【作者】 王磊；

【导师】 胡笑涛；

【作者基本信息】 西北农林科技大学 ， 水利工程（专业学位）， 2014， 硕士

【摘要】 农田土壤水分动态变化规律、有效性评价和土壤水分运动的模拟长久以来一直是干旱半干旱地区的研究热点问题，是灌溉预报和节水灌溉科学管理的理论依据。本论文对甘肃武威石羊河流域的春小麦、春玉米和裸地等不同作物类型农田土壤水分动态变化规律进行研究，评价了农田土壤水分的有效性,在此基础上，构建了农田分层土壤水分运动模型，并对模型进行了验证，获得以下主要结果：（1）石羊河流域裸地、春小麦地和春玉米地土壤水分受降水（灌溉）、蒸发蒸腾和土壤水分运移等影响变化幅度均较大，裸地和春小麦、春玉米两种作物类型的农田相比，其土壤水分变化的剧烈程度较小，深层（80-100cm）土壤水分基本保持稳定，而作物覆盖的农田深层(80-100cm)土壤含水率变化幅度较大，主要是受到作物根系吸水的影响；农田蒸发蒸腾量受土壤水分含量影响较大，土壤水分含量长时间处于较低水平会导致农田蒸发蒸腾量大幅度减少。（2）在当地灌溉制度条件下，春小麦作物根系层水分整个生育期内基本为“中等有效”，对春小麦生长有利；春玉米作物根系层内的水分在生育期内则由“易效”转为“难效”，而且随着土层的加深，土壤水有效性由“易效”转为“难效”的时间依次推后，即在春玉米生长期内，即在春玉米生长期内，随着作物根系的生长，深层土壤中储存的有效水量将逐渐被春玉米吸收利用。（3）提出了分层土壤含水率对作物蒸发蒸腾量影响的评估模型，对春小麦和春玉米不同土层的土壤含水率对作物蒸发蒸腾的影响程度进行了评价，春小麦表层和浅层土壤（0-30cm）的水分状况对作物生长影响最大；春玉米浅层和中层土壤（10cm-80cm）水分状况对其生长影响程度最大。（4）构建了春小麦抽穗-成熟期农田土壤水分分层运动模型，经验证，30-80cm土层土壤水分动态变化模拟精度较高，上层和深层土壤水分动态变化模拟精度较差。更多还原

【Abstract】 Soil moisture dynamic variation, simulation and evaluation of the effectiveness of soilmoisture and the simulation of water movement has long been a hot topic in arid andsemi-arid regions, it is the theoretical basis for forecasting and scientific management ofwater-saving irrigation. In this paper, we studied the dynamic variation of soil moisture inspring wheat, spring corn and bare farmland, lacated in Shiyang River Basin, Gansu Wuwei.And we evaluated the effectiveness of the soil moisture. It build a core of farmland soil watermovement hierarchical model, the model was validated. Obtain the following main results:(1)In Shiyang River Basin， bare land, spring wheat and spring corn farmland’s soilmoisture is impacted by precipitation (irrigation), evapotranspiration and soil moisturemigration and other reasons, so they changed quickly. Bare land and spring wheat, two typesof spring maize crop farmland compared to the dramatic changes in soil moisture lesser extent,deep (80-100cm) soil moisture remained stable. The crops covered farmland deep (80-100cm)soil moisture is still a large degree of change, affected crop root water uptake, there are cropsfarmland soil moisture changes include more severe soil deep. Evapotranspiration influencedby soil moisture content, soil moisture content at a low level for a long time will lead to asubstantial reduction in evapotranspiration.(2)Under the conditions of the local irrigation system, basic water spring wheat crop rootzone for the entire growth period "effective medium", on spring wheat growth beneficial;moisture in the root zone of spring maize crop in the period from birth "easy effect" to"difficult after effect ", and with soil depth, soil validity of the" easy effect "to" hard effect "oftime in order to push that growth period in the spring corn, deep soil water will be less andless effective increasingly difficult to crop use.(3)Build a hierarchical model to assess soil moisture effects on crop transpirationevaporation. And application of the model soil moisture in spring wheat and spring maizecrop in different soil evaporation and transpiration of impact were assessed. The resultsshowed that: For spring wheat, surface and shallow soil (0-30cm) of water status greatestimpact on crop growth; for maize, shallow and middle soil (10cm-80cm) of water statusmaximum impact on growth (4) Construction of the spring wheat heading-maturity stage of farmland soil moisturelayered motion model, and verified by simulation; the dynamic changes of soil water30-80cmis high precision and the upper and deeper soil moisture is poor precision.更多还原