共查询到19条相似文献，搜索用时 750 毫秒
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分析了洮儿河灌区运行后土壤次生盐渍化问题,及产生土壤次生盐渍化的条件,影响因素,并提出有效的预防措施,使农业灌溉向良性发展. 相似文献
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电磁感应方法在土壤盐渍化评价中的应用研究 总被引：20，自引：2，他引：20
本文应用电磁感应方法（大地电导率探测仪EM38），对新疆焉耆盆地的土壤电导率进行了测量，分析了电磁感应方法所得结果和土样分析结果之间的相关关系，证实了电磁感应方法的有效性。基于电磁感应方法测量的结果，对新疆焉耆盆地土壤盐渍化进行了定性评价。结果表明，在开都河上游，土壤盐渍化程度普遍较轻：在中游地带，灌医内的上壤盐渍化改良取得了一定的成效，土壤中的含盐量较低，但是在远离河谷的非灌区，土壤含盐量依然很高；在下游及靠近博斯腾湖的地区，土壤含盐量普遍较高，并有随深度增加而增加的趋势。 相似文献
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分析土壤盐渍化与地下水特征之间的关系对区域水土资源可持续利用具有重要意义,同时也为地下水资源管理的科学化和现代化提供技术支撑。利用136个土壤剖面的540个土壤样品及相应地下水观测数据,采用对数正态分布模型,对伊犁河流域地下水埋深、矿化度对土壤盐渍化的影响进行了研究,计算分析了防止土壤盐渍化的地下水临界深度。结果表明:研究区表层土壤含盐量随地下水矿化度的增加呈指数增加的趋势;各土层含盐量随地下水埋深的增加呈对数下降的趋势;当地下水矿化度介于1~3g/L、3~6g/L、6~10g/L与1~10g/L时,盐渍化土壤出现频率峰值所对应的地下水埋深分别为1.44 m、1.65m、1.83m与1.63m。为了防止土壤次生盐渍化,当地下水矿化度介于1~3g/L、3~6g/L、6~10g/L与1~10g/L时,地下水埋深分别控制在2.06m、2.49m、2.66m与2.24m以上。地下水矿化度越大,可在较大的地下水埋深范围内发生土壤盐渍化。对数正态分布模型分析结果与对数拟合曲线分析结果基本一致,说明研究结果是可靠的。地下水埋深2.5m可作为防止土壤盐渍化的临界地下水埋深。 相似文献
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半干旱地区土壤水盐动态的特征是：盐渍与旱涝相联系；旱季蒸发和盐与雨季淋溶脱盐两种过程交替发生；土壤与地下水水盐运动相互作有。防治土壤盐渍化，不仅要调控土壤根层盐渍度不超过作物耐盐国界值，而且要调控地下水埋深在临界动态；即旱季在防治盐渍化的临界深度（2－3m）；雨季前在防涝蓄雨深度（4－6m），雨季在作物抗湿深度（0．5－1．0m）。最大限度地把天然降雨转化为可利用的水资源，使旱涝盐渍得到综合治理。目前海河平原已有大面积盐渍土得到改良，但还存在潜在盐渍化土壤。土壤根层盐渍度已低于作物耐盐度，但有的心底土盐分重，或地下水矿化度高，一旦地下水位升高仍会发生盐渍化。这个地区又是引黄或引江灌区所在，调控地下水埋深在临界动态，是预防灌溉次生盐渍化发生地关键。 相似文献
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银北地区土壤盐渍化形成机理与模拟研究 总被引：1，自引：1，他引：1
银北地区位于干旱、半干旱气候带,降水稀少,蒸发强烈,导致本地区土壤盐渍化严重。近年来,由于黄河来水量的逐年减少,引黄灌溉不能满足农业灌溉需求,逐渐开始开采利用地下水。由于银北地区浅层地下水矿化度较高,利用地下水灌溉可能引起次生土壤盐渍化。本文运用PHREEQC模型软件模拟灌溉水与土壤之间的相互作用过程,探讨了土壤盐渍化的形成机理。通过模拟分析得到以下结论:(1)地表水和地下水联合运用是解决银北灌区土壤盐渍化的关键,不同地区采取不同的混合比例,可以实现水资源的高效利用。(2)银北地区灌溉淋洗期间存在蒸发浓缩叠代在2~4次,说明存在轻微蒸发。(3)INVERSE模拟结果说明,银北地区灌溉淋洗期间存在轻微蒸发,水相和固相的相互作用,石膏、白云岩和盐岩溶解,Na 、Ca2 和Mg2 吸附交换,渠水下渗转化为地下水;非灌水期地下水通过毛细管作用强烈蒸发,水相和固相的相互作用,石膏、白云岩和盐岩沉淀,Na 、Ca2 和Mg2 解吸附,使有害盐分氯化物、硫酸盐存留在土壤层中,形成土壤盐渍化。 相似文献
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在系统分析以往地质地质资料的基础上，借助ETM卫星图像，提取臭水泉群的分布信息，通过野外实地调查、访问、取样化验，初步查明六盘山地区的臭水泉主要分布于马东山复背斜的南北两端及东西两翼，以上升泉的形式出露于沟底，中、新生代高含盐量地层是臭水泉群中盐分的物质来源，北东向、北东东向、近南北向断裂和构造裂隙是臭水溢出的通道。臭水泉流出的高矿化度咸苦水及H2S气体，已造成的局部大气质量下降，地表水体和河谷潜水矿化度升高，土壤盐渍化，严重影响了当地人民的生活。 相似文献
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黑龙江省松嫩低平原区盐渍化地球化学特征 总被引：4，自引：2，他引：2
根据松嫩低平原区多目标地球化学调查成果,以松嫩平原土壤中盐渍化主要组成元素为研究对象,通过元素含量变化和元素间的相关关系,探讨了盐渍化地区元素分布分配的地球化学规律。盐渍化土壤存在pH值的临界区间,盐渍化的强弱与 Cl、S、Na等元素的含量密切相关。盐渍化与土壤沙化在空间上交互作用,共同造成本地区土壤的退化。松嫩平原无论表层土壤还是深层土壤中,Cl的平均含量比较低,导致Cl在土壤中局部强烈富集,可能与地下水化学类型与高矿化度相关。
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本文重点阐述由于不合理灌溉引起潜水位上升，在特定的气候，地形地貌，地层岩性诸因素综合作用下，导致土壤次生盐渍化问题，并对次生盐渍化的影响因素，形成机理进行了分析研究，提出了相应的治理措施。 相似文献
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Geochemical and isotopic characterization of groundwater and lake-water samples were combined with water and total dissolved solids balances to evaluate sources of groundwater quality deterioration in eastern Hetao Basin, Inner Mongolia, China. Groundwater quality is poor; 11 of 13 wells exceed drinking-water guidelines for at least one health-based parameter and all wells exceed aesthetic guidelines. The well water is largely derived from Yellow River irrigation water. Notably high uranium concentrations in the Yellow River, relative to world rivers, suggest groundwater uranium and other trace elements may originate in the river-derived irrigation water. Complex hydrostratigraphy and spatial variation in groundwater recharge result in spatially complex groundwater flow and geochemistry. Evapotranspiration of irrigation water causes chloride concentration increases of up to two orders of magnitude in the basin, notably in shallow groundwater around Wuliangsuhai Lake. In addition to evapotranspiration, groundwater quality is affected by mineral precipitation and dissolution, silicate weathering, and redox processes. The lake-water and TDS balances suggest that a small amount of discharge to groundwater (but associated with very high solute concentrations) contributes to groundwater salinization in this region. Increasing salinity in the groundwater and Wuliangsuhai Lake will continue to deteriorate water quality unless irrigation management practices improve. 相似文献
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地下水是海原盆地唯一的供水水源,近年来部分地区地下水溶解性总固体(TDS)增高,引起了有关部门和水文地质工作者的高度关注。通过分析69组地下水样品的水化学和氢氧稳定同位素数据,对地下水补给来源和咸化的水文地球化学过程进行了研究。结果表明:地下水TDS值198.2~6 436.4 mg/L,沿着地下水流向,咸化程度增加,水化学类型从基岩区的HCO3—Ca·Mg型演化至滞留—排泄区的SO4·Cl—Na·Mg型。地下水补给来源主要为大气降雨和基岩裂隙水侧向径流,补给源—对地下水咸化贡献较小。溶滤作用具空间差异,基岩区和补给区以碳酸盐、硅酸盐风化为主,径流区和滞留—排泄区则为蒸发岩风化,硫酸盐是地下水中阳离子的主要来源。补给水、溶滤和蒸发对第四系地下水TDS的贡献比率分别为4.8%~81.2%、11.9% ~85.9%、1.7%~29.5%,溶滤作用是控制海原盆地地下水咸化的首要因素。当地有关部门应加大对基岩泉水的综合利用,同时注意控制海原县和西安镇等地区地下水开采量,防止地下水进一步咸化。另外,在微咸水分布区可引进地下水去除硫酸盐技术,提高微咸水利用程度。 相似文献
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ASTER遥感影像数据在土壤盐渍化评价中的应用 总被引：4，自引：0，他引：4
本文通过运用ASTER遥感影像数据，对不同地物进行光谱分析，根据不同地物在不同波段的光谱特征曲线，分别提取植被和水体信息，然后进行非监督分类。并结合物探试验和土样分析结果，进行聚类分析，定性和定量的评价了焉耆盆地内土壤盐渍化程度分布状况。评价结果为：在焉耆盆地的平原区内，非盐渍化土壤，457．65km^2；轻度盐渍化土壤，335．61km^2；中度-重度盐渍化土壤，580．93km^2；盐土，41．11km^2。根据野外实际调查，评价结果的精度达到了85％以上。 相似文献
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Maharlu Lake with Na–Cl water type is the terminal point of a closed basin in southern Iran. A total of 10 water samples from two rivers discharging to the lake and 78 water samples of surface and pore brine of Maharlu Lake have been collected from different depths (surface, 20, 50 and 100 cm) of four sampling stations along the lake during a period of lake water-level fluctuation (November 2014–July 2015). To investigate chemical interaction between lake surface water and shallow pore water and to understand the major factors governing chemical composition of Maharlu brine, concentrations of major and minor (boron, bromide and lithium) solutes, pH and total dissolved solids have been measured in collected water samples. Saturation indices of evaporite minerals in collected water samples have been also calculated. The chemical behavior of dissolved solutes and evaporative evolution of the lake brine during a hydrological period have been simulated using PHREEQC. The results of our investigations indicated that chemical composition of lake surface water and pore brine of Maharlu Lake are mainly connected with lake water-level fluctuations and distance from input rivers (and depth), respectively. Hydrochemical investigations and statistical analysis showed that the brines chemistry of Maharlu is mainly controlled by three processes: brine evaporative evolution, dissolution–precipitation and diagenetic evolution of secondary carbonates. 相似文献
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柴达木盆地盐湖众多,表土盐渍化和盐漠化极为发育,含盐表土经风吹蚀后产生的大量盐尘将危害盆地生态环境和人类健康。笔者在柴达木盆地中东部系统采集129个不同类型的表土样品,对其中盐类矿物成分及分布特征进行了分析。分析结果表明,表土中的主要盐类矿物是石盐、石膏以及少量的无水芒硝;盆地中东部含盐量高值区集中分布在尕斯库勒湖以东的一里坪盐湖、西台吉乃尔盐湖和东台吉乃尔盐湖周边以及中部格尔木—诺木洪一带绿洲前缘的区域;盆地不同表土的含盐量从高到低依次为干盐滩(盐壳)、雅丹、盐化草原、戈壁滩和沙漠。研究结果显示,雅丹和干盐滩很可能是盐尘暴的主要物源区,其他类型表土贡献较小;表土含盐特征及其分布规律可能受区域构造、盐湖演化、气候与水文等多种因素的影响。本文成果可以为柴达木盆地盐尘暴的形成机制和灾害防治等提供重要科学依据。 相似文献
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Land degradation in the source region of the Yellow River, northeast Qinghai-Xizang Plateau: classification and evaluation 总被引：6，自引：0，他引：6
Land degradation imposes a great threat to the world. It is not merely an environmental issue, but also a social and economic problem. Land desertification is among the main aspects of environment changes in the source region of the Yellow River. Previous studies focused on water resource utilization and soil erosion, but land degradation in the source region of the Yellow River even the whole Qinghai-Xizang Plateau received little attention. Based on the data obtained by field investigation and TM satellite images of 2000, this study provides the classification and evaluation information of the land degradation in the source region of the Yellow River. There are six types of land degradation in this region: water erosion in the northern mountains around the Gonghe Basin, sandy desertification in the Gonghe Basin and Upland Plain Area, aridization in the lower reaches, salinization in the Gonghe Basin, vegetation degradation in the intramontance basin and freezing and thawing erosion in the high mountains. The total degraded area is 34,429.6 km2, making up 37.5% of the land in the study area. Finally, land degradation in the source region of the Yellow River was evaluated according to changes in the physical structure and chemical component of soils, land productivity, secondary soil salt and water conditions. 相似文献
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张掖盆地地处甘肃省河西走廊黑河流域中游地区,地势南东高北西低。已有勘探资料显示,张掖盆地赋存丰富的水热型地热资源。通过研究该区域地球物理勘探、钻探、地温测量及水文地球化学等成果资料,分析了张掖盆地地热资源赋存特征,探讨了其成因模式。张掖盆地地热田属沉积盆地型中低温地热田,热储为呈层状分布的新近系白杨河组砂岩、砂砾岩,选择钾镁地球化学温标计算热储温度为47～82°C,盖层为新近系上新统疏勒河组泥岩及第四系松散地层;地热水类型主要为碎屑岩类孔隙水,根据氢氧同位素特征推断其主要补给来源为南部祁连山区大气降水;祁连山北缘深大断裂和盆地内NNW向基底断裂是地热流体深循环良好的导水通道,地下水接受补给后沿导水断裂带或岩层孔隙裂隙运移,在深部热传导的增温作用下,赋存于碎屑岩类孔隙之中形成了本区的地热资源。水质分析结果表明：本区地热水属于溶滤型的陆相沉积水,水化学类型为Cl·SO4—Na型,F-、SiO2、溶解性总固体、总硬度含量随水温的升高而增大;区内地热水3H值普遍小于2.0 TU,说明形成年代较早;14C分析结果进一步证实,区域地... 相似文献
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CORNEL OLARIU JANOK P. BHATTACHARYA MATTHEW I. LEYBOURNE STEPHEN K. BOSS ROBERT J. STERN 《Sedimentology》2012,59(2):704-728
Basin‐floor topography influences the flow path of hyperpycnal plumes and delta morphology during progradation of the Red River delta in Lake Texoma, USA. The Red River discharge is typically a hyperpycnal plume due to elevated total dissolved solids. Because the river plume is a bottom‐hugging hyperpycnal flow, lake bathymetry and topography strongly influence deposition and subsequent delta morphology. In addition to elevated total dissolved solid concentrations compared with Lake Texoma water, the density contrast of the Red River outflow is increased by high suspended‐sediment concentrations during high‐discharge events. Steep lateral slopes in the Lake Texoma basin deflect hyperpycnal river plumes and, subsequently, change the delta progradation direction before the delta reaches the opposite bank of the lake. Analysis of multi‐temporal aerial and satellite images indicates that the hyperpycnal delta follows the steepest lake‐bottom gradients, corresponding to the pre‐impoundment river thalweg (i.e. bypassing shallow parts of the lake). An analytical model for the hyperpycnal‐plume trajectory indicates plume deflection during low‐discharge or high‐discharge events, towards the deepest part of the basin. The magnitude of plume deflection is a function of river discharge and basin‐margin gradients. Plume deflection can vary between 10° and 80° from the channel axis towards the old river thalweg. The high deflection appears in the case of maximum basin side gradients of 12·8° and in conditions of low river discharge. During low‐discharge periods, the Red River delta builds a lobate shape with multiple terminal distributary channels whereas, during high‐discharge periods the Red River delta builds an elongate shape with a single large distributary channel. The elongate morphology of the delta is formed through the development of a single distributary channel and abandonment of the other distributaries. Therefore, the lobate shaped delta is expected to be preserved in the rock record. 相似文献