CARBONATE CONTENT OF MEADOW-ALLUVIAL AND TAKYR-LIKE MEADOW SOILS UNDER THE INFLUENCE OF DESERTIFICATION

Аннотация

The article presents information on the carbonate content and calcium and magnesium carbonates in the carbonate content of the soils distributed on the right and left banks of the Lower Amudarya. Key words: meadow-alluvial and takyr-like meadow, common carbonates, calcium carbonate, magnesium carbonate, dolomite. Introduction: As a result of the negative impact of human activity, significant changes in the environment are observed in many regions of our planet. One of them is global climate change, various natural disasters, which are felt in all latitudes of the planet. As a result, the areas covered with natural forests are decreasing, various negative processes in the atmosphere, water and lithosphere are increasing. Determination of carbonates in soils is very important, where high amounts of calcium and magnesium carbonates increase the alkalinity of the soil reaction (pH) and significantly reduce the mobility of nutrients, in which the amount of mobile nutrients that can be absorbed by plants in the soil can fall to a deficit level, and after the depletion of nutrients in the soil, has a negative effect on the growth and development of plants. Research object and methods: Old and newly irrigated meadow-alluvial and takyr-like meadow soils, widespread in Chimboy and Shumanay districts on the right and left banks of the Lower Amudarya, are the object of research. Genetic-geographical, lithological-geomorphological, comparative, profile and chemical-analytical methods were used in the research. Soil research is carried out according to "Manual for conducting soil research and drawing up soil maps for the state land cadastre" [1], chemical analysis of soil samples are carried out according to "Agrokhimicheskie metody issledovaniya pochv i 22 INNOVATIVE RESEARCH IN SCIENCE International scientific-online conference rasteniy", UzPITI [2], "Rukovodstvo po khimicheskomu analizu pochv" and the manuals of E.V. Arinushkina [3]. The obtained results and their analysis: The acidimetric method was used to determine the amount of carbonate in the soils distributed on the right and left banks of the Lower Amudarya. Determination of carbon content of soils is based on their decomposition with 0.02 N hydrochloric acid. An increase in the amount of CO in the soil solution causes an increase in 2 the solubility of CaCO , and calcium carbonate partially turns into bicarbonate. 3 As a result of the formation of HCO ions in the soil, the alkalinity of the soil 3 increases and causes a sharp increase in the pH indicator, that is, the formation of soda (NaCO ) [4]. 3 Table 1. The amount of carbonates in the soils on the right and left banks of the Lower Amudarya, %. Layer depth, cm CO CaCO MgCO 2 3 3 % 1. Chimboy district B-2 Irrigated takyr-like meadow. The modern delta of Amudarya, consisting of alluvial deposits 0-28 9,8 8,40 1,241 28-49 10,0 8,60 1,219 49-70 10,1 7,70 1,095 70-93 8,1 6,50 1,584 93-112 8,6 7,10 0,292 112-160 9,3 7,40 1,022 2. Chimboy district B-4 Irrigated takyr-like meadow. The modern delta of Amudarya, consisting of alluvial deposits 0-24 8,3 7,70 0,584 24-49 8,5 7,50 0,949 49-61 10,3 8,90 1,387 61-75 10,7 9,70 0,949 75-100 10,1 9,20 0,876 100-131 8,1 7,50 0,511 131-200 7,6 7,40 0,292 3. Shumanay district Sh-5 Irrigated meadow-alluvial. Delta of Amudarya formed from layered alluvial deposits 0-43 9,8 7,98 0,365 43-65 10,4 8,12 1,022 23 INNOVATIVE RESEARCH IN SCIENCE International scientific-online conference 65-87 9,7 7,40 0,730 87-107 10,7 7,70 1,095 107-131 9,5 7,00 1,095 131-170 10,9 9,10 0,876 4. Shumanay district Sh-1 Irrigated meadow-alluvial. Delta of Amudarya formed from layered alluvial deposits 0-34 8,9 8,26 0,584 34-44 9,1 8,12 0,511 44-66 9,5 7,98 0,584 66-84 9,2 8,68 0,146 84-105 10,6 8,82 0,876 105-150 10,5 9,1 0,438 As a result of our research, we can see that the amount of carbonate fluctuated between 7% and 11% in both districts (Table 1). It was observed that the amount of carbonate is less in the upper layers of the sections, and it is washed downwards. It was found that it fluctuated between 7.6% and 10.7% in the old irrigated barren meadow soils. We can see that in our determined soils, CaCO occupies the most part, that is, between 7.1% and 9.7%, and MgCO 3 3 fluctuates between 0.292% and 1.584%. In newly irrigated meadow-alluvial soils, carbonate content varied from 8.9% to 10.9%, CaCO content varied from 7.0% to 9.1%, and MgCO from 3 3 0.146%. We can see that it fluctuated between 1.095%. Conclusion: In the meadow-alluvial and takyr-like meadow soils distributed on the right and left banks of the Lower Amudarya, the amount of carbonates is weakly carbonated, the mostly CaCO is found, equal to 80-95% of the total 3 amount. The remaining part is mainly MgCO , which is found in soils in the form 3 of dolomite. Reference: 1. R.K. Kuziev and others. Guide to conducting soil surveys and drawing up soil maps for the maintenance of the state land cadastre. Tashkent, 2013. 52 p. 2. UzPITI.