【作者】 叶校飞；

【导师】 解建仓； 王涛；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2010， 硕士

【摘要】 土壤盐碱化是目前世界旱地农业面临的四大生态环境问题之一。传统的盐碱地治理依靠“大水压盐、洗盐,地下排水”的方法,将下渗的土壤盐分通过地下排水的方法排水洗盐。“以排为主”的做法使区域得到治理的同时,也存在不少问题,如灌排工程量大,费用高且灌排工程施工烦琐,系统需要外界持续人工干预；洗盐排水消耗过多水资源,不利于节水；区域地下水位下降,气候趋于干旱；排走的盐碱水污染了下游水源等问题。基于盐碱水也是一种水资源的理念,提出了“改排为蓄”治理模式,并在卤泊滩10年的治理实践中得到很好的应用,治理效果非常好。本文从长期不定期田间盐分观测试验说明了盐分的大体变化趋势,并从盐分扩散角度分析和设计了水体—相邻土壤水盐运移室内模拟试验,以此来求证蓄水条件下盐分在水土中扩散的方向及强度,为蓄水条件下盐碱地治理模式提供强有力的支持。主要结论有：1通过长期田间试验观测资料显示,从1999—2008年,耕作层土壤盐分由刚整理结束时的0.465%降低到0.210%,pH值由9.54降低到8.35,盐碱化问题得到很好的解决；Cl-、S042-、HC03-等离子都得到大幅降低,有机质含量0.463%提高到1.18%,土壤得到有效改善,由重度盐碱地改造成为高产的良田。从实际效果说明了改排为蓄盐碱地治理模式是可行的。2水体—相邻土壤盐分运移试验结果表明,在蓄水条件下,土壤浸提液的盐分浓度由0.494%减少到0.34%,水体盐分浓度由0.07%增大到0.339%,盐分由土壤扩散到水体中,说明蓄水条件下可以减少土壤的含盐量。3由改进后的室内水体—相邻土壤盐分运移试验可知,与水体水平距离越接近的土壤,其含盐量变化越快,反之,与水体水平距离越远的土壤含盐量变化越慢,主要是因为土壤具有一定的吸附性,对盐分的运移有一定的阻力,盐分在土壤中运移需要一定的时间,我们认为,蓄水沟对田块土壤盐分的影响有一定的范围,超出这个范围,蓄水对土壤盐分的影响将会变得很小。4循环压盐模拟试验结果表明,通过蓄水深度和水体盐分浓度的循环变化,可以使上层土壤的盐分减少,下层土壤盐分增多,改变土壤盐分在垂直空间上的分布,可以达到加速压盐的效果,使土壤盐分快速的向下迁移。更多还原

【Abstract】 Soil salinization is one of the four environment problems that the dry farming faced to in the world. The traditional saline soil treatment take the method of "wash the salt by Plenty of water、underground drainage". Take away the salt infiltrat from surface soil by underground drainage. The saline treatment method based by row has many problems when the saline soil get improved. Such as, so big of irrigation and drainage engineering quantity, input costs running costs maintenance costs are very high, and the construction is very tedious, the system need sustained external manual intervention, wash the salt and drainage cost too much water, the regional groundwater level decreased, the climate tends to drought; The saline water drained away pollute the downstream, and so on.Based on the concept of saline water is also water resources, "change drainage to impoundment" treatment model was proposed, and was applied very well in LuBoTan ten years practice. The paper showed the change trend of salt according the long—term field observation experiment, analysed the salt diffusion between water and adjacent soil and designed laboratory simulation experiment. Demonstrated the direction and intensity of salt diffusion, give the strongly support for the "change drainage to impoundment" treatment model, the main achievements were:1、the observation datas of long-term field observation experiment showed that the soil salinity was declined from 0.465 percent to 0.210 percent, The pH value were decreased from 9.54 to 8.35, the ions such as Cl-、SO42-、HCO3- were lower than initial value, the soil organic matter content was increased to 1.18 percent from 0.463 percent, the soil quality got improved, the serious saline-alkali land became high yielding fertile farmland. It illustrateed "change drainage to impoundment" treatment model was feasible by the practical effect.2、the results of water—the adjacent soil salt transport experiment in laboratory showed that the soil salt was reduced, the total salt of water was increased, the salt diffusion from soil to water, the more nearly to the water the soil salinity changed more obviously. 3 the results of improved water—the adjacent soil salt transport experiment in laboratory showed that the soil closer to water the soil salinity changed faster. The main reason was soil has a certain adsorption, it can impede salt transport in soil.We consider that the impact to soil salinity of ditch water is limited, there was a maximum range in the horizontal direction.4、the results of taking the salt from upper soil to subsoil by cyclic changing water level experiment in laboratory showed that according changing the salt concentration and water level can make the salt in upper soil reduce and the salt in subsoil increase. Changed the soil salinity distribution in the vertical spatial, took the salt from upper soil to subsoil.更多还原