¹10cm土壤含水率的影响不明显。不同地膜覆盖和灌水条件下，玉米农田耕层（0³0cm）土壤温度表现出与气温变化趋势明显的一致性。采用地膜覆盖技术和在增加土壤含水率的同时，实现了土壤温度的同步提高，土壤含水率与土壤温度呈负负相关关系。耕层（0-30cm）土壤积温与土壤含水率与玉米全生育期平均叶片水分利用效率（WUEl）呈显著的负相关关系。更多还原

【Abstract】 Recently, studies on water use efficiency based on grain yield have been widelyreported while it still lacks systematic theoretical basis for effective water-savingmethods in agronomy. It is seriously considered that studies on effects of plasticmulching on soil thermo-hydraulic characteristics on farmland scale were on theurgent agenda. Besides, phase water use efficiency at various growth stages of maizeis still lack of systematic evaluation. Field maize was taken as research object inShiyang River Basin, one of most water deficient regions in Hexi Corridor, Gansuprovince. A field experiment was carried out to investigate the effects of differentmulching and irrigation regimes on soil thermo-hydraulic characteristics, and therelationship between phase water use efficiency based on biomass accumulation（WUEET.B） and WUE based on grain yield （WUEET.Y）, as well as key factors impactingWUEET.Band WUEET.Y. Main results were concluded as follows:1. Grain yields under whole mulching with high irrigation level, whole mulchingwith moderate irrigation level, and half mulching with high irrigation level on aridland were achieved to13275.5,12880.5, and12409.9kg ha-1, respectively. This wasattributable to improved kernel number,100-kernel weight, and double cob rate underthose three treatments. Irrespective of mulching patterns, high irrigation levelincreased those three yield components compared to moderate and low irrigation level.Whole mulching with high irrigation level significant increased those three yieldcomponents, with their values averaging659kernels per cob、36.4g per100-kernel,and23.9%, respectively. Irrespective of irrigation regimes, whole mulching increasedthose three yield components and leaf areas per plant.2. Plastic mulching and irrigation regimes had significant effects on phase andtotal water consumption. Total water consumption increased as the irrigation quotaincreased, reached the maximum at high irrigation level followed by moderate levelwhile the minimum was taken from maize at low irrigation level. Effect of differentmulching on water consumption was insignificant （P <0.05） under the same irrigationlevels. Under whole mulching condition, high and moderate irrigation levels increasedwater consumption by25.3and13.5%as compared to low irrigation level whileunder half mulching the percentage increases in water consumption were25.2and 11.7%, and, under no mulching treatment, were28.4and14.3%. From seedling tojointing, phase water consumption was highest in no mulching followed by halfmulching and lowest in whole mulching. However, from jointing on, phase waterconsumption was increased as the irrigation quota increased.3. Deficit irrigation is an effective way to improve water use efficiency, as wellas the WUEET·B. Under the same irrigation quota, whole mulching obtained the highestWUEET·Yfollowed by half mulching and no mulching resulted in the lowest WUEET·Y.WUEET·Ywas highest in maize under whole mulching with low irrigation level,averaging at19.9kg ha-1mm^-1while was lowest under half mulching with highirrigation level, averaging at13.3kg ha-1mm^-1, a decline by33.2%compared to theformer treatment. There was a positive correlation between WUEET·Yand WUEET·Bduring bell mouthed to filling. In contrast, there existed significantly negativecorrelation between WUEET·Band corresponding ET, E, and E/ET during seedling tojointing, and bell mouthed to flowering, respectively. Similar treatment effect wasalso observed between WUEET·Yand corresponding ET, E, and E/ET.—4. Transpiration rate （Tr） is not susceptible to irrigation quota under the same—mulching treatment across the growing season while the response of Tr to mulchingpatterns was significant （P <0.05）, irrespective of irrigation levels. Under wholemulching condition, photosynthetic rate peaked at heading stage while the maximu—rate appeared at middle filling stage under half or with no mulching. An under wholemulching with moderate irrigation was highest across treatments during growing—season (averagely47.0mmol m^-2m^-1). Tr under whole mulching was significantlyhigher than that of half and no mulching during bell mouthed to filling. Under high—irrigation level, Tr under whole and half mulching was10.1and8.2mmol m^-2m^-1,respectively. Leaf photosynthesis and transpiration were the processes that showedsynergistic effect and closely coupling between them. Under whole mulchingcondition, WUElwas not susceptible to irrigation quota, whereas WUElwith nomulching was significantly higher than that of whole mulching under the same——irrigation level. There was a positive correlation between Tr and An whilecorrelation between WUEland WUEE.TB, and WUEland WUEET.Ywas not significanteven at P <0.05. 5. Mulching and irrigation significantly influenced soil water content in the0-30cm soil profile while the effects on soil water content in the30-110cm soil profilewas insignificant （P <0.05）. Soil temperature at0-30soil depth simultaneouslychanged with air temperature. Thus mulching treatment not only improve watercontent in top soil, but also increased soil temperature at0-30cm depth while itexhibited a negative correlation between soil water content and soil temperature at agiven depth. There were negative correlations among accumulated soil temperature at0-30cm layer and soil water content and WUEl.更多还原