Abstract

The aim of this study is to present data on the salinity status of soils, sediments, and groundwater on irrigated rice fields of the Karkinit Lowland in Krasnoperekopskii district of Crimea in 2015–2018, 2–5 years after the irrigation stopped. Most of solonetzic microcatenas were transformed into rice paddies and irrigated by flooding during half a century; as a result, the soils were leached from soluble salts to a depth of 3–3.5 m. In 2015–2018, the groundwater table dropped below the critical level. Since 2017, a depression cone of the groundwater table has been formed at the seashore. This area is under the impact of seawater head of up to 0.8–1.1 m. The occurrence frequency of horizons with clusters of fine-grained gypsum crystals has increased in the vadose zone, and slight salinity has restored in sediments of the depression cone at a depth of 3.5–4.5 m. In rice paddies elevated by less than 2 m above seas level, the contents of soluble salts exceeded the low limit of slight salinity in the middle and deep parts of soil profiles on the fifth year after the cessation of irrigation. The maximum of soluble salts in the profile is accompanied by the appearance of calcium and magnesium chlorides in pore solutions and by the accumulation of fine gypsum grains (farinaceous gypsum).

中文翻译：

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灌溉停止后Karkinit低地稻田土壤和沉积物盐分的五年长期变化

摘要

这项研究的目的是提供在灌溉停止2至5年后的克里米亚Krasnoperekopskii区Karkinit低地的灌溉稻田中土壤，沉积物和地下水盐分状况的数据，时间为2015年至2018年。在半个世纪的时间里，大多数solonetzic微catenas被转化为稻田并通过洪水灌溉。结果，土壤从可溶性盐中浸出到3-3.5 m的深度。2015-2018年，地下水位下降到临界水平以下。自2017年以来，在海边形成了一个地下水位下降锥。该区域受到高达0.8–1.1 m的海水水头的影响。在渗流区，含细粒石膏晶体簇的层位出现频率增加，在3.5-4.5 m深度的凹陷锥沉积物中已恢复了轻微的盐度。在海拔高于2 m的稻田中，停止灌溉后的第五年，土壤剖面中部和深部的可溶性盐含量超过了轻微盐度的下限。剖面中可溶性盐的最大含量伴随着孔隙溶液中氯化钙和氯化镁的出现以及细石膏颗粒（钙质石膏）的积累。