Jour of adv research in dynamical & control systems, vol. 12, special issue-06, 2020
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- Soil cover of the aral sea region and change of soil properties under the influence of desertification
- Introduction
- Materials And Methods
- Experimental Results
- Table № 1.
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Jour of adv research in dynamical & control systems, vol. 12, special issue-06, 2020
620
DOI: 10.5373/JARDCS/V12SP6/SP20201072 *Corresponding Author : Bakhtiyor RamazonovichRamazonov Article History: Received: Mar 24, 2020, Accepted: June 27, 2020 Soil cover of the aral sea region and change of soil properties under the influence of desertification (on the example of soils of the karakalpakstan region) 1 Bakhtiyor RamazonovichRamazonov 1 Doctor of Philosophy in Biological Sciences (PhD), Chirchik State Pedagogical Institute of the Tashkent Region, Uzbekistan Abstract: This article summarizes information about changes in natural and anthropogenic desertification processes and the patterns of their manifestation in the Aral Sea region. In connection with the intensification of desertification, the arid-zonal factor began to play a decisive role in soil-forming processes—the rapid transition of hydromorphic soils to automorphic desert ones. It was revealed that with a sharp change in climate and the intensification of the desertification process in the main part of the Aral Sea territory, hydromorphic conditions disappeared and the landscapes acquired a desert character, the soil cover reached a typically desert stage of development, its biogeocenoses disappeared, and tugai vegetation also dried out. And also, this article is about the characterization of the soil cover of the Aral Sea region Desert-sandy soils, gray-brown soils, takirs and takyr soils are widespread in the region. We are also talking about the specific conditions of soil formation prevailing on the dried bottom of the Aral Sea. The study was carried out as part of the research plan of the Research Institute of Soil Science and Agro chemistry on applied and fundamental projects on an applied topic: .KHA-7-006-2015 “A comprehensive study of the irrigated soils of the lower reaches of the Amu Darya, fertility assessment, the establishment of lands subject to degradation, the improvement of their ecological and land reclamation conditions and the development of recommendations for restoring their fertility” (2015-2017), as well as fundamental KHF-5-006 topic “The formation and transformation of the soil cover of the Aral Sea region under conditions of climate change” (2017-2020).
soil maps, soil cover, fertility, landscape, global, climate change, anthropogenic, Amu Darya, delta, hydromorphic salt marshes, dynamics of irrigated soils.
Today in the world, the desertification process covers 36-40 percent of the continent’s surface and its further growth can be connected on the Rifit plume in Africa, Chad, the Atacama Desert in North and South America, in the great basin of the West, in Asia, the disappearance or intensive reduction of Chan, Balkhash, Aral. On June 17, 1994, a convention was adopted in Paris in order to mitigate the impact of the desertification process and to seek their resolution. Improving the properties and characteristics of low-fertile soils subject to degradation and desertification, their reclamation state, as well as effective use is one of the urgent tasks. At this time, scientific research is being carried out all over the world on the establishment, prevention and mitigation of desertification of soil cover in the following priority areas. In particular, special attention is paid to the implementation of scientific research aimed at preventing desertification processes arising under the influence of increased anthropogenic pressure and global climate change, improving the reclamation-ecological state of soils, combating irrigation soil erosion, protecting soils from secondary salinization, and also on the efficient use of soils subject to desertification. At the end of the 1950s and beginning 1960s, the water flow of the Amudarya and the Syrdarya declined sharply, which led to significant changes in the natural and ecological situation in the Aral Sea area. With the draining of the Aral Sea – the process of desertification, changes in soil formation conditions began here. A decisive role in soilforming processes began to play the arid-zonal factor, which led to a sharp transition of hydromorphic soils to automorphic desert soils. Such a rapid transition, when for a few years the groundwater level has significantly decreased and soil has dried up, predetermined the peculiarities of their evolution in the first stage of aridization. As a result of the development of evolutionary processes, the evolutionary soils have fallen out of evolutionary chain and the transition from meadow soils to marshy soils, characteristic for the ancient lowland plains of the lower reaches, has been erased. The genesis of soils at this stage, with the exception of solonchaks, is almost completely determined by the features inherited from the preceding, initial soil-forming processes.
Soil cover of the aral sea region and change of soil properties under the influence of desertification (on the example of soils of the karakalpakstan region) 621
To date, scientific research has been carried out, scientific developments have been developed and certain results have been achieved to identify changes in the soil cover of the Aral Sea region under the influence of desertification processes. In the action strategy of the Republic of Uzbekistan, for 2017-2021, important tasks are identified for "...mitigating the impact of global climate change and the drying of the Aral Sea on the development of agriculture and the life of the population". Identification of the processes of degradation and desertification of the Aral Sea region, mitigation of the influence of existing negative processes, conservation, enhancement and management of soil fertility, rational use of land, research aimed at protecting the soil and the development of scientifically based land reclamation activities is gaining importance. The study of the irrigated soils of the Aral Sea region, the study of their agrochemical, physic-chemical, biological and other properties, land reclamation, soil evolution, their humus state, soil quality assessment, conservation, restoration and improvement of their fertility were carried out by many domestic and foreign scientists. Such as V.V Bartold, N.G. Stoletov, N.A. Dimo, B.B.Polynov, B.V.Fedorov, L.T.Tursunov [17, 18, 24, 29], V.G.Popov [13, 14], A.Z.Genusov [6], N.V.Kimberg [6], R.K.Kuziev [8, 9, 10], I.T.Turapov, M.M.Tashkuziev, S.Abdullaev, R.Kurvantaev, V.E.Sektimenko [23, 24], N.Yu.Abdurakhmonov [21], A.Zh.Ismonov [9, 16], A.U.Akhmedov [21], H.K.Namozov, L.L.Suishov, G.V. Stulina, K.Yansgiya, F.A.Shinner, R.Niederbacher, R.Barta, M.Seto, B.R.Ramazonov [16, 17, 18, 19, 20, 21, 22], I.P.Gerasimov [7], B.A.Armor [1]Dukhovny V.A [3], Rafikov V.A. [15], Felician I.N. [4, 5], Shelayev A.F. [25],Tairov T.M. [27]etc. However, information about the changes that have occurred in the soil cover of the Aral Sea region, under the influence of desertification, are currently insufficient. Scientific studies to determine changes in soil properties due to drought and desertification processes resulting from global climate change and the drying up of the sea, as well as to prevent or mitigate the negative processes occurring in the soil cover, have not been carried out adequately.
The main objective of the study is to establish the transformation of the soil cover of the Aral Sea region under conditions of climate change, to determine changes in the properties and characteristics of common soils, as well as to develop a set of measures aimed at eliminating the negative processes occurring in them. The objective of the research is a comprehensive study of the soil supporting properties selected in the Aral Sea region, the establishment of a modern reclamation state, agrochemical, agrophysical soil properties; compilation of soil maps of selected farms with a scale of 1:10000, agrochemical cartograms, and on their basis, development of recommendations for restoring soil fertility; study of the features of soil cover transformation due to a sharp change in soil formation processes, under the influence of the drying of the Aral Sea in the ancient and old "living" Amu Darya delta; determination of changes, including negative ones, resulting from desertification of the territory by comparing research results with data from previous studies; development of a set of measures aimed at preventing and mitigating the negative processes occurring in the soil cover as a result of desertification caused by climate change over the past 60-70 years and improper redistribution of water reserves in the Aral Sea region. The object of the study is irrigated meadow-alluvial, meadow-takyr, takyr-meadow and grey-brown fallow, takyr, desert-sand, solonchak, residual-bog and coastal semi-hydromorphic solonchak soils widespread in the Aral Sea region. The scientific novelty of our research in the Aral Sea region is as follows: it has been established that due to global climate change in the last 60-70 years, redistribution of water reserves, increased anthropogenic load, desertification of the Aral Sea soil cover and changes in the soil cover are manifested; features of soil cover transformation as a result of a sharp change in soil formation processes in the ancient and “living” river deltas were established; compiled large-scale soil maps of irrigated and virgin areas of typical farms and determined salinization of soils, their supply with nutrients; it was found that in the Aral Sea region under the influence of desertification, the hydromorphic soil formation regime changed to automorphic and the areas of grey-brown, takyr, desert-sand and solonchak soils corresponding to the desert zone increased proportionally; based on the determination of the negative processes occurring in the soil cover of the Aral Sea region, scientific recommendations have been developed aimed at preventing or mitigating these processes. The scientific significance of the research results is explained by the determination of the properties of manifestation of desertification processes in the Aral soil cover and changes in the soil cover due to global climate change in the last 60-70 years, the redistribution of water reserves, the disclosure of soil cover transformation as a result of a sharp change in soil formation processes in ancient and "living" river deltas, the establishment of a transition from hydromorphic to automorphic, under the influence of desertification and in proportion to its increase in area EPO-brown, takyr, desert-sandy and saline soils corresponding to the desert zone. The practical significance of the research results lies in the fact that we developed recommendations to improve soil fertility and productivity, prevent salinization and other degradation processes, compiled soil maps and agrochemical cartograms of a scale of 1:10000 providing irrigated areas of typical farms with mobile phosphorus and exchange potassium, these measures serve to preserve, restore, increase soil fertility, obtain high crop yields and rational use of land eh. In this article we are talking about the soil cover of the Aral Sea region and the state of its study in connection with the drying processes of the Aral Sea, the soil and the history of the study of the soil cover of the territory are given. Literary information on the research on the topic of the dissertation in the republic is also given. The results of scientific research carried out in the framework of domestic and foreign projects on drying the Aral Sea and mitigation of its influence are also
Jour of adv research in dynamical & control systems, vol. 12, special issue-06, 2020
622
DOI: 10.5373/JARDCS/V12SP6/SP20201072 *Corresponding Author : Bakhtiyor RamazonovichRamazonov Article History: Received: Mar 24, 2020, Accepted: June 27, 2020 described in detail, the need for scientific research to study the current state of the soil in the territory and to develop solutions aimed at mitigating the effect of desertification on them is substantiated. The studies were conducted under conditions of irrigated meadow-alluvial, meadow-takyr, takyr-meadow, as well as grey- brown, takyr, takyr, desert-sand, residual-meadow, salt marshes, residual-bog soils and semi-hydromorphic coastal areas salt marshes, soil-field research and cameral-analytical work were carried out on the basis of generally accepted methods developed at the Research Institute of Soil Science and Agro chemistry, as well as "Instructions for soil and investigations and compilation of soil maps for maintaining the State Land Cadaster ”(2005). On soil samples from soil sections and field experiments, selected on the basis of genetic and geographical studies, chemical analyzes were performed using the following methods: soil mechanical composition—using the Kaczynski pipette method; chemical and agrochemical analysis of soils - according to the method of E.V.Arinushkina and the methodological guidelines of the Union of NII; the separation of silt particles from the soil without chemical treatment was carried out according to R.Kh.Aydinyan (1947); the composition of the absorbed bases — by the Pfeiffer method according to T.P. Krueger (1977); field experiments, counts, observations were carried out according to the “Methodological guidelines for conducting field experiments” (UzNIIH, 2007), statistical processing of the results was carried out according to the method of B.A.Dospekhov.
The climate of the Aral Sea region is distinguished by a sharply continental climate and aridity. The extreme arid climate created a sharply continental climate in these territories. According to the Muynak and Nukus weather stations, the air temperature ranges from 9,8°C to 11,0°C and the average monthly temperature in the month of July is 26,3-27,1°C. It is noted that the maximum air temperature during the day is 46-48°C, in the winter months - on average from 6,9-7,6°C to 32- 35°C.
Name
stations I II III IV V VI VII VIII IХ Х ХI
ХII Год
Average air temperature, °С Muynak
-7,2 -6,6 0,3 8,3 17,3 22,9 26,3 24,9 19,5 11,0 3,9 -2,6
9,8 Kungirat -7,1 -4,9 2,5 11,5 19,0 23,0 25,8 23,9 17,6 9,5 2,4 -3,1
10,0 Chimbay
-7,6 -5,0 2,8 11,9 19,4 23,7 26,0 23,9 17,7 9,6 2,0 -3,8
10,0 Nukus
-6,9 -4,0 4,1 13,1 20,5 25,0 27,1 24,7 18,3 10,4 2,1 -3,0 11,0
Absolute moisture of average monthly air in mm Muynak
3,2 3,5
8,4 8,4 11,9 16,7 19,7 19,2 14,3 9,6 7,3 4,8
10,3 Kungirat 3,1 3,5
8,1 8,1 10,4 15,5 18,9 17,7 12,9 8,0 6,3 4,4
9,5 Chimbay
3,1 3,7
7,9 7,9 10,0 12,9 16,1 15,1 10,9 6,8 6,1 4,3
8,5 Nukus
3,1 3,5
5,7 7,7 9,3
12,7 15,1 14,3 10,4 6,7 5,7
4,4 8,2
Monthly average precipitation, in mm Muynak
10 9 14 14 10 7 3 5 4 8 10 11
10,5 Kungirat 10 9
11 7 3 3 2 6 10 12
10,8 Chimbay
10 9 17 12 7 4 1 2 1 4 9 11
8,7 Nukus
6 9 13 14 10 6 5 2 2 4 5 7 8,2 Average wind speed, m/s. Muynak
5,7 5,4
3,2 5,7
6,2 5,1
5,0 5,5
4,9 5,2
6,5 5,6 5,4 Kungirat 4,2
4,7 5,1
4,7 4,9
4,2 4,1
3,7 3,6
3,6 3,9
4,3 4,2 Chimbay
3,5 3,9
4,6 4,1
4,3 3,7
3,4 3,2
2,7 3,1
3,6 3,7 3,7 Nukus 4,1
4,3 4,9
4,5 4,6
5,1 4,8
4,2 3,5
3,3 3,5
4,1 4,1
The ancient and modern deltas of the Aral Sea region consist mainly of plains with a very weak slope, and the embankments and lowlands located between the channels of the operating and dried rivers have turned the general plain view into a number of complex reliefs. The soils of the Aral Sea region are formed mainly on 4 sediments. Firstly, sandy-clay alluvial, layered deposits formed in different periods; secondly, covering with varying degrees of vegetation and re-established sand deposits under the influence of winds; thirdly, carbonate dust-like saz and sand-clay deposits containing limestone; and fourth, eluvial-saz deposits
Soil cover of the aral sea region and change of soil properties under the influence of desertification (on the example of soils of the karakalpakstan region) 623
associated with effusive rocks. The territory of the Aral Sea region has a peculiar vegetation cover and the landscape structure is very diverse. 51 species of plant landscapes were identified and mapped here. In the Aral Sea region, one can distinguish wetland, tugai, halophytic, desert or steppe varieties of plants. Formations of wetland plants are especially found in areas of high humidity: Typha - cattail, Phragmitusaustralius - reed, Ceattophyllum - hornwort. As a result of the intensive reduction of wetland areas, plant varieties also decreased, and at the same time, the areas of vegetation distribution decreased. It is believed that in the temporarily flooded zones and lakes of the Aral Sea region, varieties of reed formations are very widespread. At the same time, human influence on soil formation processes is multifaceted and diverse. Deforestation, hayfields, animal husbandry, plowing and cultivating land, irrigation, applying various fertilizers and chemicals to the soil, together with the drying of the Aral Sea and desertification, led to a sharp reduction in biogeocenoses and plant formation, and in some cases to the extinction of the latter, also to the extinction of tugai forests. In order to prevent the movement of sand and salts from the Aral Sea on 500 thousand hectares of land, large-scale work is underway to cut furrows to plant forests (saxaul) and so far,saxaul has been planted on an area of 500 thousand hectares of dried bottom of the Aral Sea. The discovery of fresh water at a depth of 280-300 meters 200 km from the city of Muynak, around the island of BorsaKelmes, will lead to an increase in biodiversity and an improvement in the ecological condition of the region. In the Aral Sea region, hydromorphic and automorphic soils are common. Automorphic soils are widespread in the Aral Sea region and the signs of their soil formation are related to the lithological structure, topography and age of the terrain, the microclimate characteristic of each type of soil, hydrothermal regime, the chemical environment in the process of soil formation and other complex soil characteristics. In the massifs of Zhanadarya and Mulk of the Takhtakupir district, gray- brown, takyr, desert-sand and solonchak soils are widespread. When studying the genetic horizons of gray-brown soils, it was observed that their profile consists of layered, porous cortical layers, clay and compacted, with humus content in the sub crustal layer, insignificant thickness of soil horizons, and an increase in secondary carbonates formed under the influence of biological factors in the upper soil horizons. Accumulation of gypsum in subsoil horizons, and a predisposition to shale and the formation of salt marshes under the influence of dry climate. The surface of the soil is covered with a light gray crust with a thickness of 1-3 cm, under it there is a light brown horizon, finely layered, with a friable structure, the thickness of which is 10-12 cm. A powerful gypsum horizon begins at a depth of 40-50 cm of gray-brown soils. characteristic of these soils, and beneath it is a parent rock with a very dense deposition. The mechanical composition of gray-brown soils is loamy, but, despite this, the total number of fractions of coarse sand and pebbles, with a diameter of more than 1-3 mm, does not exceed 2-3% on the surface of the gypsum-bearing layer. The main part of carbonates is located on the surface of soils and is biologically formed for a long time, the gypsum horizon consists of weathered, under the influence of long-term exposure to wind, a combined mixture of fibrous and porous gypsum, its thickness reaches 30-60 cm, and in some cases up to 100 cm the amount of gypsum in this horizon is 30-60%, and sometimes 90%. These soils are solonchak soils, containing at varying depths certain amounts of sulfate and chloride salts, and traces of solonetzization can be found in the crustal horizon. In the upper horizons of gray-brown light loamy soils, the content of coarse sand particles averages 16,6-43,0%, dust particles – 9,5-19,5%, silty particles – 2,1% and physical clay 29,5%, and have a loamy mechanical composition. By mechanical composition, takyr soils are mainly light loamy, sandy loamy, and some horizons are made of sand, coarse sand predominates over coarse dust particles. Since these soils are developed in a dry climate, where a small amount of precipitation falls, a slow course of humus formation processes is noted, due to the slow course of mineralization of organic residues. A certain pattern was noted in the distribution and diversity of these soils: insignificant humus contents of 0,5- 1,0% and the thickness of the humus horizon range from 15-20 cm. In the sod horizon of gray-brown soils, the humus content averages from 0,966% to 1,146 %, in the lower part of the soil profile, starting from 60-70 cm, its amount on average ranges from 0,356-0,400%. In the upper horizons of takir soils, humus is in the range of 1,016-1,045%, and in the lower horizons it is about 0,76%, the number of carbonates is on average from 9,131% to 9,820%, gypsum 0,10-0,15% and they are found in small quantities.
Jour of adv research in dynamical & control systems, vol. 12, special issue-06, 2020
624
DOI: 10.5373/JARDCS/V12SP6/SP20201072 *Corresponding Author : Bakhtiyor RamazonovichRamazonov Article History: Received: Mar 24, 2020, Accepted: June 27, 2020 Download 422.53 Kb. Do'stlaringiz bilan baham: 
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