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: 9 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: 1 Ph.D Nguyen Đinh Ky

2 Assoc Prof Ph.D Nguyen Dich Dy

Thesis can be found in

- The library of the Graduate University of Science and Technology

- Vietnam’s National Library

INTRODUCTION

1 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, soil-organisms 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

- 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

4 Research area and object

- Research area: Bac Tay Nguyen, including Kon Tum and Gia Lai

- Research object: geomorphology, soil in Bac Tay Nguyen region

5 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

6 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

7 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

8 The structure of the thesis

Apart from the introduction, the conclusions and recommendations, reference and appendix, the thesis consists of 3 chapters:

Chaper 1 Theoretical basis and research methods of soil geomorphology in Bac Tay Nguyen

Chaper 2 Conditions of formation and characteristics of morphopedological landscapes in Bac Tay Nguyen

Chaper 3 Assessment of morphopedological landscapes for planning and using land sustainably in Bac Tay Nguyen

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 6 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

François Bétard, Gérard 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, sub-group 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

10 Medium sloping plateau 5-150 50 - 150 1000 - 2000

1.2.4 Procedure of the establishment of morphopedological map

Establishing the morphopedological map of Bac Tay Nguyen is done according to the procedure of Figure 1.4

Figure 1.4 Procedure of the establishment of MP map

1.3 MP basis for planning and using land sustainably

1.3.1 Relationship morphopedological landscape and planning, using land sustainably: land use and vegetation play an important

role in maintaining the balance of morphogenesis and pedogenesis This balance is prone to morphogenesis; increased natural disasters cause land degradation and unsustainable ecosystems This balance

is prone to pedogenesis; mitigated natural disaster that lead to stable

soil fertility for high biological productivity, sustainable ecosystem

1.3.2 Assessment of MP landscape for planning, using land sustainably

Assessment of morphopedological landscape is the consideration

of the characteristics of the MP landscape that are relevant to the ecological needs of the types of land use; and the consideration whether the current land use is appropriate or not to change the plan of land use in order to achieve the goal of sustainable development

In the appropriate ranking of morphopedological landscape, PhD student uses the most restrictive principle, if it has superior factor that is the maximum limit, it is ranked by the level of the factor

1.3.3 Tolerance of soil erosion: In this study, value of 5

tons/ha/year is used for tolerance of soil erosion

1.3.4 Agroforestry: is a spatial model of sustainable production for

the hills and plateaus

1.3.5 Territorial, spatial organization: in this study, it is based on

morphopedological landscape that show the relationship between soil, terrain and the forming spatial factors The arrangement of land use types on different scales is based on various grades of MP landscape from the high to low in order to obtain the most high

society of economy, society and environment

1.3.6 Land use planning: In the morphopedological approach, land

use planning is a process of assessing potential MP landscapes, making decisions, and taking action in dividing the MP landscapes

for use needs to provide the most profitable, and secure future needs

1.4 Viewpoint and methodology

1.4.1 Viewpoint: perspective of integrate and system, historical

perspective, ecological perspective, sustainable development perspective and land degradation perspectives

1.4.2 Methodology: morphopedological methods, field survey

methods, method of mapping, remote sensing and GIS, method of quantitive assessment of soil erosion and sample analysis methods

1.5 The research steps of the thesis

Figure 1.5 Diagram of steps to implement the project

Chapter 2 FEATURES OF MP LANDSCAPES AND THEIR FORMING CONDITIONS IN BAC TAY NGUYEN

2.1 Forming conditions of MP landscapes in Bac Tay Nguyen

2.1.1 Geographical location

Bac Tay Nguyen region is located in the coordinates from

13055'10" to 14°36'30"N and from 107°27'23" to 108°54'40"E covers an area of 2.522.653 hectares, includes two provinces: Kon Tum and Gia Lai It stretches north-south, small in the north, large in the north The mountain in the east causes the foehn that make up the difference between the climate of the region and Duyen Hai Nam Trung Bo

2.1.2 Geological conditions

BTN has a variety of parent rock/material from Quaternary formation to Ackeozoi formation, a variety of origin from sedimentary, metamorphism to intrusive igneous magma, extrusive igneous magma They are complicated by the process of tectonics and denudation Based on the composition and the origin of geology,

it is divided into 8 main groups of parent rock/material

2.1.3 Conditions of landform

Bac Tay Nguyen is a system of mountain, sloping plateaus high valleys and plains The alpine system is in the east and gradually descends to the west It has a bow shape, the convexity is facing east, and embraces the plateaus and plains in the west

2.1.4 Conditions of climate

The area is also affected by tropical monsoon climate, and has the nature of cool plateau-climate Annual average temperatures range from 170C to 270C Annual average rainfall ranges from 1,200 to 2,800 mm Due to the influence of the terrain, the climate changes markedly in the direction of north-south There are three types of climate: the tropical climate of the high mountains in the north, gradually moving into the tropical plateau-climate, and the semi-arid tropical climate in the south

2.1.5 Conditions of hydrograph

The network of rivers and streams are relatively developed, its erosion in this place is strong, water divides is very complex The river network of the area is closely related to geological structure and fault systems It has large river systems such as Song Ba, Se San, Po

Ko and Dak Bla

2.1.6 Vegetation characteristics

The vegetation covers the following types: broad-leaved evergreen forest; broad-leaved deciduous forest; coniferous forest; needle, broadleaf-mixed forest; bamboo, broadleaf-mixed forest; bamboo forest; plantation forest; shrub; shifting cultivation; wet rice; and perennial crops

2.1.7 Human activities

The increase in mechanical population over the years has put pressure on the resources and environment - the large need to use land for socio-economic development Most of the area has been put into use, of which the agricultural land group is 2,268,822 ha, accounting for 89.94% of the natural area, including agricultural production land is 1,066,374 ha and forest land is 1,199,881 ha; Non-agricultural land is 147,385 ha, accounting for 5.84% of the natural area; and unused land is 102,941ha, accounting for 4.08% of the land area

2.1.8 Characteristics of soil cover

It has 9 soil groups of 24 soil types which show the interrelation

of the zonal and azonal laws, closely related to the formation conditions The zonal soil group includes the reddish-yellow feralite soil, the reddish-brown feralite soil, and the semi-arid gray soil that characterizes the arid climate; Alluvial soil, gley soil, black soil, thin soil shows the azonal law; and red feralite humus soil and reddish brown feralit soil show the high altitude law

2.2 Features of MP landscapes in soil Bac Tay Nguyen

Based on the relationship of geomorphology and soil, their the forming factors, selecting the classification system suitable for the study area, the PhD student conducted MP mapping at a scale of 1/250,000 with the classification criteria system and mapping process established Nature characteristics in Bac Tay Nguyen are shown in 12 groups and 39 types of MP landscapes In that the relationship between geomorphology and soil are reflected

2.2.1 MP landscape of medium mountain

It is distributed mainly in the Ngoc Linh mountain range Due to the dominant denudation process, the high elevation that corresponds

to the landform of medium mountain are soil combine of humus feralite It includes two main elements: thin truncated soil on upper slope and deluvial soil (thicker and more humus) on lower slope They satify Umbric Leptosols or Umbric Cambisols Moreover,

deluvial soil element on more dissected mountain accounts for a bigger proportion than that on less dissected one, and soil cover changes with magma acid and metamorphic rock, these form 4 MP landscape types: KJ, KIJ, KA và KIA

2.2.2 MP landscape of medium sloping plateau

It is distributed in Kon Ha Nung and Kon Plong Sloping plateau

is the result of the peneplanation in ancient geography, has thick weathering cover and strong pedogenesis; Moreover, due to high elevation, that is advantageous to form humus semi-residual and residual soil with profile development such as: humus reddish-yellow feralite soil that satisfy Humic Acrisols or Humic Ferralsols Most of the landform is dissected, has the structure of hills and hollows, and formed on magma acid and metamorphic rock, soil cover is various with that conditions, reflected in two MP landscape of OHJ and OHA

2.2.3 MP landscape of medium plateau on basalt (OZ)

It is distributed in Kon Plong and Kon Ha Nung, formed on basalt rocks with Neogene age, has a thorough weathering process for thick weathering layer and soil cover The soil is reddish brown, granular structure, texture of medium loan Corresponding to medium basalt plateau is a residual soil combine of reddish brown However, medium plateau is divided into the summit surface with a height of 1100-1400 m, dissected shallowly; upper surface with the height of 900-1100 m dissected deeply; and the lower surface at a height of 600-900 m, dissected shallowly; soil cover vary with those surfaces, presented in the MP landscape of OZ1, OZ2, OZ3

2.2.4 MP landscape of low mountain

It is distributed in Sa Thay and Mang Yang This MP landscape has the dominant process of erosion and continuous rejuvenation so the soil is often thin, has much rock fragments Corresponding to low mountain is reddish-yellow soil combine of feralite, which includes two main elements: thin truncated soil on upper slope, thicker deluvial soil on lower slope They satisfy Leptosols or Cambisols Deluvial soil element on more dissected mountain accounts for a bigger proportion than that on less dissected one; moreover, soil cover changes with forming rock, present in 3 MP landscape of NIJ,

NJ and NA

2.2.5 MP landscape of low sloping plateau

This MP landscape is distributed from Ngoc Hoi to Sa Thay It is formed the ancient landform, has thorough weathering process and high pedogenesis, which lead to thick weathering crust and soil cover Corresponding to stable environment of sloping plateau in long time is semi-residual and residual soil with profile development such as: yellowish-red soil combine of feralite, satisfying Acrisols; and reddish-brown soil combine of feralite, satisfying Ferralsols

In heavy rain conditions, most of sloping plateau is much dissected, has structure hills and hollows Soil cover changes with the structure, present in 4 landscape of CHJ, CRJ, CHA, CRA

2.2.6 MP landscape of low plateau (CZ)

MP landscape of CZ is distributed widely Gia Lai province and Kon Tum town Due to the characteristics of basalt, the weathering process is thorough, so weathering crust and soil cover is thick, relief

is smooth That is favorable conditions for forming groundwater rich

in Fe2+, Al3+ Fluctuations of groundwater, capillary process, influence of altitude laws create a change of lateritic process in the position of plateau surfaces: the fairly flat summit surface with a height of 700-850 m, the deeply dissected upper surface with a height of 500-800 m, the dissected lower surface that is a height of 300-600m has laterite, the foot of plateau that is a height of 300-350m has laterite Moreover, contact plateau of basalt is thin Residual soil vary accordingly, is presented in 7 MP landscape of CZ11, CZ12, CZ21, CZ22, CZ31, CZ32, CZ4

2.2.7 MP landscape of high plain and valley

It is distributed from Ngoc Hoi to Kon Tum town This MP landscape is formed on accumulation products of Po Ko river system The characteristics of the soil cover are varied according to the river terrain and the origin of deposited sediment, presented in two MP landscape of TP and Tt

2.2.8 MP landscape of hill

Most of hill is formed by pediment Corresponding to medium pediment hill is soil combine of truncated soil, deluvial soil Most of the relief is dissected and has structure hills and small hollows or large hollows Soil cover changes corresponding to the structure, is presented in MP landscape of DRA and DHA

2.2.9 MP landscape of semi-arid low mountain