Effect of moisture variation on sulfate concentration in a buck solonetz soil

Abstract

Sulfate concentration in the equilibrium solutions of a black solonetz soil was different at each moisture content. In the sub‐surface horizons a decrease in soil moisture up to about 35 percent resulted in a gradual increase of sulfate concentration. However, with further decrease in moisture the sulfate concentration increased abruptly. Variation of sulfate concentration appears to alter significantly certain cation ratios in the equilibrium solutions.     

宁夏银北地区龟裂碱土盐分特征研究

为探明龟裂碱土的基本盐分状况,并建立在滴灌利用条件下基于电导率的土壤主要盐分性质的预测模型,本文在野外调查、取样和化学分析的基础上,利用经典统计分析方法,对我国宁夏银北地区龟裂碱土盐分特征进行了研究.结果表明,龟裂碱土剖面内盐分含量总体呈现“表聚”现象,主要盐分离子含量随深度增加逐渐降低.Cl-和Na+是该土壤中最主要的阴阳离子,且在上层土壤中表现尤为突出,HCO3+含量在100 cm以下的土层中逐渐增加.表层土壤钠吸附比(SAR)值较大,均在15(mmol/L)0.5以上,pH值在8.5～10之间.Na+与Cl-的相关性最强,相关性系数为0.902 (P＜0.01),Na+与SO42-、HCO3-的相关性次之.土壤饱和浸提液电导率(ECe)和Cl-、Na+、可溶性总盐(TSS)含量及SAR值显著正相关(P＜0.01).土壤Cl-、Na+、TSS含量及SAR可由自变量为ECe的数学回归方程来表达,且预测精度可靠,可快速、经济地模拟和预测该地区土壤Cl-、Na+、TSS含量及SAR值,为本区域滴灌精准改良利用条件下龟裂碱土的盐渍化状况评价提供参考.     

吉林省大安市苏打碱土含盐量与电导率的关系

分别测定了吉林省大安市苏打碱土含盐量与电导率以及地下水含盐量与电导率,分析了含盐量与电导率的关系。结果表明,土壤含盐量与电导率、地下水含盐量与电导率之间具有良好的线性相关性,土壤浸出液电导率(y)与土壤含盐量(x)之间的回归方程为:y=0.201 0.092x(r=0.991,n=50,p<0.0001);地下水电导率(y)与含盐量(x)之间的回归方程为:y=-0.393 1.523x(r=0.997,n=18,p<0.0001)。利用方程计算的土壤含盐量与实测值之间符合较好,相对误差大多在7%以下;根据电导率计算的地下水含盐量与实际测量值之间的相对误差一般在5%以下。说明在数据统计分析基础上建立的这两个经验公式适用性较好,可以用于该区苏打碱土土壤及地下水电导率与含盐量之间的换算。     

吉林省大安市苏打碱土碱化参数与特征

对大安市苏打碱土的主要碱化特征参数：土壤碱化度（ESP）、总碱度、pH等指标进行了测试分析。分析了该类型土壤碱化特征及其垂直分布态势。结果表明，土壤可溶性离子组成以Na^1NHCO3^-离子为主，两者占可溶性阳离子、阴离子总量的比例均在70％～80％以上，NaHCO3是造成该土壤碱化和性质恶化的主要因素。在20～80cm内出现一个明显的碱化层，该层ESP在25％～30％以上，pH〉10．3，在此范围之外，土壤碱化特征均有减弱趋势。土壤ESP与土壤禽盐量、总碱度和pH均具有相关性，ESP随土壤含盐量、总碱度的增大而增大。     

On the Fundamental Causes of High Environmental Alkalinity (pH ≥ 9): An Assessment of Its Drivers and Global Distribution

Very alkaline environments exceeding calcite buffering are globally rare but conspicuous in many sedimentary plains of the World. While the deleterious effects of high alkalinity on soils are well understood, less agreement exists on its causes. We revise these causes to understand these exceptional environments and explain the pervasiveness of calcite buffering elsewhere. We argue that the injection of respired CO₂ into stagnant hydrological systems subject to evaporative discharge is the key context for high alkalinization. The evolution of evaporites in nature reaches highly alkaline stages only when excess of (bi)carbonate with respect to divalent cations occurs. In most dry landscapes, evaporating groundwater solutions lose this condition as respired inorganic carbon (recharge zone supply) equilibrates with divalent cations from rocks (whole hydro‐trajectory supply). Groundwater in stagnant landscapes avoids this limitation owing to short/shallow trajectories sustaining (bi)carbonate excess until evaporative discharge zones are reached. Flat sedimentary landscapes that are (i) wet enough to develop stagnation and have shallow water tables but (ii) sufficiently dry to expose them to evaporative concentration should host very alkaline soils. This is confirmed with >9,000 soil profiles from the global WISE database, which shows that profiles with pH ≥ 9 in the top meter are 2·7% globally but 18% in areas with low slope (<0·05%, 25‐km radius, SRTM digital elevation model (SRTM DEM)) and semiarid–subhumid climate (annual precipitation to potential evapotranspiration ratio = 0·2–1, CRU database). Understanding how climate and vegetation change as well as irrigation practices influence hydrological stagnation and evaporative concentration may provide the key to manage very alkaline environments. Copyright © 2017 John Wiley & Sons, Ltd.     

苏打碱化土壤碱化参数的干湿季节动态变化

选取吉林省西部典型苏打碱化土壤,分别于干季6月、湿季8月和干季10月进行取样分析,测定计算土壤剖面各碱化参数(pH、SAR、SSP、SDR、总碱度、RSC和ESP),分析在气候干湿季节变化过程中各碱化参数的动态变化特征。研究结果表明,随着气候"干季-湿季-干季"的变化过程中,苏打碱化土壤各碱化参数也呈现较规律变化,其总体特征是各碱化参数在由干季向湿季(6月—8月)表现为升高趋势;而在湿季向干季(8月—10月)则表现为降低趋势。从变化幅度看,以表层土壤(0～20cm)变化更为显著。干季强烈蒸发作用导致地表积盐、湿季地下水位埋藏浅以及苏打碱化土壤通透性能差是造成湿季各碱化参数增大的主要原因。     

东亚和邻近地区受盐影响土壤的性质及盐化危险

Asia is the largest distribution area of salt-affected soils in the world,Very few countries in Asia could escape from hazard of salinization.This paper deals with various salt-affected soils spreading in East Asia and its neighboring regions (including China,Japan,Kampuchea,Democratic Peolpe‘s Republic of Kores,Republic of Korea,Laos,Mongolia,Burma,Thailand and Vietnam),Principles of occurrence of salinization,and features of salt-affected soils in these regions have been studied in the present paper,Based on studies on types,features and distribution patterns of salt-affected soils.a salt-affected soil map of East Asia and its neighboring regions has been complied.Mechanism and manifestation of the salinization hazard on the regional agriculture and ecological environment,measures of preventing salinization hazard and exploiting salt-affected soils in these regions are also discussed.     

滴灌枸杞对龟裂碱土几种酶活性的改良效应

在盐碱地改良利用过程中,有必要研究土壤酶活性变化,以评价土壤环境质量的改善。龟裂碱土重度盐碱荒地主要分布在我国西北旱区,该土壤碱化度高,结构差,导水率极低。2009年,采用滴头下设置沙穴的方式滴灌种植枸杞,开垦利用该盐碱荒地。2011年枸杞生长季末,在不同种植年限地块土壤剖面上网格状密集取土,进行土壤脲酶、碱性磷酸酶和蔗糖酶活性的测定。结果表明,未种植土壤3种酶活性极低;滴灌种植之后,随着根区土壤水盐特性和养分状况的改善,土壤酶活性显著增加。就整个土壤剖面而言,土壤酶活性自根区向四周逐渐降低,表现出较大的空间变异性。相关性和通径分析结果显示,土壤p H始终是影响该土壤酶活性的主要因子,且在p H7.38~10.00的范围内,3种酶活性随土壤p H的增大呈指数式减小(p0.01)。总之,滴灌种植枸杞之后,龟裂碱土重度盐碱荒地土壤生物学性质得到显著改善。     

龟裂碱土地下水年际动态变化特征研究

旨在为龟裂碱土改良利用水盐调控提供理论依据,本研究对龟裂碱土用绳测法测地下水埋深、电导率仪测定矿化度、多参数测试仪测定pH值和滴定法测定盐分离子,对比分析龟裂碱土地下水埋深、矿化度、pH值和盐分离子年际变化规律。结果表明：地下水埋深和矿化度横向变化较大,变异系数分别为22.2%和38.9%,盐分离子Na⁺、Cl^-和HCO₃^-横向变异较大,Ca²⁺和K⁺横向变异较小;地下水盐分离子主要以Na⁺、Cl^–、SO₄^2-和 HCO₃^-为主;地下水埋深逐年变浅,pH值、矿化度逐年变小。本研究结果为龟裂碱土改良利用水盐调控提供依据,以及对干旱地区的环境保护和农业灌溉具有重要的科学价值。