CC BY
28
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
НАУКИ О ЗЕМЛЕ SCIENCES OF EARTH
УДК 631.4 DOI 10.18522/1026-2237-2020-1-26-35
SOILS OF BUYANT RIVER BASIN: TYPES, PROPERTIES, AND RELATION TO OTHER ENVIRONMENTAL PARAMETERS
© 2020 D. Battsetseg1, Ch.L. Khagvasuren1, O. Batkhishig2, Kh. Zoljargal
1Khovd University, Khovd, Mongolia, 2Institute of the Geography and Geoecology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
ПОЧВЫ БАССЕЙНА РЕКИ БУЯНТ: ТИПЫ, СВОЙСТВА И ОТНОШЕНИЕ К ДРУГИМ ЭКОЛОГИЧЕСКИМ ПАРАМЕТРАМ
Д. Баттцэцэг1, Ч. Лхагвасурэн1, О. Батхишиг2, Х. Цолжаргал2
1Ховдский университет, Ховд, Монголия 2Институт географии и геоэкологии, Монгольская академия наук, Улан-Батор, Монголия
Battsetseg Dugersuren - Postgraduate, Lecturer, Department of Баттцэцэг Дугерсурэн - аспирант, преподаватель, ка-Geography and Geology, Khovd University, 16/4300, Jargalant федра географии и геологии, Ховдский университет, sum 8400, Khovd, Mongolia, e-mail: [email protected] 16/4300, Ховд, Монголия, e-mail: [email protected]
Lkhagvasuren Choijinjav - Doctor of Geography, Professor, Department of Geography and Geology, Khovd, University, 16/4300, Jargalant sum 8400, Khovd, Mongolia, e-mail: [email protected]
Batkhishig Ochirbat - Doctor of Geography, Head of Soil Laboratory, Institute of the Geography and Geoecology, Mongolian Academy of Sciences, 81, Baruun Selbe 15, Chingeltei District, 4th Khoroo, Ulaanbaatar, 15170, Mongolia, e-mail [email protected]
Лхагвасурэн Чойджинджав - доктор географических наук, профессор, кафедра географии и геологии, Ховдский университет, 16/4300, Ховд, Монголия, e-mail: hovd_lha157@yahoo. com
Батхишиг Очирбат - доктор географических наук, заведующий почвенной лабораторией, Институт географии и геоэкологии Монгольская академия наук, 81, г. Улан-Батор, 15170, Монголия, e-mail [email protected]
Zoljargal Khavtgai - Doctor of Geography, Head of Soil La- Цолжаргал Хавтгай - доктор географических наук, за-boratory Institute of the Geography and Geoecology, Mongo- ведующий почвенной лабораторие, Институт географии lian Academy of Sciences, 81, Baruun Selbe-15, Chingeltei и геоэкологии, Монгольская академия наук, 81, г. Улан-District, 4th Khoroo, Ulaanbaatar, 15170, Mongolia, e-mail: Батор, 15170, Монголия, е-mail: [email protected] zoljargalk@gmail. com
Buyant river basin is one of the most elevated river basins of Mongolia. Its total area is 8488.7 km2, and the basin, administratively, occupy the territories of 33 bags belonging to 5 soums of Khovd (Duut, Jargalant, Buyant, and Khovd) and Bayan-Ulgi (Deluun) aimags. For the past 300 years, bottoms of the basin used for agriculture while majority of rest land exploited by traditional nomadic livestock breeding. The soils in the basin is contrast due to its altitudinal differences. There are 35 types of soils belonging to 18 soil groups of 9 orders are distributed in the Buyant river basin. The purpose of this paper is to define quantitative analysis for soil and it properties and identify external linkages with other natural factors and socioeconomic indicators. The research is employed basic soil laboratory analysis following traditional methods. For the factor analysis, the multiple linear regression analysis is used. According to the results, the soils in the Buyant river basin are generally low fertile with sandy and sandy clay texture. The soil physical properties largely dependent on climate change, aridity, and land use. Besides, abovementioned natural factors and their impacts of soil properties the soil itself define social processes going on in at the basin level.
ISSN 1026-2237 BULLETIN OFHIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
Keywords: Buyant River basin, soil properties, salinity, carbonate, texture, soil organic matter, pH, available potassium, phosphorus.
Бассейн реки Буянт относится к наиболее возвышенным речным бассейнам Монголии. Его общая площадь составляет 8488,7 км2. На его территории располагаются 5 сомонов, относящихся к двум аймакам: Ховдскому (сомо-ны Дуут, Джаргалант, Буянт и Ховд) и Баян-Улгийскому (Делюун). Район исследования характеризуется высокой изменчивостью природных условий, определяемой высотной поясностью. Здесь выделено 9 групп, 18 типов и 35 родов почв. На состояние почвы долины реки оказывают воздействие различные секторы экономики, включающие традиционное животноводство, а также выращивание зерновых, картофеля и овощей, которое проводится более 300 лет. Основной целью исследования являются анализ почвенных характеристик и физических свойств почвы в бассейне реки Буянт и выявление связей с другими природными факторами и социально -экономическими показателями. При проведении исследования использовался базовый лабораторный анализ почвы с использованием традиционных методов, а также множественный линейный регрессионный анализ. Установлено, что почвы в бассейне реки Буянт, как правило, обладают песчаной и песчано-глинистой текстурой и являются малоплодородными. Физические свойства в значительной степени зависят от изменения климата, засушливости и вида землепользования. Кроме того, характеристики почвы определяют социальные процессы, происходящие на уровне речного бассейна.
Ключевые слова: бассейн реки Буянт, свойства почвы, засоленность, карбонаты, текстура, органическое вещество почвы, pH, доступный калий, фосфор.
Introduction
Buyant river is one of the largest tributary rivers of the Khovd river, which is located in the Central Asian Internal Drainage Basin. Its headwaters formed in high mountains of the Mongolian Altai region. The Buyant river stretches through about 195 km and passes several natural regions: high mountain steppe, dry steppe, and desert steppe. Besides, its natural uniqueness, the Buyant river, has a tremendous socio-economic impact on society. One of the largest cities of Western Mongolia - Khovd city - is located on the banks of this river. Since 1685 the estuaries of Khovd and the Buyant river used for agriculture to supply the region with significant crops and vegetables [1].
The first soil survey over the region is conducted in a framework of expeditions led by the Mongolian Commission (a former scientific collaboration between the Soviet Union and Mongolia). This research aimed to assess soil fertility and possibilities to expand current agriculture practice. The researches led by Prof. Andreev [2] occupied only estuaries of the Buyant river where small-hold agriculture practiced for many years.
In 1960-1980, the soil research in rangelands and agricultural field was initiated by the Government of Mongolia. As a result of this nation-wide initiative series of soil maps with the scales of 1:100000 and 1:200000 are developed, and one of which dedicated to the Buyant river basin [3].
Besides researches mentioned above, several other expeditions were organized in the region and mainly dealt with soil fertility issues [4-8].
The Buyant river stretched through the different surfaces with unique landscapes, the contrast of which can be observed within a short distance. The soil cover in the basin is also diverse. The most soil
types identified in a region characterized by sandy loam structure, stony throughout all horizons, and low fertility. Majority of land used for traditional nomadic livestock breeding and only territories close to Khovd city used for various types of land use in major for small-hold agriculture.
This research aims to introduce the major types of soil in the Buyant river basin, provide characteristics of the soils and identify which environmental parameters they are linked to.
Materials and methods
Study area
The Buyant river basin located in Western part of Mongolia (N 47.343°-48.318° and E 90.065°-92.214°), and covers an area of 8488.7 km2. Administratively, the basin occupy the territories of 33 bags belonging to 5 soums of Khovd (Duut, Jarga-lant, Buyant, and Khovd) and Bayan-Ulgi (Deluun) aimags.
If to take an altitudinal belts, totally 14.1 % of total territory belonging to the Buyant river basin are that the altitudes of more than 3000 m, 62.8 % with altitudes of 2000-3000 m, and 23.01 % are at the altitudes of 1157-2000 m ASL (Fig. 1). The basin, therefore, can be considered as one of the highly elevated river basins in the country.
The climate of the basin is distinct continental with harsh and cold winter and dry and hot summer. According to the selected three station in upper (Deluun), middle (Khovd), and down (Myangad) stream of the Buyant river, the temperatures range between -3.7...-0.8 °C in upper stream area, between -1.04...2.57 °C in a middle stream and between -1.04...3.28 °C in downstream areas. In the winter the Northern parts of the basin highly impacted by
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
Asiatic anticyclone the average temperatures for regions of the country due to its elevated surface. The
January in down streams is -25.18 middle streams average temperatures for July in down streams is
is -23.93 X, and in upperstreams is -21.9 °C The 21.39 middle streams 20.78 and in
summer is relatively chilly comparing to other natural upperstreams is 14.9 °C
Fig. 1. Buyant river basin, its location, and distribution of sampling points / Рис. 1. Бассейн реки Буянт: его местонахождение и положение точек отбора проб
The average rainfall of the region varies between 100 and 150 mm per annum. Similarly, more than 70 percents of total rainfall falls in June, July, and August.
In terms of socio-economy, the Buyant river basin is inhabited by 45614 people from 11760 families. The primary landuse type is rangeland, with total number of livestock by 2018 is 756 thousands. The second largest land use type is agriculture. By 2018, the basin had around 5000 hectares of agricultural fields with total productivity of 17000 tons. The principal crops are potatoes, cereals, and vegetables.
Sampling
The field researches were implemented during April-Septmeber of 2014-2017. Totally 300 samples were collected from 90 sites (Fig. 1). Moreover, to compare results data and information provided in liter-
ature were extracted and compared. Besides, direct soil parameters, the natural and socio-economic information for the basin were obtained from large amount of sources. Soil samples were taken under Mongolian National Standards MNS 3298:1990 [9]. The samples were taken by excavating a pit with dimesions 70-80 cm by 120-130 cm and using standard methods for disturbed soil sampling for each soil profile its morphological descriptions has given.
Dataset
The soil analysis were carried out by the Soil Laboratory of the Institute of Geography and Geoecolo-gy at Mongolian Academy of Sciences, Mongolia, Laboratory of Soil Biochemistry of the Nart Research and Experimental Center, Mongolian University of Life Sciences, Mongolia, and in the Soil Laboratory of the Inner Mongolia Normal University, PRC.
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
The regional meteorological dataset were obtained from the Khovd branch of the National Meteorological Agency of Mongolia. The surface characteristics were extracted from the digital elevation model by Suttle Radar Topography Mission (SRTM -http s: //www2 .jpl.nasa. gov/srtm/) [10].
The socio-economic data for the administrative units territorially belonging to the Buyant river basin is provided by the National Statistical Data Portal (www.nso.mn) [11].
Methods for laboratory analysis
All soil samples were air dried and sieved with 2 mm sieves before analysis [12]. The soil pH and EC were determined with a suspension of 1 part soil by weight to 2.5 parts liquid by volume using glass electrode pH meter [13].
Soil organic matter was determined using Turin method. The method is based on the oxidation of organic matter. Depending on the humus content samples of 0.05-1.0 g are taken from the samples and after a dichromate digestion with 10 ml 0.4 N oxidizing solution (K2Cr2O4: H2SO4 - 1:1) at 120 °C for 45 minutes in presence of catalyser Ag2SO4, the consumed oxidizer (oxidizing agent) is determined by titration with Fe(NH4)2(SO4) 6H2O using phenylanthranilic acid as an indicator [13].
The soil texture is determined by hydrometer method by A.N. Kachinsky [15].
The available phosphorus and potassium content was identified according to the Machigin method [16]. Soil carbonate was measured by using calcimeter apparatus [17].
Methods for data analysis
The descriptive statistics to obtain mean, standard deviation, analyses of variance has performed using standard methods. The soil texture were analysed using twelve major soil texture classifications are defined by the USDA [13].
The linear relationship between soil characteristics and other environmental factors is calculated by the Pearson correlation coefficient as follows.
r=
xy
z*-i(x- xh - y ) a/s?-i(X -xNZ?-i(i -Y)2
(1)
Multiple regression analysis was carried out in the transformation of soil properties.
y = Po + P\X\ +si, (2)
y = Po +A*l + P2 X2 +•• ' Pnxn + s , y - dependent variable; x - independent variable; P0 - intercept; px - slope coefficient; s - error. The primary condition for analysis is that the mean error is 0.
All data analysis is performed on SPSS 22 environment.
Results and discussion
Soils of the Buyant river
According to O. Batkhishig (2016), there are 35 types of soils belonging to 18 soil groups of 9 orders are distributed in the Buyant river basin [18].
The upper streams of the Buyant river are mountainous; thus the soil distribution follows altitudinal gradients. The uplands, generally, formed with mountain, primitive types of soil, and, along the altitudinal gradient, the soil depth is increasing.
The primary soil type of the uplands of both the Mongol Altai Mountain and the Huh Serh Mountain (2700 m elevation) are Umbrisols, and Cryosols, which can be found at the altitudes up to 2500-3000 m. Over the slopes and foots of the mountains, the soils become more dry due to the climatic inversion. Here the majority of soil cover presented by Aridic Leptosol and its variations. The bottoms of hollows, estruaries, and lowlands in majority covered by saline variations of major soil types, e.g., Calcisols, Leptic, and Leptic aridic Kastanozems. Across the hills and terrain of the river basin, Calcisols and Leptic Calcisols are wide-spead. Surrounding the Buyant River the alluvial types of soils, e.g., Mollic, Loamic, Gleyic and Cryic Fluvi-sols, can be identified. The bottoms, estruaries of the lowlands sometimes are covered by Solonetz, the most saline forms of soils.
The Buyant river has created many deltas above the Ulaan Bogoch mineral spring of the Khovd city. This delta is the most fertile part of the basin where the central agricultural zone is situated. Due to long-lasting irrigated farming practices, the properties of Loamic Fluvisols and Calcisols have changed. Dr. O. Bat-khishig [18] described these changed soils as an agricultural soil with uniform soil profile throughout all its horizons. The surrounding area of Har Us lake is a distribution os Histosols where the most dense vegetation cover is formed due to its constant moisture regime. In the land use, the are of Har Us lake is used for hay making for a long history of the development of region [18].
The soils in/around large towns and cities are considered as a Technosols and are mainly highly disturbed by human activities. These types of soils has no vegetation cover, highly compacted, and very polluted by waste.
Soil characteristics
For the purpose to define the capacity of soils for use as well as characterize each type of soil in the Buyant river basin, the ranges of soil pH, carbonates, eclectric conductivity, available phosphorus and potassium, and soil texture were selected for further analysis. In the Table 1, the descriptive statistics of soil properties in the river basin are shown.
ISSN 1026-2237 ИЗВЕСТИЯ ВУЗОВ. СЕВЕРО-КАВКАЗСКИЙ РЕГИОН. ЕСТЕСТВЕННЫЕ НАУКИ._2020. № 1
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
Table 1
Physical and chemical properties of soil of Buyant river basin / Физико-химические свойства почвы бассейна реки Буянт
Properties pH CaCO3, % SOM, % EC, dS/m P2O5, mg100g1 K2O, mg 100g1 Sand, % Silt, % Clay, %
n 237 237 237 237 196 196 237 237 237
Mean (A) 7.65 1.27 2.00 0.3 2.08 19.07 55.60 31.96 12.44
Mean (B) 7.71 1.94 0.76 0.18 1.03 9.48 56.54 31.82 11.64
Min 6.17 0.00 0.018 0.005 0.11 1.00 3.70 4.20 0.20
Max 9.60 21.81 6.500 3.84 6.33 85.70 93.60 70.60 25.70
Results of analysis showed soil pH in the river basin was from slightly acidic to strongly alkaline ranged as 6.17-9.6. Soil average pH of horizon A was 7.65, and horizon B was 7.71; therefore these soils are slightly alkaline [19]. The uplands of the river basin are mountainous; likewise mountain soil pH ranges from slightly acidic to neutral pH. Within the uplands to the bed of the river basin, alkalinity increased, so Calcisols pH was moderately alkaline. A horizon of Fluvisols pH in the Buyant river was moderately alkaline and the C horizon was slightly alkaline. Solonetz pH in horizons A and B became moderately to strongly alkaline (Table 1, Fig. 2). Considering that the optimum pH range for
most plants is between 5.5 and 7.5 [20], the sparse vegetation cover formed on mountains somehow depends on soil pH.
Carbonate content ranged between 0-21.81 %. Average carbonate content of horizon A was 1.27 %, and В horizon was 1.94 %. The carbonates in Umbrisols and Antrosols are washed out due to irrigation and leaching, Ad and A horizons of Fluvisols and Histosols were carbonated. However, AB and B horizons did not include carbonate. Between the A to B horizon, carbonate content increased more in Mollic, Aridic, and Lithic leptosols. Carbonate content increased less in Natric Calcisols between the A and B horizons (Table 1, Fig. 2).
b
a
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
e
Fig. 2. Soil properties of Buyant River basin (a - soil pH, b - soil organic matter, c - electrical conductivity, d - carbonate, e - available phosphorus, f - available potassium, g - clay, h - silt, i - sand) / Рис. 2. Свойства почвы бассейна реки Буянт (а - pH почвы, b - органическое вещество почвы, c - электрическая проводимость, d - содержание карбоната, e - доступный фосфор,
f - доступный калий, g - глина, h - ил, i - песок)
Soil organic carbon in the soil is an essential part of the ecosystem. Soil in the river basin is dominated by a consistency with less organic matter and nutrients. The contents of organic matter, available phosphorus, and potassium is decreasing from horizon A to C. Soil organic matter ranged between 0.018-6.5 %. Average SOM content of horizon A was 2 % and B horizon was 0.76 %. Soil organic carbon of Um-
brisols is ranging between 4.34 and 6.5 % on the Northern slopes of the Mongol Altai Mountains. In the surrounding area of Chigertei mineral waters, this was the maximum value for this river basin. Antrosols soil organic carbon decreased due to long term planting and ploughing (Table 1, Fig. 2).
The soil salinity is determined by recent electrical conductivity testing. By definition, saline soils have a
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
high concentration of soluble salts, and an EC is greater than 1 dS/m. Electrical conductivity of the river basin ranged between 0.005-3.84 dS/m. The average content in the A horizon was 0.3 dS/m, while the В horizon showed 0.18 dS/m. EC of Histosols, Fluvisols, Solonetz, Technosols and Antrosols increased in the A horizon and EC of Umbrisols and Leptosols increased in B horizon (Table 1, Fig. 2).
Soils of the Buyant river basin are characterized by Loamy sand, Sandy loam, and Loam texture. From the uplands to the bed of the river basin, silt and clay contents ranged between 39.32-16.7 % and 14.7-7.5 %, respectively. Sand content ranged between 46.6-75.8 %. The maximum value of silt reached 25.7 %, which shows that soil of the Buyant river basin is light texture (Table 1, Fig. 2).
As shown Fig. 2, sand content, and pH were increased from upper to bed of river basin but organic
Factors impacting the soil properties The Buyant river basin occupies different natural forms, e.g., high mountains of Mongolian Altai, desert steppes, and gobi of the Great lake Depression. Such geographic heterogeneity defines the formation of several natural zones within the river basin, which is logically impacting on soil cover and its characteristics. In order to determine which external factors or determinants influencing on soil properties the multiple regression analysis and correlation analysis are performed. The results of correlation analysis of external factors, e.g., average air temperature, precipitation, wind, elevation, slope, aspect total number of population and live-
matter, available phosphorus, silt and clay content were decreased from upper to bed.
The regression analysis is performed in order to determine which parameter is closely related to soil fertility. The results showed that the sand content showed significant negative correlations with SOC, available potassium, clay, and silt content (P<0.01). Sand content showed significant and positive correlations with EC, available phosphorus, and carbonate content (P<0.05). Silt and clay showed significant and positive correlation with SOC, available potassium (P<0.01), and carbonate (P<0.05). The silt content is showed positive correlation with EC and clay and positively correlated with available phosphorus (P<0.05). The SOC is showed positive correlation with available phosphorus and potassium (P<0.01). The soil pH has had a negative correlation with SOC and AP. Soil pH, carbonate, and EC showed positive correlation each other (Table 2).
Table 2
stock density, has shown in Table 3 and 4. Multiple regression analysis is performed by stepwise and provides a linear equation with many independent variables that affect the soil properties (Table 4). Dependent variables are soil quality properties, and independent variables are the external factors mentioned above.
According to the results of the multiple regression analysis, the elevation has shown a significant impact soil properties among all other external factors. In addition to the impacts of external factors on soil characteristics, the soil have also showed significant relation to external factors. For instance, the soil pH is directly linked to the population number.
Correlation between soil properties / Корреляция между показателями свойствами почвы
Sand Silt Clay SOM P2O5 K2O pH CaCO3 EC
Sand -.979** -.879** -.446** -.301* -.439** .200 -.301* -.308*
Silt ** .764** .439** .268 .397** -.219 .286* .315*
Clay ** ** .384** .330* .466** -.125 .288* .239
SOM ** ** ** .354** .459** -.285* .163 .304*
P2Û5 * * ** .541** -.366** .061 .133
K2O ** ** ** ** ** -.043 .510** .639**
pH * ** .375** .289*
CaCO3 * * * ** ** .507**
EC * * * ** * **
** - correlation is significant at the 0.01 level (2-tailed); * - correlation is significant at the 0.05 level (2-tailed).
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
Table 3
Correlation between impact factor and soil properties / Корреляция между факторами воздействия и свойствами почвы
Sand Silt Clay SOM P2O5 K2O pH CaCO3 EC
Elevation -.456** .461 .367 Л Л 1 ** .441 .470** .268 -.639** -.057 -.246
Slope -.177 .198 .099 .331* .231 .167 -.478** .039 -.253
Aspect -.184 .206 .100 .088 .251 .097 -.147 -.281* .072
Temperature .457** -.481** -.323* -.361** -.413** -.176 .527** .059 .188
Precipitation -.198 .167 .239 .330* .252 .408** -.373** -.093 -.039
Wind _ __ ** .372 -.333* -.399** -.173 -.082 -.385** .090 -.215 -.026
Density of population .063 -.075 -.024 -.233 .030 .123 -.070 .034 .162
Density of livestock .072 -.083 -.033 -.238 .024 .123 -.057 .035 .168
** - correlation is significant at the 0.01 level (2-tailed); * - correlation is significant at the 0.05 level (2-tailed).
Table 4
Regression analysis equation with affected factors on soil properties / Уравнение регрессионного анализа под влиянием факторов на свойства почвы
Regression equation R R. Sq Sig.
YpH =-°.257-°.961 XElevation -0.507Xwind+0.3 5 3XTemperature -1.98X Density population 0.773 0.597 0.000
YcaCO3=0.35-0.269X Aspect 0.281 0.079 0.043
YsoM=0.205+0.477X Elevation 0.44 0.195 0.001
YP2O5=°.205+°.535X Elevation 0.494 0.244 0.000
YK2O=°.°76+°.427X precipitation 0.375 0.141 0.006
Ysand=-0.212-0.492X Elevation 0.456 0.208 0.001
Yclay=0.082-0.383X wM 0.414 0.171 0.002
Discussion
In Buyant river basin, the majority of the land is used as a rangelands (837 thousand ha); the urban and agricultural land occupy only 0.8 and 0.7 percent of total land area. Eventhough the traditional livestock breeding considered as highly adapted to climate change and suitable for the vast steppe area, several negative consequences have observed in Buyant river basin since the privatization and transition economy time. Firstly, the number of livestock is doubled leading to decreased pasture carrying capacity. To date, the pasture carrying capacity have exceeded 1.6 times. This socio-economic transformation is impacting soil cover as high number of livestock trampling the soil cover, increasing erodibility by reducing vegetation cover, and increasing soil pollution.
According to J. Garidkhuu et al. [4], the soils of Buyant river basin is saline and stony with sandy clay texture. In soil oraganic matter, the content of fulvo acids are prevailed, the content of nitrogen is low, while the amount of potassium in topsoil layer is high [4]. The similar conclusion we can make for the soils distributed in estruaries of Buyant river. The soils here used in irrigated agriculture for past 300 years without any technological innovations. The only method for fertility enchancement is to use a manure. Unfortunately, only putting the manure is no longer can sustain the soil fertility the other biophysical techniques of soil processing has to be introduced.
Academician D. Dorjgotov (2003) is mentioned in his manuscript that along the 30 years of agricultural development on Kastanozems and Aridic Kastanozems, the soil fertility declined up to 1.8-2.1 % and SOM
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
sources reduced by 40 percents [21]. The similar trend probably happened for the soils in Buyant river basin; thus, the more specific time related researches over the significant soil properties are required in order to develop sound scientific justifications for soil protection and furtherer land degradation.
Conclusions
There are 35 types of soils belonging to 18 soil groups of 9 orders are distributed in the Buyant river basin. The primary external factors impacting soil formation processes as well as soil properties, are linked to surface, e.g., altitudes, inclination, and distribution of energy along the altitudinal gradient.
Soils in the Buyant river basin are generally low fertile with sandy and sandy clay texture. The soil pH in majority of soil samples used in this research showed that in uplands, it is slightly alkaline and alkalinity increased downward to the bottom of the basin.
The top soil horizon characterizes with relatively high contents of organic matter, available phosphorus and potassium comparing to lower horizons, e.g., B and C horizon.
The soil physical properties are largely dependent on climate change, aridity, and land use. Across the study area, the Technosols is highly compacted, the carbonate contents of Antrosols has leached, and the concentration of organic matter and nutrient elements are reduced. The horizon Ad in Fluvisols had much more carbonate contents and electrical conductivity than in other horizons.
Besides, abovementioned natural factors and their impacts of soil properties, the soil itself define social processes going on in at the basin level. For instance, the density of population has significantly correlated with soil pH level.
References
1. Gongor D. (1964). Brief history of Khovd. Ulaanbaatar, 227 p.
2. Andryeev S.E. (1935). Soils of the delta of the river Buyant and Kovdos economic. Proceedings of the Mongolian Commission. Leningrad, Academy of Sciences, no. 16, 42 p.
3. Munkhbat M., Suren Ch. (1977). Soil research report of Khovd province. Soil map of Khovd aimag 1:200000. Ulaanbaatar, Land Management Institute Press.
4. Garidkhuu J., Jamsran J., Birzana O., Banzragch D., Tsendee B. (1972). Soil agrochemistry in lake depression. Izvestiya Akademii nauk, no. 3, pp. 23-30.
5. Oyunchimeg T. (1998). Soil geochemistry and some characteristics in dried area. Dissertation. Ulaanbaatar.
6. Lkhagvasuren Ch. (2001). Distribution of some micro metals around Lake Khar-Us. Dissertation. Ulaanbaatar.
7. Strauss А., Schickhoff U. (2007). Vegetation zona-tion in a Western Mongolian lake shore-semi-desert eco-tone. Erdkunde, vol. 61 (1), pp. 72-92.
8. Yakutin M.V., Andreivskii V.S., Lhagvasuren Ch., Battsetseg D. (2014). Transformation of zoo-microbial complex in soils of the Southern part of the Great lakes Depression of Western Mongolia in conditions of desertification. Euroasian Eniomological Journal, vol. 13 (5), pp. 489-493.
9. MNS 3298:1990. Nature protection. Soil. General requirements on sampling for the analysis. Ulaanbaatar, Mongolian Agency for Standardization and Metrology Press.
10. Suttle Radar Topography Mission. Available at: https://www2.jpl.nasa.gov/srtm/ (accessed September 23, 2019).
11. National Statistical Office. Available at: www.nso.mn (accessed August 20, 2019).
12. MNS ISO 11464:2000. ISO 11464:2006. Soil quality -Pretreatment of samples for physico-chemical analysis. Ulaanbaa-tar, Mongolian Agency for Standardization and Metrology Press.
13. Soil Science Division Staff. (2017). Soil survey manual. C. Ditzler, K. Scheffe, and H.C. Monger (Eds.). Handbook 18. Washington, D.C., U.S. Gov. Print. Office.
14. Tjurin I.V. (1937). Soil organic matter and its role in pedogenesis and soil productivity. Study of soil humus. Moscow, Leningrad, Sel'skozgiz Publ., 285 p. (in Russian).
15. Vadyunina A., Korchagina Z. (1986). Methods of researching the physical properties of soils and ground. Moscow, Agropromizdat Publ., 416 p. (in Russian).
16. GOST 26205-84. Determining available phosphorus and potassium by Machigin method. Moscow, Committee for Standartization and Metrology Press. (in Russian).
17. GOST 34467-2018. Soils. Laboratory methods for determination of calcium carbonate content. Moscow, Standartinform Publ. (in Russian).
18. Batkhishig O. (2016). Soil classifications in Mongolia. Mongolia's Soil Study, no. 1, pp. 18-31.
19. Soil survey manual. Soil Conservation Service. (1993). Handbook 18. Washington, D.C., U.S. Gov. Print. Office, 437 p.
20. Queensland Department of Environment and Heritage Protection. Soil pH. Available at: www.qld.gov.au. (accessed May 15, 2017).
21. Doijgotov D. (2003). Soils of Mongolia. Ulaanbaatar: Admon Publ., 288 p.
Литература
1. Гонжор Д. Краткая история Ховда. Улан-Батор, 1964. 227 с.
2. Андреев С.Е. Почвы дельты реки Буянт и Ков-досое аймачное хозяйство // Труды Монгольской ко-
ISSN 1026-2237 BULLETIN OF HIGHER EDUCATIONAL INSTITUTIONS. NORTH CAUCASUS REGION. NATURAL SCIENCE. 2020. No. 1
миссии № 16. Л.; М.: Изд-во Академии наук СССР, 1935. 42 с.
3. Мунхбат M., Сурэн Ч. Почвенная карта Ховдаского аймака масштаба 1 : 200 000: отчет о почвенных исследованиях Ховдской губернии. Улан-Батор: Ин-т землеустройства, 1977.
4. Гаридхуу Ж., Джамсран Ж., Бирзана O., Бан-жрадх Д., Цэндээ Б. Агрохимия почв впадины озера Ачит // Известия Академии наук. 1972. № 3. С. 23-30.
5. Оюунчимег Т. Геохимия и некоторые характеристики почв в засушливых районах: дис. ... д-ра геогр. наук. Улан-Батор, 1998.
6. Лхагвасурэн Ч. Распределение некоторых микрометаллов в районе озера Хар-Ус: дис. ... д-ра геогр. наук. Улан-Батор, 2001.
7. Штраус А., Шикхофф У. Растительная зональность прибрежно-полупустынного экотона озёр Западной Монголии // Эрдкунде. 2007. № 61 (1). С. 72-92.
8. Якутин М.В., Андреевский В.С., Лагвасурэн Ч., Батцэцэг Д. Трансформация зоомикробного комплекса в почвах южной части Котловины Больших озер в Западной Монголии в условиях опустынивания // Евразийский энтомологический журнал. 2014. № 13 (5). С. 489-493.
9. MNS 3298: 1990. Охрана природы. Почва: общие требования по отбору проб для анализа. Улан-Батор: Монгольское агентство по стандартизации и метрологии, 1990.
10. Suttle Radar Topography Mission. Available at: https://www2.jpl.nasa.gov/srtm/ (accessed September 23, 2019).
11. National Statistical Office. Available at: www.nso.mn (accessed August 20, 2019).
12. MNS ISO 11464.2000. ISO 11464:2006. Качество почвы. Предварительная обработка образцов для физико-химического анализа. Улан-Батор: Монгольское агентство по стандартизации и метрологии, 2000.
13. Soil Science Division Staff. Soil survey manual. C. Ditzler, K. Scheffe, and H.C. Monger (Eds.). Handbook 18. Washington, D.C.: U.S. Gov. Print. Office, 2007.
14. Тюрин И.В. Органическое вещество почвы и его роль в педогенезе и продуктивности почвы // Изучение гумуса почвы. М.: Сельхозгиз, 1937. 287 с.
15. Вадюнина А.Ф., Корчагина З.А. Методы исследования физических свойств почв и грунтов. М.: Аг-ропромиздат, 1986. 416 с.
16. ГОСТ 26205-84. Почвы. Определение содержания фосфора и калия по методу Мачигина в модификации ЦИНАО. М.: Комитет стандартизации и метрологии, 1985.
17. ГОСТ 34467-2018. Грунты. Метод лабораторного определения содержания карбоната кальция. М.: Стандартинформ, 2019. 9 с.
18. Батхишиг О. Классификация почв в Монголии // Почвы Монголии. 2016. № 1. С. 18-31.
19. Soil Survey Division Staff. Soil survey manual. 1993. Soil Conservation Service Handbook 18. Washington, D.C., U.S. Department of Agriculture 1993.
20. Queensland Department of Environment and Heritage Protection. Soil pH. Available at: www.qld.gov.au. (accessed May 15, 2017).
21. Дороджготов Д. Почвы Монголии. Улан-Батор: Адмон аблишинг, 2003.
Поступила в редакцию /Received
10 октября 2019 г. / October 10, 2019
