Ecological-evolutionary analysis of lithium content in soils

Abstract

The point is that investigation of geochemistry and behavior of Lithium in Ukraine’s soils is been rather exceptional. We have analyzed the content of Lithium in soils: modern and buried under the ramparts of various ages. The research territory includes Prut-Dniester and Prut-Siret interfluvial. Most often there are Phaeozems (Luvic Phaeozem, or Mollic Gleysol or Eutric Gleysol) and Chernozems (Luvic Chernozem or Chernic Chernozem). Buried soils are located directly near the modern background soils, so the differences between them are the result of evolution of the background soils during burial (the screening) after the construction of ramparts. On the Podvirna site current landscapes are wood and meadow-steppe; in the past, subboreal stage, were probably closer to the steppe; buried soil – Chernozem typical with a little profile, in the modern of soil structure prevails Luvic Phaeozem. The sites Ridkivtsi and Grushivka are characterized forest landscapes and in the past on those areas dominated wood-meadow landscapes. At present prevailing types of soils are Phaeozems or Gleysol. Soil samples have taken for the genetic horizons. After drying and preparing of soils in them had performed analytical determination of total content (Nitrate extract, followed by evaporation of hydrogen peroxide) of Lithium and its mobile forms (ammonium acetate-extract with pH = 4,8). The results of analyzes had processed by using statistical and mathematical testing based on the program «Statistica 6.0». Our obtained results are indicating background of total Lithium content, which ranges from 8,70 to 33,5 mg∙kg^-1 and its average amount was 22,3±6,01 mg∙kg^-1; amplitude quantity of Lithium mobile forms is between 0,20 to 2,60 mg∙kg^-1, with an average content of 0,60±0,57 mg∙kg^-1. The mean of total Lithium content of all soils with buried soils in particular are decreased from Podvirna site (27,4 mg∙kg^-1) to the site Ridkivtsi (22,8 and 26,3 mg∙kg^-1, accordingly) and site Grushivka (20,0 and 19,1 mg∙kg^-1, accordingly), while the number of mobile forms changed significantly from substantial Podvirne hospital (1,43 mg∙kg^-1) to the hospital Grushivka (0,83 and 0,91 mg∙kg^-1, respectively) and hospital Ridkivtsi (0,44 and 0,79 mg∙kg^-1, appropriately). In the majority of background soils we had discovered humus-eluvial-illuvial redistribution, sometimes - eluvial-illuvial redistribution. It is important to know that we had not observed high Lithium content in the parent rock of soils (except for two sections of the site Ridkivtsi with discussion rather recognition of the parent rock of the profile). This is demonstrating the determining influence of pedogenesis on the redistribution of chemical elements in the of soils. Actually, Lithium has often accumulated in the upper humus horizons (as a result of the impact of organic matter and of soil biota as a whole) or in the horizons of clay accumulation. To crown it all pedogenesis fundamentally has changing features of the vertical distribution of Lithium content. Concerning future research is necessity of application of isotopic analysis to identify the characteristics of different ages soils.