Synopsis of geography doctoral dissertation: Synthetic study the land cover in Thua Thien Hue province for development of sustainable agriculture and forestry

Objective: To establish the scientific basis on the synthetic study on land cover for sustainable development of agriculture and forestry in Thua Thien Hue.

MINISTRY OF EDUCATION

AND TRAINING

VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY

LE PHUC CHI LANG

SYNTHETIC STUDY OF LAND COVER IN THUA THIEN HUE PROVINCE FOR THE DEVELOPMENT OF SUSTAINABLE

AGRICULTURE AND FORESTRY

Major: Geographical and environmental resources

Code: 62 44 02 19

SYNOPSIS OF GEOGRAPHY DOCTORAL DISSERTATION

Hanoi - 2015

1 Dr Senior Research Fellow Nguyen Dinh Ky

2 Assoc Prof Dr Nguyen Tham

at day month year 2015

The dissertation can be found at:

- National Library of Vietnam

- Library of the Graduate University of Science and Technology

- Library of the Institute of Geography, Vietnam Academy of Science and Technology

- Information and Documentation Centre University of Pedagogy - University of Hue

HEADING

1 INTRODUCTION

Land cover is composed of many soils which have diffirent origins, and plays an very important role on agricultural and forestry production Under impact of formative and degrading factors, the characteristic of land cover was splited diversely and complexly thus it made diffirent values for land use types

Although the natural area of Thua Thien Hue province is not large, only 503,320.53 ha (area of soil is about 471,313.07 ha), but its land cover was impacted by many natural - economic - social factors over time thus splited complexly

The economic - social developmental direction to 2020 of Thua Thien Hue province affirmed the importance of agricultural and forestry production, defined which crops need to develop, and emphasized forest development activity to increase the area of forest In fact, there are many problems on agricultural and forestry production One of them is economic - social - environmental effectiveness decrease on using land, for example: the increase of soil degradation phenomenon; the quality of forest in Thua Thien Hue have not improved significantly yet; the status of unsystematic crops converting by local people

To protect the land cover and to carry out effectively the economic-social developmental direction, it is very necessary to sensibly collate land use types with land types in order to maximize the effect of agricultural and forestry production (manifest in stable, safe and effective) As a result, carrying out the

research “Synthetic study the land cover in Thua Thien Hue province for development of sustainable agriculture and forestry” in order to define the

actual state of the land cover and its potential for sustainable agricultural and

forestry development under changed natural - economic - social conditions, has

- Assess the suitability of the land cover for agricultural and forestry production types in Thua Thien Hue

- Propose reasonable land use solutions for sustainable agricultural and forestry development

3 RESEARCH SCALES

3.1 SPATIAL LIMITATION

Contents of Thesis are carried out inside the scope of Thua Thien Hue land, its natural area is about 503,320.53 ha

3.2 RESEARCH CONTENTS LIMITATION

The study focuses on the following main contents:

- Analyse the characteristic, formation, development and degradation law

of the land cover in Thua Thien Hue

- Determine the level of soil degradation which is the factor made risks for decreasing the ability of the land cover in Thua Thien Hue

- Evaluate the suitability of the land cover to determine land ability for land use types follow land units in order to propose reasonable land resource use solutions for sustainable agricultural and forestry development

- Thesis limitation is to study land use types for agricultural and forestry production

4 NEW CONTRIBUTION OF THE DISSERTATION

- Determine the specific characteristic of formation, development and degradation of the land cover in Thua Thien Hue follow geography view

- Establish Thua Thien Hue land units map (mention soil degradation factors), at rate of 1/100,000 for land suitability evaluation, beside set up the scientific base for proposing reasonable land resource use solutions for suctainable agricultural and forestry development in research site

5 DEFENDING THEORETICAL POINT

- Theoretical point 1: The land cover in Thua Thien Hue is very complex and

diversified that indicated its geography law of formation, development and degradation is from tropical highland to coastal

- Theoretical point 2: Determine the level of current soil degradation, evaluate

land suitability to supply scientific base in order to reasonable land cover use solutions for suctainable agricultural and forestry development in Thua Thien Hue

6 SCIENTIFIC AND PRATICAL SIGNIFICANCE OF THE DISSERTATION

be reference in study and teaching

7 OUTLOOK AND METHODOLOGY

7.1 Outlook: such points of view were applied as follow: systematic,

intergrated, domanial, ecological - economy, and sustainable development points of view

7.2 Methodology: method of documents collecting, analysis and processing,

method of geographical comparison, method of mapping, surveying method,

and method specialist

8 DOCUMENT BASE FOR CARRYING OUT THESIS

- System of Thua Thien Hue province maps used include: Soil map at the rate of 1/100,000; 1/200,000 geological map; 1/50,000 topographic map; and 1/100,000 land use map

-The results of basis investigation about natural condition and resources, soil testing results, soil profiles system taken from districts in Thua Thien Hue

- Surveying results

- Researches and published papers related to the thesis

- Others documents have been collected from projects which thesis author have participated, funded by Ministry of Education and Training, Hue University, Hue Pedagogical University

9 STRUCTURE OF THESIS

Structure of thesis, except the heading and conclusion, the main content was displayed inside 150 pages, contain 15 maps, 3 charts, 30 tables, 3

imagines and divided into 3 chapters

Chapter 1 Theory base of the synthetic study of land cover for agricultural and

forestry development in Thua Thien Hue

Chapter 2 The specific geographic properties of Thua Thien Hue land cover

formation and degradation

Chapter 3 Synthetic assessment on edaphic overlay in Thua Thien Hue

province for the sustainable development of agriculture and forestry

Chapter 1 THEORY BASE OF THE SYNTHETIC STUDY OF LAND COVER FOR AGRICULTURAL AND FORESTRY DEVELOPMENT IN

THUA THIEN HUE

1.1 Conceptions: The thesis have studied related conceptions as soil, land

cover, land resource, soil environment, land units, land use type, land use status, soil and land degradation, land evaluation, sustainable agricultural and forestry development… that are base for solving problems on next chapters

1.2 Overview related researches in the world and Vietnam

1.2.1 Soil classification researches

In the world: Eventhough there are many engineering classification system

for soils in the world, but FAO - UNESCO soil classification system was applied widely due to use simple nomenclature system and to be a quantiative classification system

In Vietnam: The land classification system in Vietnam, mostly

the classification arises soils, this classification is based on aggregate indicators include the formed factors, formation processes of soil and soil properties.For international integration, at present, Vietnam Union of Soil Sciences corresponding converted land classification system of Vietnam to the land classification system of FAO - UNESCO

1.2.2.Soil degradation researches

Study soil degradation was attached special importance to in the world and Vietnam as well, and focused on contents as methods of soil degradation evaluation and mapping, thenceforward release warnings about soil degradation risk, solutions, and action plans to prevent soil degradation from happening in

regions

1.2.3 Land evaluation and classification researches

Both researches in the world and Vietnam follow these trends:

♦ Determine land is an area contain natural environmental factors which effect

on land use The basis units for land evaluation are land units; ♦ Pay attention to natural factors which impact on soil quality, especially to long-time and hard-to-repair limitation factors; ♦ Land evaluation connect closely to use purpose include: land quality, quantity and economy evaluation; ♦ The main evaluation methods are mark, calculate the percentage, and land suitability analysis for each land uses

These are most suitable research trend for land evaluation to build the land suitability maps for crops However, the FAO land evaluation procedure indicated that determining targets, building and overlapping maps to define land units at diffirent regions could not be united Each territory need have itself a targets system with rules and standards differ with anothers On the others hand, adding soil degradation status into the targets system will increase the accuracy

of building land suitability maps for crops

1.2.4 Researches about natural condition and domain reasonable use happened in Thua Thien Hue

There are many researches about geology, topography, climate, hydrology, biology and environment, soil degradation, land evaluation for agricultural and forestry development happened in Thua Thien Hue However, there is not any research about land suitability evaluation for agricultural and forestry land use types in the whole Thua Thien Hue province as well as proposing the direction of sustainable agricultural and forestry development in the relationship with soil degradation status

1.3 Outlook and methodology on soil degradation and land suitability analysis serve agricultural and forestry development in Thua Thien Hue

1.3.1 Outlook on evaluation: base on soil formation, intergrated and

sustainable land use views, determine soil is a dependent natural individual which formed and impacted deeply by factors as parents rock, topography, climate, hydrology, biology and human being The interaction between factors leaded to formation of specific characteristics in soil formation and degradation

as well as of each land type or region in Thua Thien Hue province This is a factor contribute to spilting of land units value Thenceforward, provide base for choosing and ranking targets for sustainable land suitablility analysis

1.3.2 Method of evaluation

- Method of soil degradation status evaluation: to evaluate soil degradation

status, the thesis used methods of soil profiles comparison; plant indicators for soil degradation; define limitation factors in soil physical and chemical applying VN-2008 standard Beside, inherited soil formation and degradation researches carried out by Nguyen Van Cu & nnk, Nguyen Dinh Ky, Nguyen Anh Hoanh that ranked soil degradation status in TTH into 3 level as follow: Not or slightly (H1); medium (H2) and seriously (H3)

- Method of land suitability analysis and ranking:

To evaluate land suitability, the thesis applied D.L Armand method to land suitability evaluation for agricultutral and forestry development in Thua Thien Hue The problem is:

In there: M0: evaluated marks of land units; a1, a2, a3…an: marks of 1st,

2nd …nth; n: the amount of evaluation targets

After refered FAO ranking procedures (Dent D và Young A) (1981); Young A (1989) and others, the thesis used 4 ranking levels, include: S1 (Extremely suitable), S2 (Suitable), S3 (Slightly suitable) and N (not suitable)

The way of ranking applied math method and range caculating formula ∆D which is suitable for specific condition of research area The formula is:

In there: ∆D: the value of point range of each rank; Dmax: the value of highest evaluated mark; Dmin: the value of lowest evaluated mark; M: the amount of evaluated levels

CONCLUSION OF CHAPTER 1

1 The thesis overviewed selectively documents, and researches related to intergrated land cover evaluation for sustainable agricultural and forestry development in the world, Vietnam and Thua Thien Hue Beside, applied main viewpoints in land evaluation such as: soil formation, intergrated and sustainable land use viewpoints

2 The two main content of the thesis are soil degradation status analysis and FAO land suitability evaluation Land unit are basis unit which selected to evaluate land potential as well as to orient using land in research area base on

soil degradation status

3 Methods of soil profiles comparison; plant indicators for soil degradation; define limitation factors in soil physical and chemical applied to evaluate soil degradation status, and D.L Armand method, math method and

range caculating formula ∆D used for land suitability evaluation

Chapter 2 SPECIFIC GEOGRAPHICAL FORMATION AND

DEGRADATION OF LAND COVER CHARACTERISTIC IN THUA

THIEN HUE 2.1 Formation and degradation factors of Thua Thien Hue land cover

2.1.1 Location: Thua Thien Hue province locate at coordinate of 15059’30”

N-16044’30” N and 107000’56” E đến 108012’57” E; it borders Quang Tri Province to the north and Danang to the south, Laos to the west and the East Sea to the east This location led to appearance of tropical monsoon climate characteristics in formation, development and degradation of TTH soil, and to complex splitting of the land cover Although TTH area is not large, but its land cover is very diverse For example: Arenosols, Salic Fluvisols, Thionic Fluvisols

in the coastal; Ferralic Acrisols in the hills and Humic Ferrasols in the mountainous

2.1.2 Geological condition and parent rocks

- Thua Thien Hue province is inside two structural zones, A Vuong and Long Dai, which belonging to Vietnam - Laos Eugeosynclinal folded area that make a diffirence in topography between North, North - East, East regions and West, South-West regions within the province, thenceforth impact on other soil formation and splitting factors as climate, hydrology, biology…

- In Thua Thien Hue, the common parent rocks are acid-neutral intrusive igneous rocks, continental sedimentary rocks, early Paleozoic metamorphic rocks which belong to A Vuong - Long Dai Formation Besides, there are river, sea, river - sea, lagoon - sea sediment and Kainozoic sediment which distribute in the coastal and along the rivers The bed rocks and parent materials quoted above established the basis characteristic of Thua Thien Hue soil, and the diffirence between soils as follow: ♦ Soils formed from acid igneous rock (Granite rock) are loamy sand and sandy loam textured; ♦ Soils formed from clay stone and metamorphic rock are clay loam and clay textured with quite deep layer; ♦ Soils formed from sand stone are loamy sand and sandy loam textured with slightly deep layer but its structure are unconnected as a result

have high risk of erosion and leaching; ♦ Soils formed from sediment have high fertility and quite deep layer; ♦ Soils formed from bog-sea sediment contain many risk for crops

Because of form from diffirent bed rock hence erosive resistibility of soils are diffirent, for example, soils formed from sand stone and acid igneous rock… are easy for erosion and leaching On the other hand, soils formed from clay stone, neutral igneous rock, sediment have higher erosive resistibility

2.1.3 Topography: topography of Thua Thien Hue separated into mountainous

and hill (43.5%), plain and coastal (35%) The terrain get lower in the east and it is along the direction of North West - South East parallel

The diversity of Thua Thien Hue terrain impacted deeply on soil formation through redistribution of material and energy As a result, formed soils which splited under the impact of altitude and condition of each region, and differ from each other in soil degradation process, as follow: Humic Ferrasols, Haplic Acrisols and Ferralic Acrisols (easy to happen erosion and leaching); Fluvisols, Salic Fluvisols, Thionic Fluvisols, Gleyic Fluvisols and Arenosols (easy for land slide, soil pollution… happen)

2.1.4 Climate: Thua Thien Hue climate is similar to central Vietnam in general: a tropical monsoon climate, it is splitted complexly and diversely, and many natural disasters happened annually The specific characteristics of TTH climate are high temperatures (the annual average is 24 - 250C), heavy precipitation (from 2,700mm to over 3,600mm) which concentrate on rain season that occupy 75% annual precipitation The relation between temperatures and humidity which splitted following temporal and spatial have serious effect on splitting of land cover formation, degradation factors in research area As a result, establishing map of bio - climate in Thua Thien Hue indicated that there are 7 kinds of bio-climates This is one of bases made splitting of soil and land in research area Indeed, the annual average high temperatures combine with huge temperatures amplitude support to tropical wheathering happen, and mineralization and physical-chemical wheathering take place fiercely Besides, heavy precipitation which concentrate on rain season, and rain usually fall heavily (especially in rainstorm season) made soil erosion and leaching happen seriously in the highland, and land slide, flooding, soil burying take place in the mountain foots, valley and plains

2.1.5 Hydrology: TTH has very diverse hydrologic system include rivers, streams,

lakes, lagoon The rivers system which flow to Tam Giang-Cau hai lagoons system

before to the sea, is quite dense Most rivers has small valley but they flow fast as a result their sediments are normally coarse, rich in SiO2 but poor in nutrient In the flooding season, the speed of flows are very high thus the sediments at flooded places are coarse, the rate of fine particles are low On the other hand, in the dry season, the level of rivers get lowest that decrese the sediments consolidation as well as make salinization happen

2.1.6 Flora: the plant in Thua Thien Hue are extremely diverse and rich (area

without plant is rare) and divided into groups as follow: Natural floristic

composition include evergreen broad leaf tropical and subtropical rainforest contain the characteristics of rich forest but occupy an insignificant area; mangrove forest in the coastal; grassland and shrubland; aquarium

communities Cultivated floristic composition include cultivated forest and

agricultural crops TTHue province has large area covered by poor forest, restoration forest, tree-plot of which covering level are extremely low (20%-50%), and these forests do not play in surface water regulation; while the rate of area of forest of which covering level are from 70-90% occupy 16,21% As a result, impact heavily on soil fertility and degradation status

2.1.7 Human being activities in land using and exploitation: Human being

activities which impact heavily on TTHue soil formation and degradation are: agricultural and forestry production, cultivation method (especially of Ethnic groups), urbanization process Eventhough agricultural and forestry share got lower but absolute value still increased that mean the impact of human being

activities on land lead to deep change in land use structure and soil properties 2.2 Soil formations in Thua Thien Hue

The main processes of soil formation in TTH include 7 processes as follow:

♦ Mineralization and humus formation which happen powerfully due to TTH advantageous conditions such as belong to wet tropical zone, level of plant coverage is high; ♦ Gleyic soil formation process is popular in Phong Dien, Phu Loc and Quang Dien districts…; ♦ Sediment consolidation process happen annually along with river and stream system, and in valleys inside the province; ♦ Saline soil formation take place in coastal river mouths which distributed mainly

in Phong Dien, Phu Loc and Quang Dien districts ; ♦ Thionic Fluvisols formation process is happening on low - lying land in the coastal of Phong Dien, Phu Loc and Quang Dien districts;♦ Feralization in the highland; ♦ Soil erosion and nutrient leaching happen powerfully in slope land belong to Phu Loc, Nam Đông, Aluoi districts

2.3 Thua Thien Hue soil characteristic

The land cover in Thua Thien Hue are diverse and plentiful, include 10 soil groups contain 23 soil types In there, area of soil formed under impact of sediment consolidation is 98,884.47 ha, occupy 19.64% natural area Meanwhile, area of soil formed from parent material is 372,428.60ha, occupy 74% natural area

Table 2.10 Soil classification in Thua Thien Hue province

No Land under the

Vietnamese name

Land under FAO-UNESCO name

Area (ha)

% Natural area

I Sandy soil group Arenosols 47,748.6

4 Medium soil salinity Molli Solochaks 7,296.68 1.45

III Acidic soil group Thionic

Fluvisols 5,193.80 1.03

5 Alkaline soil operate deep,

medium salty

Thionic Fluvisols

IV Alluvial soil group Fluvisols 37,518.6

7

7.45

6 Alluvial soil is accreted annual Dystric Fluvisols 2,546.47 0.51

7 Alluvial soil without accreted

annual

Dystric Fluvisols 17,928.7

0

3.56

9 Alluvial soil with red patchy

yellow

Plinthic

10 Alluvial soils along streams Dystric Fluvisols 1,595.54 0.32

11 Alluvial soil covered in sand Areni Dystric

Fluvisols

13 Gray soil on magma acid Ferralic Acrisols 201.28 0.04

VII Yellowish red soil group Acrisols 352,880.5

Soil formed under impact of sediment consolidation 98,884.47 19.64