Summary of Doctoral thesis in Geography: Study on soil geomorphology for planning and using land sustainably in Bac Tay Nguyen region

The research objective of the dissertation establishes geomorphologic geological units to serve as a scientific foundation for sustainable land use planning and use in the North Central Highlands. Building up the system of units and criteria and establishing geomorphologic map of the North Central Highlands. Analyzing characteristics and classification of geomorphologic landscapes, proposing solutions to sustainable land management and use on the geomorphologic viewpoint of North Central Highlands.

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY - NGUYEN VAN DUNG STUDY ON SOIL GEOMORPHOLOGY FOR PLANNING AND USING LAND SUSTAINABLY IN BAC TAY NGUYEN REGION Major: Geography of Resource and Enviroment Code: 44 02 20 SUMMARY OF DOCTORAL THESIS IN GEOGRAPHY Hanoi - 2018 The thesis is completed at: Graduate University of Science and Technology, Vietnam Academy of Science and Technology Supervisors: Ph.D Nguyen Đinh Ky Assoc Prof Ph.D Nguyen Dich Dy Reviewer 1: ……………………………………………… Reviewer 2: ……………………………………………… Reviewer 3: ……………………………………………… The thesis will be defended at Graduate University of Science and Technology - Vietnam Academy of Science and Technology, at hour ……date……month ……201 Thesis can be found in - The library of the Graduate University of Science and Technology - Vietnam’s National Library INTRODUCTION The necessity of the research Soil is a precious natural resource that most food supply to human are derived from V.V.Docutraev supposed that soil is an independent natural object, formed by the interaction of parent rock/ matter, terrain, climate, organisms and time factor These relationships are deeply researched into such directions: soil geomophology, soil-parent rock/material, soil-climate, soilorganisms In that the relationship of landforms and soils are considered the most dynamic and complex; can be explained on the basis of the balance between morphogenesis and pedogenesis In the organization of production and land use, the characteristics of the morphopedological (MP) landscape are important for economic efficiency and sustainability because using land, changing vegetation triggers exogenous processes (morphogenesis) to affect the soil cover, making it change If the land use is suitable with the rules of morphogenesis and pedogenesis, it is sustainable and effective If not, it is not sustainable and ineffective, leading to land degradation - desertification Bac Tay Nguyen (BTN) region accounts for about 50% of the total area of Tay Nguyen, including Kon Tum and Gia Lai, which has a wide variety and diversity of soil types It has most of groups and major soil types of Tay Nguyen With the characteristics of morphopedology of mountains, high plateau, always implies the process of natural hazards such as land degradation, landslide, floods, drought For the above reasons, the project "Study on soil geomorphology for planning and using land sustainably in Bac Tay Nguyen region" have been made in order to contribute to the solutions of the practical requirements and sustainable development of Tay Nguyen Research objectives Establishment of morphopedological units as scientific basis for planning and using land sustainably in Bac Tay Nguyen region Research implementations - Overview of researchs of soil geomorphology in domestic and foreign; - Establishing theoretical basis for research of soil geomorphology - Analyze the conditions that make up the MP landscapes in BTN - Build the system of classification, criteria and establishment of MP map of Bac Tay Nguyen at the rate of 1/ 250,000; - Analyze the morphopedological landscapes (MPL) in BTN - Analyze, assess the MP landscapes for land use in Bac Tay Nguyen - Proposing solutions for sustainable land use and management from morphopedological approach in Bac Tay Nguyen Research area and object - Research area: Bac Tay Nguyen, including Kon Tum and Gia Lai - Research object: geomorphology, soil in Bac Tay Nguyen region Protected points - Correlations of geomorphology and soil in Bac Tay Nguyen are presented characteristics, morphology of terrain and pedology, based on morphogenesis and pedogenesis in the MP landscapes - Bac Tay Nguyen is divided into 12 groups, 39 types of morphopedological landscapes, which are diverse and complex, so planning and using land must follow this division to achieve sustainable development and disaster prevention New points - The thesis is the first one to assess the relations of geomorphology and soil in Bac Tay Nguyen and present the relations on morphopedological map with scale 1/250.000 - Initially proposed a plan for spatial organization, planning and using land sustainably, simultaneously warning of natural disasters based on the analysis of characteristics, structure of morphopedological landscap in Bac Tay Nguyen region Scientific and practical contributions - Scientific contributions: contributing to the clarification of soil and geomorphology relationships in the tropics; and improvement of the MP method for planning, sustainable use of land resources - Practical contributions: The result of the project is the scientific basis for planning, territorial organization, sustainable use of natural resources and natural disaster prevention; It is also important data for soil survey and land assessment Viewpoints and methods of the thesis can be applied for Tay Nguyen and other areas with similar conditions The structure of the thesis Apart from the introduction, the conclusions and recommendations, reference and appendix, the thesis consists of chapters: Chaper Theoretical basis and research methods of soil geomorphology in Bac Tay Nguyen Chaper Conditions of formation and characteristics of morphopedological landscapes in Bac Tay Nguyen Chaper Assessment of morphopedological landscapes for planning and using land sustainably in Bac Tay Nguyen Chaper THEORETICAL BASIS AND RESEARCH METHODS OF SOIL GEOMORPHOLOGY IN BAC TAY NGUYEN 1.1 Theoretical basis of soil geomorphology 1.1.1 Science of soil geomorphology Each geomorphologic surface is determined by landform, age, parent rock/material and the process of forming landform Geomorphology accounts for three factors in the five soil forming factors Therefore, soil geomorphology is mainly focused on studying the relationship of these geomorphologic characteristics with soil and morphogenesis with the pedogenesis In the perspective of geomorphology and soil, J Tricart (1965) theo A.J Gerrard (1992) , soil geomorphology is to research the relationship of geomorphology and soil, the processes of formation and development It is to study the relationship of soil development with the forming factors Moreover, soil geomorphology is an important research method in re-establishing the ancient geographic environment (Gerrard, 1992; Birkeland, 1999) 1.1.2 Overview of researchs of soil geomorphology 1.1.2.1 Overview of researchs of soil geomorphology in foreign The relationship between relief and soil is researched very early in the late 19th century by Russian scientists, typically V.V Docuchaev who studied on determining soil related to relief in small territories N M Xibirtxev (1900) developed the theory of combine and structure and soil cover, and emphasized the terrain in creating soil combination X.X Neuxtruev (1910) raised the law of evolution and developed soil combinations corresponding to the terrain development stages of V Davis' diagram of terrain development During the surveys in eastern Africa, Milne (1935) discovered a sequence of soil types repeated in space related to relief change, and brought the theory of soil catena Clarke (1954) classified the soil catena into three categories: the drainage catena, the geological catena and mixed catana In the research of relationships of soil and topography, Boulaine (1966) and Aubert (1967) divided into soil chains where the soil components related to the forming relationship; the ranges of soil where the soil components have a very weak forming relationship Analyzing the relationship between morphogenesis and pedogenesis, J Tricart (1965, 1977) discovered that it was the transformation of the balances between these two processes that caused different types of soil sequences releated relief The author gived the concepts of truncated soil, buried soil, multi-phase soil Fridland VM (1972) studied and divided the soil structure into types of soil combination: soil combin, multi-temporal soil combin, soil complex Kilian (1972) used morphopedological method to build MP map with basic principles for general research G Bourgeon (1989) sketched MP landscapes directly from satellite images to create a reconnaissance soil map at a scale of 1: 1,000,000 for a wide area of peninsular India R Poss (1996) created a morphopedological map for northern Togo Franỗois Bộtard, Gộrard Bourgeon (2009) used the morphopedological method to analyze geomorphology and soil in northern Brazil 1.1.2.2 Overview of researchs of soil geomorphology in domestic Research on soil geomorphology in Vietnam is not much, has been mentioned since the 1990s and back, mainly typical research applications such as Dao Dinh Bac (1997, 1998), Nguyen Dinh Ky, Vu Ngoc Quang, Dao Dinh Bac, Bourgeon (1995-1999), Nguyen Van Dung (2014-2016) 1.1.3 Viewpoint of morphopedological landscape and its elements Morphopedological landscape is sequence of the soil types, groups on the surface unit of the terrain, is formed on the basis of the balance of morphogenesis and pedogenesis This concept coincides with catena, soil combime Moreover, the concept of morphopedological landscape is different from the concept of landscape that Vietnamese geographers still use Elements of soil cover in a morphopedological landscape include residual soil, truncated soil, (buried) deluvial soil, deposited soil They are arranged with slope rules from the summit, upper slope, lower slope and valley; they make up the corresponding morphopedological units 1.1.4 Factors affecting on landform and soil Morphopedological landscape reflects the relationship between terrain and soil in their formation, development; and in relations to the factors of parent rock/material, climate, organism, human activity and time 1.1.4.1 Parent rock/material: provides the original material that forms the terrain and soil It has different origin and petrographic composition that has different weathering rate and makes different characteristics of types of topography and soil 1.1.4.2 Time: determines the grade of development of terrain, soil and their relationship, thus affects on their characteristics 1.1.4.3 Climate, hydrology: Climate influences directly on topography and soil through rock weathering processes, morphogenesis, pedogenesis or indirect effects through impacts on fauna and flora systems Moreover, the characteristics and shapes of the hydrological network reflect the geological structure, characteristics and the dissection of terrain and soil 1.1.4.4 Creature: Flora plays a major role in transforming weathering layer into soil cover and creating fertility through the supply of organic residues, humus It affects on maintaining of stable conditions of heat, moisture, and water retention capacity; and maintaining the balance of morphogenesis and pedogenesis Moreover, vegetation type and growth rate are indicative of soil cover and a measure of soil productivity 1.1.4.5 Human activity: Humans have a profound influence on relation of geomorphology and soil through vegetation change, mechanical impact on terrain and soil by farming practices and land use; or the construction of civil works 1.1.5 Relationship between landform and soil in Bac Tay Nguyen On the slope surface, formation of a soil model of catena, reflecting the regular sequence of residual soil, truncated soil, buried soil and deposited soil, corresponding from the summit, upper slope, lower slope to valley The relationship between geomorphology and soil is presented in morphogenesis and pedogenesis, as follows: 1) Where there is strong morphogenesis, typically MP landscape of moutain has a strong erosion, and thin, truncated soil and buried soi 2) Where there is weak morphogenesis, weathering crust and soil cover are thick, typically MP landscape of plateau on basalt has a weak erosion and thick residual soil 3) Where there is moderate morphogenesis, typically MP landscape of sloping plateau, hill has moderate erosion and thick semi-residual, or residual soil In the plain, valleys, the formation and development of soil cover is based on the balance between sedimentation and the feralit, tropical podzol It is the basis for the formation of plain soil cantena that reflects alluvial sequence of yellow brown or gray soil, patchy color soil, deposited soil on the highest terraces to the lowest one The terrain distributes heat, humid conditions through the effects of elevation that forms altitude laws for geographic components including soil cover Elevation and situation of terrain redistributes of geochemical elements through the movement of flow and groundwater that changes on the soil characteristics In addition, direction of terrain affects directly or indirectly through factors that form soil 1.1.6 The forming process of MP landscapes in Bac Tay Nguyen 1.1.6.1 Pedogenesis: include feralit, laterit, sialit, decomposition and humification, tropical podzol, and gley 1.1.6.2 Morphogenesis: erosion, erosion of flow and sedimentation 1.2 Theoretical basis for the establishment of MP map 1.2.1 An overview of the classification system of MP landscape Typically the classification system of the French scientists and the classification system of the Australian scientists 1.2.2 Classification system of MP landscape for Bac Tay Nguyen The classification system is based on the origin of landform, especially the dynamics of its formation and the arrangement of soil elements with rules on the slope surface In this study, the author selected a three-grade classification system, including group, subgroup and type of MP landscape, with a scale of 1/250,000, of which: 1) MP group is formed on the basis of correlation between landform type and soil cover; 2) MP sub-group is formed on the basis of the correlation between morphogenesis with soil cover; 3) MP type is formed on the basis of the correlation between parent rock/material with soil cover in relation to the type and sub-type 1.2.3 Criteria for the classification of MP landscapes The classification of MP landscape at group grade is based on correlation between types of landform and soil cover The classification of landform is shown in Table 1.8 Table 1.8 Criteria for the classification landform Morphological characteristics No Landform Plain Semi-plain Low hill High hill Low plateau Medium plateau High plateau Low sloping plateau 10 Medium sloping plateau 11 High sloping plateau 12 13 14 16 Low mountain Medium mountain High mountain Valley Slope Elevation (m) < 30 < 50 5-150 5-150 < 50 Relief intensity (m) < 10 10 - 25 25 - 100 100 - 150 < 50 < 50 < 50 1000 - 2000 2000 5-150 50 - 150 500 -1000 5-15 50 - 150 1000 - 2000 5-15 50 - 150 > 2000 m 5-15 > 150 500 - 1000 > 15 > 150 1000 - 2000 > 15 > 150 > 2000