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 The study is accomplished at: ……………………………………………………………………………………………………… Scientific instructor: Dr Senior Research Fellow Nguyen Dinh Ky Assoc Prof Dr Nguyen Tham MỞ ĐẦU Reviewer 1: Reviewer 2: Reviewer 3: The dissertation is protected before the Graduate University Council at …………………………………………………………………………………… 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 MỞ ĐẦU University of Hue HEADING 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 (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 great significance OBJECTIVE AND DUTY 2.1 Objective To establish the scientific basis on the synthetic study on land cover for sustainable development of agriculture and forestry in Thua Thien Hue 2.2 Duty - Selected overview of documents relative to thesis to build theory base for intergrated study the land cover use for sustainable agricultural and forestry development - Study the geographic properties of formation and degradation of the land cover in Thua Thien Hue - Clarify the current status of soil degradation in Thua Thien Hue as one of preferential base in land suitablility analysis for agricultural and forestry production arrangement - 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 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 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 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 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 SCIENTIFIC AND PRATICAL SIGNIFICANCE OF THE DISSERTATION 6.1 Scientific significance - The result will clarify the procedure of research on law of soil formation and degradation… that formed land units in Thua Thien Hue - The thesis is going to contribute to complete theory base for land suitability evaluation, and to enrich the research direction in appicational geography for land use planning 6.2 Practical significance - The thesis was updated and analysed new valueable source of land data for reasonable land use planning for agricultural and forestry development - The thesis will be very good document for local policy planner in establishing the economic development strategy, domain use planning as well as be reference in study and teaching 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 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 STRUCTURE OF THESIS Structure of thesis, except the heading and conclusion, the main content was displayed inside 150 pages, contain 15 maps, charts, 30 tables, imagines and divided into chapters Chapter Theory base of the synthetic study of land cover for agricultural and forestry development in Thua Thien Hue Chapter The specific geographic properties of Thua Thien Hue land cover formation and degradation Chapter Synthetic assessment on edaphic overlay in Thua Thien Hue province for the sustainable development of agriculture and forestry Chapter 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-torepair 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 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: n a1 a2 a3 an M0 = 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 Young A) (1981); Young A (1989) and others, the thesis used 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: ∆D = Dmax - Dmin M 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 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 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 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 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” N16044’30” 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 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 VII Yellowish red soil group Acrisols 14 Yellow red soil on clay stone Ferralic Acrisols 15 Yellow red clay soil on metamorphic rocks 16 Red yellow soil on magma acid Ferralic Acrisols 17 Light yellow soil on sandstone 18 Brown yellow soil on ancient alluvial gold 19 Yellow red soil changes due to rice cultivation VII Humus yellow red group I 20 Humus red yellow on metamorphic 21 Humus red yellow on acid magma IX Soil valley by the steep valley Haplic Acrisols Ferralic Acrisols Ferralic Acrisols Plinthic Acrisols 352,880.5 81,007.8 84,371.6 136,187 40,539.9 10,420.1 70.11 16.10 16.76 27.06 8.05 2.07 353.12 0.07 14,359.4 2.85 4,273.48 0.85 10,085.9 2.00 543.71 0.11 543.71 0.11 4,987.29 4,987.29 98,884.47 404,436.6 Total area 471,313.0 Rivers, streams, lakes, marshes 31,288.7 Rock mountain 718.70 Total natural area 503,320.5 0.99 0.99 19.64 74.00 capacitor 22 Soil valley by the steep valley capacitor Humic Acrisols Humic Acrisols Humic Acrisols Gleysols Dystric Gleysols X Soil erosion Leptosols 23 Soil erosion Leptosols Soil formed under impact of sediment consolidation Soil formed from parent material 93.64 6.22 0.14 100 CONCLUSION OF CHAPTER Soil formation and degradation factors in TTH province manifest the specific characteristics of wet tropical climate and are splitted clearly following spatial and temporal These are results of intergrated effect of factors: TTH locate inside the tropics which is exchanging zone of air blocks where happen the interaction between ocean and continent; Its geological structure is diverse; Its topography separate into plain, coastal, hill and mountainous; its climate is hot, wet, high precipitation and splitted deeply to two seasons and bioclimatic types; river system is short, slope, few sediment content, and its water regulations changed clearly by season; Plant are plentiful but mainly poor forest, restorating forest, shrubland of which the covering level are very low; The impact of human being activities on soil formation and degradation are significant due to TTH is under influence of Vietnam war, urbanization, strongly land using and exploiting, and Ethnic groups There are main soil formation processes in TTH include: Mineralization and humus formation; Gleyic soil formation process; Sediment consolidation process; Saline soil formation; Thionic Fluvisols formation process; Feralization Soil erosion and nutrient leaching The land cover in Thua Thien Hue are diverse in types and complex in distribution, include 10 soil groups contain 23 soil types Chapter SYNTHETIC ASSESSMENT ON LAND COVER IN THUA THIEN HUE PROVINCE FOR THE SUSTAINABLE DEVELOPMENT OF AGRICULTURE AND FORESTRY For intergrated land cover research, the main factors selected include soil type, soil texture, soil slope, soil depth, soil degradation status The splitting of factors are showed in separation into land units 3.1 Soil degradation status in Thua Thien Hue 3.1.1 Specific soil degradation processes in geographic areas: ■ Mountainous: including main soil types as Fa, Fj, Fs, Fq, and Ha Besides, contain a small area of Hj, Fp and Py Soil Slope in most of the mountainous is over 150; soil textures are mainly loamy sand, sandy loam, and loam; soil is low in depth As a result, soil degradation processes are manily erosion, land slide, especially in rain season; ■ Hill: the popular soils are Fs, Fa, Fq on which soil degradation processes happen are nutrient leaching, soil erosion, laterization, and soil pollution happen on land near the plain; ■ Plain, coastal: including soils such as C, P, Pg, Pb, M, S, D, Fa In there, Arenosols occupy largest area on which usually happen soil eroded, river and sea bank slide, salinization, aluminous land formation, gleyic soil formation … wind erosion… 3.1.2 Soil degradation status in Thua Thien Hue: soil chemical (soil solution pH, organic matter content, N% - P2O5% - K2O%; P2O5 - K2O valuable, CEC), physical (soil depth, soil texture) characteristics and plant indicator analysis, comparison determined level of soil degradation in TTH In there, level of non or slightly degrading (H1) is largest (237,456.15ha) occupy 47.18% natural area Land use status is natural forest, and got human being impacts distribute in Aluoi, Nam Dong districts and at areas along Huong, Bo river… ; Level of average degrading (H2) occupy 117,307.02ha corresponding with 23.31% natural area, distribute mainly in Phong Dien, Aluoi, Huong Tra, Nam Dong, Phu Loc districts on which land use status are annual crops, shrub land and scratch garden; Level of serious degrading (H3) occupy 116,549.9ha corresponding with 23.15% natural area distribute at sand dune, sand-plot and on Lithic leptosols in Phong Dien, Quang Dien, Phu Loc… Land use status on almost area are rice fields, unuse land, tree and shrub land, new cultivated forest 3.2 Land suitabilty evaluation for agricultural and forestry development in Thua Thien Hue 3.2.1 Selecting and ranking targets for building land units map Base on requests, general principle as well as specific properties of research area, ecological demand of crops to select quantity of and rank targets sensibly The targets used for land suitability evaluation in Thua Thien Hue include ones as follow: soil type, slope, depth, texture, topographic altitude, humus content, bioclimatic, water drainage and soil degradation status The targets of land use status and special wheather… ranged into referential group, and mentioned specifically at proposal of orientation of agricultural and forestry development in TTH Each crops group use specific evaluation Table 3.9 Targets and ranking targets for building land units map of Thua Thien Hue province No Targets Ranking Soil White sand dunes (Cc) type Soil sea sand (C) High soil salinity (Mn) Medium soil salinity (M) Alkaline soil operate deep, medium salty (Sj2M) Alluvial soil is accreted annual (Pb) Alluvial soil without accreted annual (P) Alluvial soil Gley (Pg) Alluvial soil with red patchy yellow (Pf) 10 Alluvial soils along streams No Targets Texture Ranking Clay loam Loam Sandy loam Loamy sand Sand > 3% Humus content 2-3% 1-2% < 1% Topographic < 50 m Slope Depth (Py) 11 Alluvial soil covered in sand (P/C) 12 Swamp soil (J) 13 Gray soil on magma acid (Ha) 14 Yellow red soil on clay stone (Fs) 15 Yellow red soil on clay metamorphic rocks (Fj) 16 Red yellow soil on magma acid (Fa) 17 Light yellow soil on sandstone (Fq) 18 Brown yellow soil on ancient alluvial (Fp) 19 Yellow red soil changed due to rice cultivation (Fl) 20 Humus red yellow on metamorphic (Hj) 21 Humus red yellow on acid magma (Fa) 22 Soil valley by the steep valley capacitor (D) 23 Soil erosion (E) altitude < 80 - 150 15 - 250 > 250 > 100cm 70 - 100cm 50 - 70cm 700 m Bioclimatic IA1a, IA1b IIA1a, IIA1b IIIA2a IVA3a IVA3a* Water drainage Good drainage Relatively good drainage Difficult for drainage Very difficult for drainage Figure Figure2 Figure3 Thua Thien Hue land units map was built by using mono-maps overlapping method, thenceforth combined characteristics of all areas in order to determine the amount of land unit Result of combination determined 130 land units, in there 111th land unit is largest in area corresponding with an area of 35,423.23ha, the smallest one is 49th which occupy an area of 100.88ha 3.2.3 Land units suitability evaluation and classification for agricultural and forestry development 3.2.3.1 Selecting agricultural and forestry land use types for evaluated targets Agricultural land use types including: annual crops (groundnut, beans, sesame), fruit-tree (Thanh Tra pomelo), industrial crops (rubber tree); forestry land use types including: Acacia were selected to evaluate 3.2.3.2 Land unit suitability evaluation and classification for agricultural and forestry developmen Ecological demand of crops for evaluated according to targets system as follow Table 3.11 Ecological demand of crops Crops Targets Soil type Slope Depth Annual crops (groundnut, beans, sesame), Extremely suitable (S1) C, Pb 70cm Texture Sandy loam, loamy sand Humus content - 2% Topographic 150 50 700m IIA1a, IIIA2a, IVA3a* IIA1b IVA3a Relatively Difficult Very difficult good Average Serious - Soil type Slope Depth Texture Thanh Tra Humus content pomelo Bioclimatic Water drainage Soil degradation status Soil type Slope Depth Rubber tree P, Pf, Py, Fs, Fa, Fq, Extant D Fp 0 0 250 >100cm 7050-70cm 3%, -3% - 2% 3% 250