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首页> 外文期刊>Catena: An Interdisciplinary Journal of Soil Science Hydrology-Geomorphology Focusing on Geoecology and Landscape Evolution >Soils, surficial geology, and geomicrobiology of saline-sodic wetlands, North Platte River Valley, Nebraska, USA.
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Soils, surficial geology, and geomicrobiology of saline-sodic wetlands, North Platte River Valley, Nebraska, USA.

机译：美国内布拉斯加州北普拉特河谷的盐碱湿地的土壤，表面地质和地球微生物学。

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摘要

Saline-sodic wetlands along a 200-km stretch of the North Platte River Valley in western Nebraska, USA lie within an important agricultural region, but their processes, salt mineralogy, and geomicrobiology have not previously been investigated. Putative anthropogenic salinization has long been a concern, yet early historical accounts of widespread surface salts in the area have never been applied as comparative standards. Surface salts in the area originate from soil capillarity and surface evaporation. Thenardite (Na2SO4) and/or mirabilite (NaSO4.10 H2O) dominate, depending on ambient conditions. Bloedite (Na2Mg[SO4]2.4[H2O]), halite (NaCl), burkeite (Na6CO3[SO4]2), and calcite (CaCO3) are minor constituents. Historical accounts indicate that salts accumulated naturally long before Euramerican settlement, apparently as a result of rock-water interaction in nearby volcaniclastic sediments of the Brule Formation. Ephemeral to permanent water-holding basins in the wetlands contain Na+-rich waters that vary widely in electrical conductivity (as high as 159 mS/cm) and in ionic composition, but local spring waters are extremely dilute. Basin floors exhibit a unique type of microrelief, which appears to form by the filling of microlows with water and the dispersal of soil material therein by Na+, followed by dewatering and collapse of the soil with drying. Illite dominates basin surface soils, but smectite dominates at depth; high soil pH, available K+, and frequent wetting-drying cycles in the wetlands suggest that in-situ illitization may have occurred. Soil crusts and vesicular surface horizons are common as are upward increases in electrical conductivity. The activity of sulfate-reducing microbes forms prominent near-surface horizons of sulfate reduction in saturated soils, which retract or disappear entirely during dry episodes. Saline-sodic wetland soils in the study area change on daily to seasonal scales. Cycles of surface salt development, microbial activity, and microrelief genesis are all controlled by regular wetting-drying cycles and the interaction of ponded surface waters and shallow groundwaters. Relatively unique aspects of microbial ecology and surface processes make the soils important as "geomicrobial reactors" wherein important parts of hydrological and geochemical cycles occur..
机译：位于美国内布拉斯加州西部北部普拉特河谷200公里长的盐碱湿地位于重要的农业地区，但以前并未对其过程，盐矿物学和地球微生物学进行过调查。长期以来，人们一直认为可能的人为盐渍化问题，但是该地区广泛存在的表面盐的早期历史记载从未用作比较标准。该地区的表面盐分源自土壤毛细作用和表面蒸发。取决于环境条件，芒硝（Na2SO4）和/或芒硝（NaSO4.10 H2O）占主导。硼锌矿（Na2Mg [SO4] 2.4 [H2O]），岩盐（NaCl），钠钙石（Na6CO3 [SO4] 2）和方解石（CaCO3）是次要成分。历史记载表明，盐很自然地在欧美沉积之前就自然积累，这显然是由于附近布鲁尔组火山碎屑沉积物中的岩水相互作用所致。湿地的临时性到永久性持水盆地都含有富含Na +的水，它们的电导率（高达159 mS / cm）和离子组成差异很大，但是当地的泉水非常稀。盆地地面表现出一种独特的微浮雕形式，这种微浮雕形式似乎是通过在微凹处充水，然后用Na +分散土壤中的物质，然后通过干燥使土壤脱水和塌陷而形成的。伊利石在盆地表层土壤中占主导地位，而蒙脱石在深度上占优势。较高的土壤pH值，可用的K +以及湿地中频繁的干湿循环表明，可能已经发生了原地非法化。地壳和水泡表面层很普遍，电导率也随之增加。减少硫酸盐的微生物的活性在饱和土壤中形成了明显的硫酸盐减少的近地表层，在干旱时期会完全消失或消失。研究区的盐碱湿地土壤每天都在按季节变化。地表盐分发育，微生物活性和微浮雕成因的周期都由规则的干湿循环以及池下地表水和浅层地下水的相互作用来控制。微生物生态学和地表过程的相对独特方面使土壤成为重要的“地质微生物反应器”，其中发生了水文和地球化学循环的重要部分。

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