【作者】 郭秀峰；

【导师】 肖娟；

【作者基本信息】 太原理工大学 ， 农业水土工程， 2013， 硕士

【摘要】 负压灌溉可以利用土壤基质势(土壤吸力),从比灌水器低的水源自动吸取水分,提供给作物和土壤且无需提水加压设备,在节约能源的同时降低了灌溉成本。利用咸水进行灌溉不仅可以利用咸水资源,降低地下水位,同时对改善土壤特性也有很大作用。试验采用30°等腰三角形柱体有机玻璃土箱,高40cm,腰长35cm。灌水器采用具有透水不透气特性的多孔陶土板(5cm×3cm×2.5cm),孔径为3-4μm,用马氏瓶对系统进行恒压供水。主要研究了不同供水水头(H=0m、-0.5m、-1.0m、-1.5m)和不同灌溉水质(C=80meq/L、20meq/L、2meq/L,SAR=20、10)对负压灌溉土壤水分和盐分运移及分布的影响,结果表明：(1)灌溉水质相同的情况下,供水水头越小,相同灌水时间内湿润体的体积越小；不同供水水头的累计入渗量Q、最大水平湿润距离X和最大垂直湿润距离Z均随时间的增加而增加；灌水时间相同时,宽深比随供水水头的增加而增加,且增加幅度随供水水头的减小而减小；离灌水器越远的地方,含水量越小,含盐量越大；同一取样点的含水量随供水水头的减小而减小,盐分含量随供水水头的减小而增大。(2)在不同水质下,灌溉水浓度较高和钠吸附比较大的湿润锋、累积入渗量、最大水平湿润距离和最大垂直湿润距离都随供水水头的减小而增大。供水水头降低有利于高浓度水和钠吸附比大的水灌溉。供水水头较小时,低浓度和钠吸附比较小的宽深比比较大。总体上灌溉水质对宽深比的影响不大,宽深比都在0.6-0.8之间。负压灌溉湿润体内含水率的分布近似为一组同心椭球面,含水率最大值分布在椭球中心,土壤电导率最大值分布在湿润体边缘,湿润体的平均含水率随着SAR的增加而减小,湿润体平均电导率随着SAR的增加而增加。更多还原

【Abstract】 As a new type of water-saving irrigation technology, the negative pressure irrigation system can draw water automatically from water source below emitter by soil matric potential (soil suction). This irrigation system can save energy and reduce the cost. Saline water irrigation can not only use salt water resources, re-duce the underground water level, but also can improve the quality of soil.The further tests are carried out on the basis of predecessors’ research.The30°wedge-shaped organic glass containers were remaining used. Its height is40cm and radial length is35cm.we use porous argil board as diameter-water de-vice (aperture is3-4μm and the size is5cm*3cm*2.5cm). Graduated cylinders were used to keep constant water head. A series laboratory experiments were arranged to study the effects of different water head (H=0m、-0.5m、-1m、-1.5m)and different water quality (C=80meq/L、20meq/L、2meq/L, SAR=20、10).The experimental results indicated that:(1)Under the same water quality, the lower water head, the smaller wetted soil volume. The cumulative infiltration rate, maximum horizontal and vertical wetted distance all increases with time. The greater the distance from emitters, the lower the water content under all treatments. At the same level, ratio of width to depth increases with the increase of water head, and the increase range decreases with the decrease of the water head. Water moisture decreased with the decreasing of water head. On the contrary, the greater the distance from emitters, the higher salt concentration under all treatments. Salt concentration increased with the decreasing of water head.(2) Under different water quality, the cumulative infiltration rate, wetting front maximum horizontal and vertical wetting front increase with the decrease of the water head when salt concentration and sodium adsorption ratio are high. Lower water head is advantage to the high salt concentration and sodium ad-sorption ratio of irrigation. On the low water head, the ratio of the width and depth is large when salt concentration and sodium adsorption are small. On the whole, the influence of water quality on the ratio of the width and depth is not big, the range is between0.6to0.8.The distribution of water content and electric conductivity in wetted soil volume may be described as a series of concentric ellipsoid, the maximum moisture content distribution in the center of the ellip-soid and the maximum electric conductivity distribution in the margin. With the increasing of SAR, average soil water content decrease and average electric conductivity increase.更多还原