【作者】 吴忠东；

【导师】 王全九；

【作者基本信息】 西安理工大学 ， 环境工程， 2008， 博士

【摘要】 微咸水合理利用是实现农业水土资源可持续利用的主要途径之一。本论文在借鉴国内外微咸水地面灌溉研究成果的基础上,采取了室内、田间试验与模型模拟相结合的方法,以河北省沧州市南皮县微咸水田间畦灌试验为例,研究了微咸水入渗特征、对土壤理化性质和作物生长的影响以及合理的田间灌溉制度等内容,取得如下结论：(1)在系统分析微咸水入渗特征基础上,对具有明确物理意义的入渗公式对描述微咸水入渗特征可行性进行了研究,结果显示Green-Ampt模型和一维代数模型均可较为准确地描述微咸水入渗过程,但与实测值的误差随着矿化度的升高逐渐增大,一维代数模型对于参数的精度要求比Green-Ampt模型更高。(2)在入渗水矿化度为3g／L条件下,微咸水的钠吸附比对土壤含盐量无明显影响,但钠吸附比高于8.18 (mmol/L)0.5时会导致Na+成为土壤溶液中的优势阳离子,可使部分交换性Ca2+、Mg2+被Na+所取代,最终结果会导致土壤在亚类分级上向碱化土壤发展。(3)通过3年的淡水灌溉试验显示,旱作处理从拔节后均处于土壤干旱状态,所以在灌区进行补充灌溉是必要的,冬小麦最佳耗水量是508.04mm,对应的最高产量为6904.15 kg／hm2；生育期降水量一般年和湿润年灌水量为210mm时含水率边际效用最大,偏旱年灌水量为270mm时有最大边际效用。(4)通过3年的微咸水地面混灌试验结果分析显示,无论从土壤水盐分布和作物产量来看,采用3g/L微咸水灌溉相对比较安全,4g/L以上的微咸水会造成土壤的碱化趋势；咸淡轮灌试验结果显示,对于河北冬小麦而言,生育期采用1(次)咸2(次)淡轮灌处理,最佳灌溉次序为淡(拔节水)淡(抽穗水)咸(灌浆水),采用2咸1淡轮灌处理的最优灌溉制度为咸(拔节水)淡(抽穗水)咸(灌浆水)。(5)微咸水胁迫灌溉导致土水势下降,土壤孔隙被空气充满,使养分扩散路径的曲折度增加,影响作物产量。随着缺水阶段的后移,土壤水分得到了高效利用,且水分胁迫对株高、叶面积指数和产量及构成因素有滞后效应,因此应尽量将胁迫阶段后置。(6)微咸水波涌灌在可以使水盐分布在畦首～畦尾方向上离散度更小,微咸水传统地面畦灌产量比波涌灌有显著降低；采用SRFR模型对灌水效率和均匀度进行分析,显示当田面坡度为0.15%、畦长为200～250m、入畦流量为3.0～4.0L／m.s、周期数为3、循环率为1／3、单次供水时间为30min时,进行波涌灌能达到最高的灌水质量。更多还原

【Abstract】 Rational utilization of saline water is one of the main paths to realize sustainalbe utilization of water and soil resource. On the basis of using for reference of saline water surface irrigation research findings both abroad and home, the paper took saline water border irrigation in Hebei province Cangzhou City Nanpi County for the case and adopted adjoint method of both indoor and field experiments, study the impact on saline water seepage characteristics, soil physicochemical properties as well as rational field irrigation procedure and others, it made conclusions as below:(1) On the basis of systematic analysis of saline water infiltration characteristic, study on feasibility of describe saline water infiltration characteristic by infiltration formulation which possess definite physical significance, it showed that both Green-Ampt Model and one-dimension Algebraic Model can relatively exactly describe saline water infiltration process, but deviation building up in company with mineralization degree uprising, parametric accuracy requirement of one-dimension Algebraic Model is higher than that of Green-Ampt Model.(2) When mineralization degree is 3 g/L, Sodium Adsorption Ratio has little effect on soil salinity, but Na+will be dominant cation in soil solution when sodium adsorption ratio is more than 8.18 (mmol/L)0.5, it will make part of exchangeable Ca2+and Mg2+was substituted by Na+, final result is soil evolute to solonetzic soil in subclass classification.(3) It made a conclusion that dry farming all existed in soil drought state after jointing period by three years fresh water irrigation tests, so it is necessary to carry out supplemental irrigation in irrigation district, it is 508.04mm to winter wheat optimal water consumption, corresponding maximum production is 6904.15 kg/hm2; when precipitation rate is 210mm the marginal utility is maximum both in commonly and humidity year within growing season, precipitation rate is 270mm has maximal marginal utility in relatively drought year.,(4) Through three years’ saline water surface blending irrigation test results analyses, it showed that 3 g/L is relatively safety whether from soil water salinity distribution and crop yield, soil tend to alkalization when saline water mineralization degree is more than 4 g/L; rotational irrigation showed that optimal irrigation procedure is fresh (jointing water) fresh (tassel water) salty (grouting water) when growing season came into use once salty twice fresh water, optimal irrigation procedure is salty (jointing water) fresh (tassel water) salty (grouting water) when twice salty once fresh water was used.(5) Soil water potential descended by saline water stress irrigation and soil pore is full of air, it makes the tortuosity of nutrient diffuse path increased, and impact the crop yield. Soil moisture obtain high efficiency utilization in company with the backward shift of water shortage stage, and plant height, leaf area index and yield water stress have hysteresis effect by water stress, therefore stress stage should postposition.(6) Both moisture content and salt content has a smaller dispersion alonge the border head to border tail by saline water surge flow irrigation, yield decreased significantly irrigated by saline water traditional surface border irrigation than that of surge flow irrigation. Both irrigation efficiency and irrigation uniformity were analyzed by SRFR Model, it showed that when the field slope gradient is 0.15%, border length is 200-250m, unit width flux is 3.0～4.0L/m.s, periodic numbers is 3, circulation rate is 1/3, water supply time in one period is 30 min, surge flow irrigation can obtain maximal irrigation degree.更多还原