Abstract

The characteristics of climatic, lithological and geomorphological conditions of formation of sandy soils of Transbaikalia (Barguzin basin) is given. It has been established that the main soil-forming processes are cryo- and light-humus, accumulative-carbonate and pale-metamorphic. In the soils of deposits, the processes of stratification and abrasion are expressed. Moving sands are not affected by soil formation, but with partial fixation of herbaceous and/or shrub vegetation on them, embryonic underdeveloped soils (layered-eolian, humus psammozems) begin to develop. For the first time, the results of the material composition of the rocks of the Angara-Vitim batholith, soil-forming sand, as well as the composition of minerals of fractions <1.1–5 and >5 µm of cryohumus and light humus soils are presented. It has been determined that the regional features of soil-forming sands are carbonation, alkalinity, and polymineral content, which is inherited from calc-alkaline rocks. The sandy and silty soil fractions have a similar mineralogical composition, which are characterized by a high content of plagioclases and K-feldspars and a low content of quartz. The composition of the silty fraction consists of a mixed-layer phase of illite-smectites interbedded with single chlorite packets, di-trioctadridic illite, ferruginous chlorite, and kaolinite. Modern soil formation is characterized by a low degree of chemical weathering (CWC, CWI, and GM) and weak profile differentiation. A feature of the material composition of sandy soils is an increased content of potassium and sodium. According to the values of total alkalinity, the studied soils are highly alkaline soils. There is a clearly pronounced division of the soil profile according to biological activity. It was revealed that during arable use, sandy soils are potential centers of desertification: in the studied area, all arable lands and fallows located on them are deflated to varying degrees. At the same time, it was found that more than 70% belong to very strongly deflated and strongly deflated types. In such areas, humus soil layers are blown out and carbonate horizons and even soil-forming sands are exposed. The exposed middle horizons and sands do not possess elements of effective fertility. The yield of agricultural crops on such arable lands is very low, the process of natural restoration of vegetation cover on fallow lands is extremely difficult, and deflation ulcers practically do not overgrow. The inhibition of the processes of restoration of natural cenoses is largely due to the alkalinity and carbonation of soil-forming sands.

中文翻译：

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外贝加尔新生代深层沙子和沙土的矿物学和物质组成的特点

摘要

给出了外贝加尔地区（巴尔古津盆地）沙土形成的气候、岩性和地貌条件特征。现已确定，主要的成土过程是低温腐殖质、轻质腐殖质、累积碳酸盐和浅变质作用。在沉积物土壤中，表现出分层和磨损过程。流动的沙子不受土壤形成的影响，但随着草本和/或灌木植被部分固定在其上，胚胎发育不良的土壤（层状风成土、腐殖质砂钙土）开始发育。首次对 Angara-Vitim 基岩、成土沙的岩石物质成分，以及冷腐殖质和轻质腐殖土的 <1.1–5 和 >5 µm 矿物成分的结果进行了研究。呈现。已确定成土砂的区域特征是碳化性、碱度和多矿物质含量，这是从钙碱性岩石遗传而来的。沙质和粉质土壤部分具有相似的矿物成分，其特点是斜长石和钾长石含量高，石英含量低。粉质部分的成分由伊利石-蒙脱石与单绿泥石包、双三十八伊利石、铁绿泥石和高岭石互层的混合层相组成。现代土壤形成的特点是低程度的化学风化（CWC、CWI 和 GM）和弱的剖面分化。沙土物质组成的一个特点是钾和钠的含量增加。根据总碱度值，研究土壤为强碱性土壤。根据生物活动，土壤剖面有明显的划分。研究表明，在耕地利用过程中，沙质土壤是潜在的荒漠化中心：在研究区，所有耕地及其上的休耕地都出现了不同程度的萎缩。同时发现70%以上属于极强瘪和强瘪类型。在这些地区，腐殖土层被吹走，碳酸盐层甚至成土沙都暴露出来。裸露的中层和沙子不具备有效肥力的元素。这些耕地上的农作物产量很低，休耕地上植被自然恢复的过程极其困难，通货紧缩溃疡实际上不会过度生长。自然生态恢复过程的抑制很大程度上是由于成土沙的碱度和碳化作用造成的。