黄河三角洲滨海盐渍土水盐运移特征与调控技术研究

发布时间：2018-04-29 10:02

本文选题：黄河三角洲 + 盐碱土　；参考：《中国科学院烟台海岸带研究所》2017年硕士论文

【摘要】：黄河三角洲地区农业发展中严重缺乏优质的水土资源,规模化开发利用该地区丰富的滨海盐渍土资源是保证农业可持续发展的有效途径,滨海盐渍土开垦过程中的水分高效利用是盐渍土改良的重要内容。本研究以黄河三角洲腹地垦利县为研究区域,通过野外布设监测点,观测县域尺度上土壤和地下水的水盐运移情况,同时布设室内试验,分析不同地下水位对蒸发和土壤表层积盐的影响;分析土壤在不同盐度淋洗水以及不同淋洗方式作用下,盐渍土脱盐规律与可溶离子迁移行为,对改善土壤盐渍化过程中的水盐动态机制进行了初步探究,为今后盐碱地的改良工作提供可靠的科学依据和技术指导。主要研究结果如下:黄河三角洲地区的地下水水位较低,受降雨和潜水蒸发的影响,年内地下水埋深为0.7~2.37 m;农田和荒地的地下水电导率变化范围基本在20.21~29.80mS/cm和44.79~48.62 mS/cm之间;地下水埋深和电导率二者变化同步。在连续淋洗和间歇淋洗条件下,完全脱盐需淋洗水量分别为550 mm~900mm和350 mm~700 mm,达到一般农作物(计划湿润层为0~60cm)生长所需淋洗水量分别为472.70 mm和411.60 mm,间歇淋洗比连续淋洗节约用水14.8%。因此为了更高效的利用灌溉淡水资源,选择间歇淋洗的方式进行计划湿润土层脱盐更为适宜。黄河水和微咸水淋洗脱盐水量分别为550 mm~900 mm和460 mm~1125mm。微咸水达到淋洗终点时,除了土壤总盐量达到植物所需外,并且可溶盐的离子组成也较为合理,并且对植物根系伤害较为显著的Na+和Cl-离子浓度都降到0.03 mol/L和0.05 mol/L以下。因此,微咸水灌溉也可以使土壤达到良好的生境,达到一般农作物(计划湿润层为0~60 cm)生长所需。黄河水和微咸水淋洗脱盐水量分别为472.70 mm和754.20 mm。当地下水埋深为100 cm和140 cm时,蒸发返盐分别需要55 d和116 d达到一般植物生长对土壤盐分的耐盐极限;随着表层盐壳的形成,对蒸发产生了抑制作用,平均蒸发强度分别为11.27 mm/d和7.52 mm/d。不同地下水埋深条件下,Na+和Cl-离子向土柱表层积聚速度最快,且富集的浓度最高。在黄河三角洲地区垦利县主要作物小麦、玉米和棉花的净灌溉需水量为442 mm、133 mm和353 mm,种植面积比例分别为7.59%、9.35%和60.84%。三种主要作物的毛灌溉需水量分别为3384万m3、1033万m3和21664万m3,占用水量的比例分别为12.98%、3.96%和83.06%。
[Abstract]:There is a serious lack of high quality soil and water resources in the agricultural development of the Yellow River Delta. The effective way to ensure the sustainable development of agriculture is to develop and utilize the rich coastal saline soil resources in this area on a large scale. The efficient use of water in the reclamation process of coastal saline soil is an important content in the improvement of saline soil. Taking Kenli County, the hinterland of the Yellow River Delta, as the study area, the water and salt migration of soil and groundwater on the county scale was observed by setting up monitoring points in the field, and an indoor experiment was conducted at the same time. The effects of different groundwater levels on evaporation and soil surface salt accumulation were analyzed, and the desalination law and soluble ion migration behavior of salinized soil under different salinity leaching water and different leaching methods were analyzed. The mechanism of water and salt dynamics in the process of soil salinization was preliminarily explored in order to provide reliable scientific basis and technical guidance for the improvement of saline-alkali land in the future. The main results are as follows: the groundwater level in the Yellow River Delta is relatively low, and the groundwater depth is 0.7 ~ 2.37 m under the influence of rainfall and phreatic evaporation, and the variation range of groundwater conductivity in farmland and wasteland is basically between 20.21~29.80mS/cm and 44.79 ~ 48.62 mS/cm. The groundwater depth and conductivity change synchronously. Under the condition of continuous leaching and intermittent leaching, the washing water required for complete desalination was 550 mm~900mm and 350 mm~700 / mm, respectively, which reached 472.70 mm and 411.60 mm respectively for the growth of general crops (the planned wet layer was 0 ~ 60 cm). The water saving of intermittent leaching was 14.8 mm than that of continuous leaching. Therefore, in order to make more efficient use of irrigated fresh water resources, it is more appropriate to choose the intermittent leaching method to plan the desalination of wet soil. The amount of desalination in Yellow River water and brackish water is 550 mm~900 / mm and 1125mm / m respectively. When brackish water reaches the end point of leaching, besides the total salt content of soil reaches the plant demand, the ion composition of soluble salt is also more reasonable, and the Na and Cl- ion concentrations, which are more significant to plant root system injury, are all decreased to 0.03 mol/L and below 0.05 mol/L. Therefore, brackish water irrigation can also make the soil reach a good habitat and meet the needs of general crops (the wet layer is planned to be 0 ~ 60 cm). The amount of desalination in Yellow River water and brackish water was 472.70 mm and 754.20 mm respectively. When the groundwater depth is 100cm and 140cm, it takes 55 days and 116 days to reach the salt tolerance limit of the general plant growth to soil salt, and the evaporation is inhibited with the formation of the surface salt shell. The average evaporation intensity was 11.27 mm/d and 7.52 mm / d, respectively. The accumulation rate of Na and Cl- ions to the surface of soil column is the fastest and the concentration is the highest under different groundwater depth. The net irrigation water requirement of wheat, corn and cotton in Kenli County of the Yellow River Delta is 442 mm ~ 133 mm and 353 mm respectively, and the proportion of planting area is 7.599.35% and 60.84 mm respectively. The gross irrigation water requirements of the three main crops were 33.84 million m ~ 3, 10.33 million m ~ 3 and 216.64 million m ~ 3, respectively, and the proportion of water consumption was 12.98% 3.96% and 83.06%, respectively.
【学位授予单位】：中国科学院烟台海岸带研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.42

【相似文献】