新疆阿拉尔地区土壤盐渍化特征

阿拉尔地区是重要的农业生产基地,由于研究区盐渍化程度及分布情况认识不足,制约了研究区的农业发展。针对阿拉尔地区盐渍化土壤现状,借助统计学与野外实测数据相结合的方法,利用SPSS2. 0数据分析软件,对阿拉尔土壤盐渍化的空间分布特征及影响因子进行了研究。结果表明:阿拉尔地区盐渍化表聚强烈,盐渍化类型以硫酸盐型为主,不同深度的土壤盐渍化特征不同,0～0. 2m、0. 6～0. 8m土壤盐渍化以中等盐渍化为主,1. 4～1. 6m以轻度盐渍土为主,整体轻度盐渍土面积不断增加;盐渍化与地下水特征关系密切,地下水矿化度 3g/L,对应盐渍化多为中度-重度盐渍化,地下水埋深1～3m,盐渍化多为中度-重度盐渍化。     

山东寿光北部地区土壤盐渍化特征与现状评价

为了解山东寿光北部地区土壤盐碱化现状及为工程建设、生态环境改良提供基础资料,通过野外采样和室内试验,分析了土壤盐碱化分布特征和类型,识别出盐分的主要形态。结果表明,研究区土壤含盐量总体不高,局部地段处于轻度至中度盐渍化程度;盐分含量北高南低,近似平行于海岸分布;土壤中阳离子以Na~+为主,阴离子主要为Cl~-和SO_4~(2-),盐分类型为氯盐渍土、亚氯盐渍土和亚硫酸盐渍土三类。     

天津滨海地区土壤剖面盐渍化特征及其影响因素

土壤盐渍化是由自然或人类活动引起的一种环境风险,对工农业生产具有重要影响。本次研究在天津滨海地区布置了6条具有代表性的土壤盐渍化剖面,选取其中4个剖面进行了为期两年的按月采样监测。研究发现,除了BHY6土壤剖面由于长年耕种,表现为平衡型土壤剖面形态之外,其余基本表现为底聚型土壤盐渍化剖面形态;从剖面中下部直到底部浅层地下水位附近,土壤中阳离子以Na+为主,阴离子以Cl-或Cl-+HCO-3为主,尤其在浅层地下水矿化度显著偏高(达盐水程度)的地区,土壤中Na+、Cl-所占比例具有绝对优势,具有滨海盐土的基本发生特征;气候因素、浅层地下水矿化度及埋深、表层土壤植被都是滨海地区土壤盐渍化的重要影响因素。表层土壤表现出春季积盐、夏季脱盐、秋冬季缓慢积盐的特征,浅层地下水矿化度越高、埋深越浅,其土壤剖面含盐量越高;果林地和长期耕种的土地可以降低土壤盐分的活性,有效抑制盐分的累积,降低滨海地区土壤盐渍化程度,保护和改良土壤。     

且末县土壤盐渍化分布特征及成因分析

以且末县土壤为研究对象,对该地区土壤盐渍化分布特征及成因进行了分析。研究结果表明:研究区盐渍土在平面上盐份主要富集在水位埋深较浅的车尔臣河中下游的沼泽-化学沉积平原区;在垂向上盐份富集在地表,随深度增大含盐量减小,并且所含盐类由表层以硫酸盐、亚硫酸盐为主,向深部逐步变为以氯盐为主;成因主要是且末绿洲区气候干旱,蒸降比大,地形封闭,盐源丰富、盐分表聚明显,加之灌溉措施及生产经营方式不够合理;预测车尔臣河中下游广大地区内土地盐渍化程度及范围将呈增强趋势,预计到2025年,研究区内盐渍化土地面积将会达到2 509.87 km~2,2030年将会达到2 966.56 km~2。     

干旱绿洲区包气带土壤盐分分布特征及运移机制——以新疆焉耆盆地为例

土壤盐渍化问题严重制约着我国干旱—半干旱区农业可持续高质量发展,了解包气带土壤盐分离子分布特征及垂向运移机制对科学防治土壤盐渍化具有重要意义。通过精细化采集新疆焉耆盆地2 m深度剖面土壤,测定样品机械组成和8种盐分离子含量,计算土壤颗粒分形维数,采用统计学方法分析包气带土壤盐分离子垂向分布特征,对包气带土壤质地与水盐运移间的关系进行探讨。结果表明,博湖剖面包气带土壤主要为非盐渍土,土壤盐分主要受开都河下游地下水水化学类型和矿化度控制,阴阳离子比值约为2∶5,盐分类型主要为Ca2+—HCO2-3和Na+—SO2-4型;焉耆剖面包气带土壤普遍为重度盐渍土,土壤盐分受到开都河下游地下水水化学类型和自身包气带盐分的综合影响,阴阳离子比值约为1∶2,盐分类型主要为Ca2+—SO2-4型和Na+—Cl-型。土壤分形维数和黏粒含量之间显著正相关,与砂粒含量显著负相关,包气带土壤盐分与分形维数间相关性不明显,主要受到土壤粒径组成及其所处深度等综合作用的影响。博湖包气带土壤质地由表层至深部逐渐变粗,盐分含量呈现出在0~80 cm深度的表层和125~200 cm的底部波动大,80~125 cm稳定的变化趋势,盐分离子主要聚集在约30 cm深度粉质黏壤土与粉质黏土层的交界处。土壤盐分运移大致可划分为交互作用段(0~80 cm)、平衡段(80~125 cm)和地下水扰动段(125~200 cm) 3个部分,蒸发作用影响深度约80 cm。焉耆包气带土壤质地由表层至深部逐渐变细,随深度的增加,盐分含量和波动程度均逐渐减小,盐分离子主要聚集在0~10 cm表土层。盐分运移大致可划分为盐分离子上升段(0~120 cm)和平衡段(120~200 cm)两个部分,蒸发作用影响深度约为120 cm。上细下粗型的包气带土壤质地组成是抑制土壤盐渍化较为理想的分布模式,对于焉耆剖面类型可先采取灌溉压盐,然后进行约40 cm深度的翻耕,博湖剖面类型可直接采取50 cm左右深度的深耕,一定程度上能够抑制盐渍化的发生。     

藏南扎西康矿集区土壤盐渍化空间分布及成因分析

旱—半干旱高寒地区土壤盐渍化,对区域农牧业发展及地质环境造成较大的影响。本文在西藏扎西康矿集区环境地质调查的基础上,通过对宿麦朗沟盐渍化3处土壤剖面系统采样分析,查明土壤盐分的空间分布及盐渍化成因。结果表明：相同层位土壤电导率与水溶性盐分总量之间呈正相关关系,0~80cm之间,土壤中盐分离子含量变化较大;80cm之下,土壤盐分含量趋于稳定;因子分析进一步揭示,研究区土壤盐分主要由氯离子、钠离子组成,两者之间相关性较强（R²=0.9592）;维美组地层以高硅、高钠为特征,三角洲及河流相的沉积环境及地下水活动等共同造成该区域土壤盐渍化。在此基础上,针对性地提出了降低地下水位、定期人工喷淋洗盐及施入有机肥料等方法是干旱区土壤盐渍化防治的有利措施。     

江苏沿海盐渍土盐渍化程度及其影响因素分析

盐渍土是江苏沿海地区开发建设需关注的地质环境问题之一。本文系统采集5 m以浅的土样,开展易溶盐试验,研究了江苏沿海盐渍土分布规律、盐渍化程度及影响因素。研究结果表明:全区盐渍土平行于海岸线分布;以中、弱盐渍土为主,强盐渍土零星分布。受沉积环境、气候、水文地质条件、人类活动等共同影响,盐渍化程度空间差异明显。平面上,盐渍化程度呈北强南弱、向海岸线方向延伸有逐渐增强的趋势,强盐渍土分布于连云港黏性土区,岩性、地下水矿化度为主导影响因素。垂向上,表层普遍积盐,连云港地区分带不明显,大丰和南通地区自地表而下可划分为三带,表层土蒸发积盐、中层盐动态变化、下层土饱水盐稳定,地下水位、土体结构为主导影响因素。随着沿海大开发的快速推进,为防止次生盐渍化问题,需关注地面沉降导致的地面高程损失诱发海水入侵加重表层土盐渍化,工程建设中可设置隔离层截断高矿化度地下水的毛细作用。     

西北地区黑河中游盐渍化地区土壤盐分特征

土壤盐渍化是黑河中游可持续发展面临的主要问题之一,有必要深入分析该区盐渍化土壤的盐分含量以及各可溶性离子的相关性。通过野外考察和GPS定点等手段,在甘肃张掖市高台县境内黑河两侧盐渍化土壤进行了采样。采样方式为人工坑探分层取样法,地表5 cm内取样,如土壤剖面层位变化时取样,层位不变或者层位厚度超过50 cm时,平均30 cm取一次样;待水位静止后,采取地下水样品。一共坑探15个剖面,共采取90个土壤样品和15个地下水样品。样品的盐分以及各可溶性离子含量的测试结果表明:区内表层土壤属于重度盐渍土,土壤中盐类主要为硫酸盐,其次为氯化物,盐分聚集层的厚度在20~30 cm之间;在各层中,含盐量与SO24-、K++Na+、Cl-、Mg2+相关性较强,SO42-、Cl-与K++Na+的相关性较强,但在深度为90~100 cm的土层中各种相关性都减弱;土壤垂直剖面上,颗粒越细的层位其盐分含量越大,颗粒越粗的层位其盐分含量越小,而且颗粒粗大的层位越厚其表层盐渍化程度越低,颗粒细小的层位越厚则表层盐渍化程度增高。     

渤海湾西岸滨海盐渍土的盐渍化特征分析

渤海湾西岸滨海盐渍土的盐渍化特征与滨海平原的地面高程、气候条件、盐渍土的理化性状、地下水的矿化度及人类活动等密切相关。就土盐渍化的程度而言,地面高程较高处的土高于地面高程较低处的土,上层土高于下层土。受蒸发和降水影响,地下水位以上土的盐渍化敏感深度为1 m左右。随着气候的变化,滨海盐渍土显现出春季蒸发,上层土积盐;夏季淋洗,土中盐分向下移动的盐渍化特征。随着深度的增加,土的含盐量逐渐减少,至地下水位附近出现轻微增长。从剖面上地表至地下水位间可划分为3个不同聚盐形态和含盐量的土盐渍化程度分区带,即土蒸发浓缩聚盐带、土盐化变动带和土饱水溶盐带;平面上向海岸线方向延伸,土逐渐由非盐渍土变为弱盐渍土、中盐渍土和强盐渍土,含盐量和盐渍化程度也越来越高。地下水位浅和地下水矿化度高,则上层土的盐渍化程度就愈高。     

焉耆盆地土壤盐分剖面特征及其与土壤颗粒组成的关系

为查明焉耆盆地土壤盐分剖面特征及其影响因素, 进行土壤样本含盐量及颗粒组成测试, 利用Spearman等级相关分析两者关系.结果表明: 土壤盐分剖面分为3种类型——均布型、表聚型和振荡型, 均布型剖面含盐量最低且分布均匀, 表聚型剖面盐分表聚特征最明显(表聚系数4.20), 振荡型剖面含盐量高且变异程度大(变异系数82.4%); 土样类型中粉质壤土最多(占70.8%), 颗粒组成中粉粒平均含量最高(57.1%); 均布型剖面盐分与粘粒含量相关程度最高(相关系数0.560), 为极显著正相关; 振荡型剖面盐分与砂粒含量相关程度最高(相关系数-0.639), 呈极显著负相关; 表聚型剖面盐分与颗粒组成无明显关系.结合各类剖面分布区域可知, 在砂粒含量与盐分含量较低的非盐渍化地带, 土壤盐分分布主要受粘粒含量影响; 砂粒含量与盐分含量较高的盐渍化地带, 土壤盐分分布主要受砂粒含量影响.      

Contribution of shallow groundwater rapid fluctuation to soil salinization under arid and semiarid climate

Rising saline shallow groundwater and associated soil salinization problems are widespread especially in arid and semiarid areas. There have been numerous studies on groundwater-associated salinity, but more information is required on the effects of groundwater frequent and high fluctuations on soil salinization. In the present study, laboratory experiments and numerical simulations using HYDRUS-1D model were carried out for this purpose. The experimental and modeling results showed that groundwater fluctuation caused not only the accumulation of more salt in the soil profile compared to stable groundwater, but also an enhancement of the mechanism. Water table fluctuation induced a much greater spreading of the bromide (Br) tracer within the column than the constant water table. The Br content was on average five orders of magnitude greater under a fluctuating water table than under a constant one. Further, the numerical simulations showed that an increase in the groundwater fluctuation frequency brought about an increase in soil surface salinization under the same evaporation boundary conditions. Additional simulations with HYDRUS-1D were used to study the effects of various management strategies on soil salinization induced by shallow groundwater. Hence, by reducing the evaporation rate through the application of surface mulching, a significant reduction of salt concentration at the soil surface was observed. Moreover, frequent irrigations with small quantities were effective to reduce soil surface salt accumulation induced by saline shallow groundwater.     

黄河三角洲浅层地下水盐分来源及咸化过程研究

黄河三角洲地下水咸化已成为区域最突出的生态环境问题之一。识别地下水补给及盐分来源是有效控制和改善地下水咸化问题的关键。本研究采集了研究区浅层地下水、地表水和海水等不同类型水样,利用离子比、Piper三线图、吉布斯图等方法对八大离子浓度、δD和δ¹⁸O 组成、Br和Sr 浓度等进行地下水补给研究与盐分来源辨析。结果表明:(1)黄河三角洲浅层地下水以总溶解性固体(TDS)为338 g/L的咸水为主,地下水水化学类型较为单一,主要为Cl-Na型。(2)三角洲区域地下水以大气降水补给为主,并且在补给过程中经历了不同程度的蒸发作用的影响,黄河现行流路区域地下水主要来源于河水侧渗补给,但浅层地下水含水层水平渗透性较差限制了黄河侧渗补给范围。(3)海洋是黄河三角洲浅层地下水盐分的主要来源,黄河现行流路区域及近岸地下水盐分来源于海水混合,三角洲北部刁口河等古河道区域地下水盐分主要来源于海相蒸发盐淋滤溶解。     

银川平原主要水环境问题及其对策

基于野外调查、取样分析以及遥感影像等,介绍了银川平原水文地质条件及水资源利用概况,探讨了土壤盐渍化、湖泊湿地萎缩、地下水盐化、地下水超采以及土地荒漠化等水环境问题及其演化成因。结果表明：银川平原地下水主要接受渠系渗漏及灌溉入渗、大气降水入渗、平原周边地下侧向径流、洪水散失、黄河水等补给,地下水排泄方式主要是排水沟排泄、蒸发和人工开采等,大部分地区潜水埋深在3 m以内;地表水主要来源于黄河引水,水资源利用效率不高;土壤盐渍化总面积8.17×104hm2,呈逐年缩减的趋势,主要分布于银川平原北部,平原南部仅分布在邵岗东部、灵武东部秦渠和东干渠等;湖泊湿地总体呈逐渐减少趋势,主要分布在银川平原北部,永宁以北、平罗以南区域比较集中,滩涂沿黄河两岸分布;潜水总含盐量自西向东、自南向北不断增大;银川和石嘴山深层地下水超采严重,地下水降落漏斗面积已超过500 km2;沙漠化土地分布在银川平原的东西两侧;土壤盐渍化及地下水盐化主要由潜水位埋深过浅,蒸发强烈造成的。最后,提出了防治上述水环境问题的对策：进一步加强水资源管理以及地表水与地下水联合调配;提高农业水资源利用效率;完善田间工程配套,实现渠道防渗管道化;改进田间灌溉技术;严格污水排放,积极开展污水净化处理,实行污水资源化;加强对水土环境质量的系统监测。     

Dynamics of the soil water and solute in the sodic saline soil in the Songnen Plain,China

According to the field experiment in the sodic saline soil region in the Songnen Plain, the dynamics of the soil water and solute affected by the shallow groundwater were explored during the growing season in 2004. The results presented that, influenced by the strongly evaporative demand, the soil water tended to transport to the upper soil layer with salt. The layered soil water balance model (LSWB model) revealed that the ratio of the water exchange between the groundwater and upper layer of the soil was 11.7:1. The groundwater discharge was 53.86 mm, but the groundwater recharge from the upper layer of soil was only 5.04 mm from 11 July to 06 September, which indicated that the groundwater could discharge to upper layer of soil and influence the soil salinization through capillary rise. The observed values of the salt content from July to mid-October presented that the soil solute was more changeable influenced by the climatic condition at 30 cm depth. As the field saturated hydraulic conductivity was low, the salts mainly accumulated in about 50–70 cm depth soil layer and hardly leached into deeper soil layer. Furthermore, the salt content was mainly controlled by the groundwater in the subsoil below 100 cm depth, the salt content decreased with the groundwater level receding. As influenced by the shallow groundwater and freeze-thaw action, further studies should be performed on the mechanism of soil salinization in the sodic saline soil region in the Songnen Plain of China.     

Analysis on the Salt Content Characteristics of Southern Saline-Alkali Soil in Datong Basin and Its Causes

This paper studies the southern part of Datong Basin and investigates, in combination with a survey on the soil properties, the salt content characteristics of the soil in the region using relevant analysis methods. The results showed that the soil salinization type of the soil in the study area is soda saline-alkaline soil, and the salt content of the profile soil tends to assemble in the soil surface. As the overall salt content is low, it is classified as moderately saline soil. However, being highly alkaline, it thus basically belongs to the moderate-to-severe level; a significant positive correlation is found between total salt quantity and exchange sodium and degree of alkalization. Exchange sodium is a factor that determines the size of alkalization degree and it also indirectly affects the pH value; special climate, topography and parent material, groundwater and soil properties, and tillage management of the region explain the formation of the large area of saline-alkali soil. This study will provide an important theoretical basis for the sustainable use of soil resources in the southern saline-alkali soil in Datong Basin     

Distribution and evolution features of salinized soil in Hebei Plain

In order to study the distribution and evolution features of saline soil, the correlations between the groundwater depth, salinity and salinization of soil are examined through analyzing the hydrometeorological data and distribution maps of saline soil, groundwater depth and salinity in 1957 and 2005. The results show that the area of salinization has generally decreased. The area of salinization decreases with the increasing groundwater depth, and the dynamic evolution characteristics appeared between the groundwater depth and area of salinization. The area of heavy salinization is greatest when the groundwater salinity is > 5 g/L, the area of moderate salinization is greatest when the groundwater salinity is between 2-5 g/L, the area of light salinization is greatest when the groundwater salinity is 1-2 g/L and the area of non-salinization is greatest when the groundwater salinity is <1 g/L. The area of heavy salinization was characterized with groundwater depth <2.5 m and salinity >1.8 g/L. The area of non-salinization was characterized with groundwater depth >4.0 m and salinity 0.2-1.5 g/L.     

银川平原土壤盐渍化与植被发育和地下水埋深关系

土壤盐渍化是制约银川平原内部植被生长最主要的生态环境地质问题,也是影响区域农业生产的第一障碍性问题。基于遥感数据,结合表层土壤含盐量及地下水位观测资料,对银川平原土壤盐渍化与植被和地下水的关系进行了定量研究。结果表明：随着表层土壤含盐量的增大,NDVI(归一化植被指数)逐渐减小,植被发育较好的区域土壤含盐量均小于3 g/kg;植被主要生长在没有盐渍化或轻微盐渍化的地区,在中度和重度盐渍化地区几乎没有植被发育;在枯水季节,研究区土壤盐渍化最严重的地下水位埋深为1.5 m,而土壤盐渍化较为严重的地下水位埋深范围为1~3 m。