MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY - NGUYEN THI THUY STUDY ON GEOGRAPHIC BASIS IN EXPLOITING AND USING LAND FOR SUSTAINABLE PLANNING IN DA LAT CITY AND ITS VICINITIES - LAM DONG PROVINCE Major: Geography of Resource and Environment Code: 44 02 20 THESIS SUMMARY FOR GEOGRAPHY DOCTOR Hà Nội - 2019 The thesis was completed in: Graduate University of Science and TechnologyVietnam Academy of Science and Technology Science instructor 1: Ph.D Nguyen Dinh Ky Science instructor 2: Prof Ph.D Sc Hoang Van Huay Reviewer 1: ……………………………………………… Reviewer 2: ……………………………………………… Reviewer 3: ……………………………………………… The thesis will be defended in front of the Institute's doctoral thesis evaluation council, meeting at the Graduate University of Science and Technology - Vietnam Academy of Science and Technology at …… hour ……, date …… month …… year 201 …… Thesis can be found in: - The Library of Graduate University of Science and Technology - Vietnam’s National Library INTRODUCTION The necessity of the thesis Urbanization is an inevitable trend in the history of social development Urban population has now reached 50% of the total world’s population, with rapid urbanization, especially in developing countries Urban concentration has brought greater economic scales to cities and territories, but its downside can lead to negative impacts on resource degradation and environmental pollution To address these challenges, various approaches in urban and territorial planning have been studied and implemented Located on Lang Biang Plateau, with an average altitude of 1,500m above sea level, Da Lat City is the first-class city of Lam Dong province This is a famous vacation and tourism place of Vietnam However, over 120 years of formation and development, today's landscape of Da Lat has had a great change The city's space has been constantly expanding in terms of residential land and agricultural production land, narrowing forest land, increasing the density of housing and agricultural production works, concentrating in the central area, which have changed the landscape structure and polluted the city It can be seen that the changes in the land use exploitation structure are the direct reasons that cause Da Lat to be in danger of losing the "proportion of space" in the landscape structure and the decline of the entire ecosystem In order to overcome the problems and develop Da Lat City sustainably, an optimal solution is directed, that is to promote the potential of vicinities with similar climate - soil conditions On that basis, the government approved the "General Plan of Da Lat City and its vicinities until 2030 and vision to 2050" (May 2014) According to the plan, Da Lat city will become a major city, the boundary will be expanded to vicinities and cover an area of 8.5 times as much as today The urgent problem is that there is a need for comprehensive studies and assessments of the natural potential, situation and demand of land use, thereby establishing a sustainable land use planning and solution to expand the land use spaces of Da Lat City, resolving the conflicts in exploitation and land use between spaces, and meeting the development orientation of the city in the future Researching on integrated natural geography is a comprehensive and spatially specific approach, a comprehensive research of natural and socioeconomic components in the complex interplay and interaction in a specific territory Since then, the direction and solution of resource use and socioeconomic development have been set in accordance with the geographical laws of the territory This is an effective research method for the planning of rational use of resources and nature protection in the direction of sustainable development for any territory Stemming from the urgent requirements of Da Lat city, with the desire to contribute to the city's sustainable development, the thesis: "Study on geographic basis in exploiting and using land for sustainable planning of Da Lat city and its vicinities - Lam Dong province" has been selected to perform Research objectives Establishment of scientific grounds for sustainable planning and land use of Da Lat city and its vicinities on the basis of research, exploitation and use of land based on geographic approach Research implementions - Overview of related documents, as a basis for building a theoretical basis and methods, research process of land use exploitation based on geographic approach for sustainable planning and land use of Da Lat City and its vicinities; - Analyzing characteristics of arising conditions – degeneration of soil and land resources in Da Lat city and its vicinities; - Identifying causes, process of soil degradation and evaluation of aggregated soil degradation in Da Lat city and its vicinities; - Assessing and classify land in Da Lat city and its vicinities for the main land use types; - Determining the percentile and norm system, and making a geographic zoning map of the soil of Da Lat city and its vicinities; - Proposing spatial orientation and solutions for sustainable land use planning in Da Lat city and its vicinities Research area and objects - Research area: Da Lat city and its vicinities (including Lac Duong, Don Duong, Duc Trong and Lam Ha districts) - Research objects: Arising geographical factors - degradation and land resources Protected thesic points - Point 1: The diverse and complex differentiation of the soil cover reflects the specific geographic laws and the corresponding processes of land generation, development and degradation in the territory of Da Lat city and its vicinities, expressed through a system of land units and geographic zoning units with diverse characteristics and potentials - Point 2: Integrating results of research on characteristics and directions of land use and protection of each soil sub-region with results of land classification and soil degradation assessment, creating a reliable scientific basis for the proposal of spatial orientation and solutions for sustainable land use planning of Da Lat city and its vicinities New thesic points of - Clarifying the regular characteristics and spatial division of soil cover of Da Lat city and its vicinities, as evidenced by the system of soil geographic zoning units shown on the map at 1: 100,000 scale - Proposing spatial orientation and solutions for sustainable land use of Da Lat city and its vicinities, based on an integrated analysis of the results of assessment of land classification, integrated soil degradation assessment and soil geographic zoning Scientific and practical contributions - Scientific contributions: Contribute to supplementing the theoretical basis and research methods of land use exploitation based on geographic approach for sustainable planning and land use of tropical highland urban areas Enrich the research direction of applied geography in rational planning and protection of natural resources for sustainable development of the territory - Practical contributions: The research results are a scientific basis for the locality to refer to territorial organizations, planning and land use planning in the orientation of sustainable development The structure of the thesis In addition to the introduction, conclusions and recommendations, references and appendices, the thesis content consists of chapters: Chapter Theoretical basis and research methods of land use exploitation with geographic approach for sustainable planning and land use Chapter Characteristics of arising geographical conditions degeneration of soil and land resources in Da Lat city and its vicinities; Chapter Evaluation, classification of land and general land degradation in da lat city and its vicinities; Chapter Proposal of spatial orientation and sustainable land use solutions for Da Lat city and its vicinities Chapter THEORETICAL BASIS AND RESEARCH METHODS OF LAND USE EXPLOITATION WITH GEOGRAPHIC APPROACH FOR SUSTAINABLE PLANNING AND LAND USE 1.1 Some used concepts 1.1.1 Soil, land, land resources and environment 1.1.1.1 Soil From a biological perspective, V.V Docuchaev (1879) gave the definition: “Soil is a natural entity with its own developmental origin and history, an entity with complex and diverse processes taking place in it, formed under the mutual influence of basement rocks, topography, climate, organisms, humans and time” Fertility is a basic property of the soil, defined: “Fertility is the ability of the soil to provide plants with water, mineral nutrients and other necessary elements (air, temperature, etc) for plants to grow and develop” 1.1.1.2 Land According to FAO (1976), Land covers all elements of the natural environment, which affect land use potential, including climate, topography, soil, hydrology, organisms, and results of human activity in the past and present So land is a broader concept than soil 1.1.1.3 Land resources and environment Land resources: It is understood as the entire crust of the earth in which organisms and humans can live Land environment: Is a complex ecosystem, formed through physical, chemical and biological processes 1.1.2 Land evaluation and soil degradation 1.1.2.1 Land evaluation Land evaluation is defined as:“Assess the effectiveness of land when used for a specific purpose, involving the conduct of studies on soil, climate, vegetation and other aspects of land to identify and compare the requirements of specific types of land use and land conditions for the purpose of the evaluation” (FAO, 1976, 2007) 1.1.2.2 Soil degradation As defined by FAO (2002): “Soil degradation is a temporary or permanent decrease in the productive capacity of soil" From the perspective of synthetic natural geography, Nguyen Dinh Ky (1987, 1990) stated that: “In the stage of generation, development, soil degradation is governed by inherent natural processes called potential degradation Degeneration of each element of soil properties or comprehensive degradation in each time of land use exploitation is considered as current degradation” 1.1.3 Sustainable land use and land use planning, space organization 1.1.3.1 Sustainable land use Sustainable land use is a form of land use that helps maintain the soil's natural fertility and allows efficient production and regeneration of natural resources on a long-term basis FAO (1993) developed the definition of specific sustainability in agriculture: "Sustainable agricultural land use is a type of land use that can produce enough to meet the needs of current and future residents while preserving and improving land resources to ensure production." 1.1.3.2 Land use planning FAO/UNEP (1999) gave the definition: "Land use planning is a systematic evaluation of land and water potentials, land use plans and socio-economic conditions to select and apply the best land use plans." In other words, land use planning is the key to a sustainable development of a territory 1.1.3.3 Space Organization The concept of spatial organization or territorial organization is agreed to be: The arrangement and coordination of objects in multidisciplinary relationships in a specific area in order to rationally use natural, labor potentials, socio-economic geographic location and technical facilities have been and will be built to bring about high socio-economic benefits and improve the living standards of the people in that region Spatial/ territorial organizations devise integrated and regional development strategies for each region to achieve the territorial sustainable development goals 1.2 Overview of research works on land evaluation, land classification and soil degradation 1.2.1 The research works on land evaluation and classification 1.2.1.1 In the world Irrigated land classification (1951) and potential-based land classification (1961) are two evaluation systems built specifically for the condition of the United States based on the constraints of land that interfere with land use; Evaluate and classify land according to V.V Docuchaev's point of view in Russia and Eastern Europe (1960) by scoring derived factors and soil properties on the basis of an agreed benchmark scale In order to unify worldwide land evaluation standards, FAO (1976) developed "Land evaluation framework" Actually, this is a set of principles and methods, on which the land evaluation systems of any country and at any rate can be built FAO also provided specific guidance on the detailed application of the "evaluation framework" for specific subjects such as: Land evaluation for rain-fed agriculture (1983), Land evaluation for forestry (1984), Land evaluation for irrigated agriculture (1985), Land evaluation for extensive pastures (1991) At the same time, along with the development of technology and its application in the land evaluation process has contributed to quantification and correction of research results Studies on land evaluation based on FAO's guiding framework and GIS application have become popular in the world, mainly in the following directions: GIS application and available utilities of GIS; GIS integration and advanced tools (RS, GPS, etc); GIS integration and automated soil evaluation software (ALES) In addition, FAO has also provided specific guidelines on the land evaluation process in land use planning for sustainable development, such as: land evaluation for development (1986), guidelines for land use planning (1993), land evaluation framework for sustainable land management (FESLM, 1993), planning for sustainable use of land resources (1995) and two latest guidelines on integrated planning for sustainable management of land resources (1999) and land evaluation towards a revised framework (2007) These guidelines have suggested considering factors related to sustainability (natural suitability, high economic efficiency, social acceptance and no negative impact on the environment) in the land evaluation process, using the multi-criteria decision analysis (MCDA) 1.2.1.2 In Vietnam Since the late 1980s, FAO land evaluation studies have been conducted extensively in localities across the country Land evaluation becomes a mandatory rule in land use planning The works are carried out from large ecological regions to provinces, districts and specific research areas, for example: at regional level, there are studies of Vu Cao Thai (1988), Tran An Phong (1992), Nguyen Van Toan (2005), Vu Nang Dung (2015), etc; At the detailed level, there are studies of Nguyen Khang (2001), Tran An Phong (2002, 2004), Luu The Anh (2003), etc At the same time, along with the technological development of the world, current studies on land evaluation in our country are applying GIS, in addition to combining with RS, GPS and automated soil evaluation software and multi-criteria decision analysis Some typical works by: Tran An Phong (2001), Nhu Thi Xuan (2006), Le Canh Dinh (2011), Vu Nang Dung (2014), Nguyen Thanh Tuan (2015), etc 1.2.2 The research works on soil degradation assessment 1.2.2.1 In the world Researching on soil degradation is gradually opened as a research direction in soil science for effective planning and sustainable land use From 1987-1990, the project “Global Assessment of Human-induced Soil Degradation (GLASOD)” developed by UNEP and ISRIC to produce a map of global soil degradation status at 1: 10,000,000 scale In addition to global-scale studies, soil degradation has also been studied in detail for regions, countries and territories, including the following typical works: Project on Assessment of Soil Degradation in South and Southeast Asia (ASSOD) (FAO and ISRIC, 1994-1997); Project on Assessment of Soil Degradation in Central and Eastern Europe (SOVEUR) (FAO and ISRIC, 1997-2000); Project on Assessment of Soil Degradation in dry areas (LADA) in countries: Argentina, China, Cuba, Senegal, South Africa and Tunisia (FAO and GEF, 2002-2008); Assessment of Soil Degradation in Togo ( ORSTOM, 1991 - 1994); Soil degradation research in India (NBSS, 1992); Global Soil degradation Mapping (Gibbs HK, et al, 2015) 1.2.2.2 In Vietnam The studies of soil degradation in our country began in the late 1960s and gradually became a research branch of soil science, focusing on the following directions: Studies on soil degradation according to types of degradation: typical studies on soil degradation due to erosion by Nguyen Quang My (1980, 2005), Nguyen Trong Ha (1996), etc; Studies on land degradation according to types of degradation (with application of ASSOD system) of Vo Quang Minh (2003), Nguyen Xuan Thanh (2009), Center for Surveying and Assessing Land Resources - Ministry of Natural Resources and Environment (2009-2012) Studies on land degradation based on the aggregated natural geographic point of view of Nguyen Dinh Ky et al (1987, 1990, 1998, 2007, 2012, 2015); Studies on land degradation, and rehabilitation and restoration measures of Nguyen Tu Siem and Thai Phien (1998, 1999, 2002); In addition, studies applying other methods of soil degradation assessment have been implemented, such as those of Nguyen Quang Viet (2014); Nguyen Thi Thuy (2016) 1.2.3 The research works in Da Lat city and its vicinities 1.2.3.1 Studies on land evaluation and classification From 1995 to 2010, the People's Committee of Lam Dong Province conducted the program "Evaluation of agricultural land in Lam Dong", conducted by the Southern Soils and Fertilizers Research Institute - SFRI Based on FAO (1976) guidelines, assessment of agricultural land for communes at 1/10,000 scale maps, districts/cities at 1/25,000 scale to assess land quality, proposed land use and crop intensive measures From 2009 to 2012, Center for Surveying and Assessing Land Resources Vietnam General Department of Land Administration conducted Land evaluation for agricultural production land in Lam Dong province at 1/100,000 scale From 2011-2015, National Institute of Agricultural Planning and Projection conducted Land evaluation and proposing solutions for sustainable development of industrial crops and food crops in Lam Dong at 1/ 100,000 scale In addition, there are detailed land evaluation studies in districts, such as those of Le Canh Dinh and Pham Quang Khanh, (2005); Vo Thi Phuong Thuy and Le Canh Dinh (2011); ect 1.2.3.2 Studies on soil degradation In 1998, in a cooperation program between the Institute of Geography and the French National Research Institute for Sustainable Development (IRD), author Brabant P established "Soil degradation map of Lam Dong at 1/100,000 scale" on the basis of interpreting satellite images from 1992 to 1998, combined with color aerial photographs and field survey results In 2009-2012, the Center for Surveying and Assessing Land Resources Vietnam General Department of Land Administration conducted the assessment of soil degradation status in Lam Dong province at 1/100,000 scale on the basis of applying the ASSOD soil degradation assessment system In 2011-2015, Luu The Anh, Nguyen Dinh Ky et al established potential soil degradation, current land degradation and aggregated land degradation maps of Lam Dong province at 1/100,000 scale from the perspective of aggregated natural geography 1.3 Theory of research on land use exploitation according to geographic approach for sustainable land planning and land use 1.3.1 The nature of geographic approach in the study on rational use and protection of natural resources Geography is a complete scientific system, studying the natural world on the earth's surface, development conditions and production distribution characteristics and interaction between human society and geographic environment (Le Ba Thao, 1987) The objects of the study of geoscience are the geographic objects, also known as the geographic integers, in which the geographical crust is the geographic integer at planet scale It is the interdependence and interaction between the geographic components that make up the internal differentiation of the geographical crust, forming geographic integers of different scales In order to have a basis for selecting the most appropriate territory for different uses, it is necessary to make an overall assessment of natural geographic integers according to ecological adaptation, economic efficiency, environmental and social sustainability Thus, the geographic basis within the scope of the thesis can be understood simply as the results of the study towards the integrated assessment of natural geographic integers created for various purpose of use, as a basis for proposing orientations for rational use planning and protection of natural resources for sustainable development of a territory 1.3.2 Researching on land use exploitation according to geographic approach for sustainable planning and land use Soil is a function of all other geographic factors, the most obvious expression of a geographic integer Accordingly, the soil cover as a geographic structure has the structure from the simplest (soil unit) to the most complex (soil cover) In land evaluation, land units are interpreted as soil areas with relatively homogeneous (natural and socio-economic) attributes whereby the boundaries between it and the others can be distinguished Thus, according to the geographic approach, the land units are also the geographic integers (incomplete) and are a structural unit of the soil cover Accordingly, the integrated research and evaluation of land units to determine the direction of sustainable use and exploitation for specific purposes of the territory is the geographic approach in the study of land use for sustainable planning and land use In other words, it is the study of the arrangement of land use types on land units in a sustainable manner, both in accordance with the arising geographical laws, the development of the soil cover, and promoting the maximum potential of natural land, bringing high economic efficiency and minimizing the negative impacts on land environment resources Thus, the integration of land classification and soil degradation assessment results with soil geographic zoning will more effectively show the results of land aggregate assessment in the close relationship between soil geographic sub-regions The purpose of this process is to give a direction to the land use space and develop sustainable territories, as a scientific basis in planning and land use of the territory in the direction of sustainable development 1.3.2.1 Land Unit Map Land Unit Map is the basic maps in the evaluation that completely and objectively reflects the land properties in the relationship and the reciprocal impact with arising geographic factors - soil degradation The Land Unit Mapping method is the overlap of many types of factor maps showing land properties such as: land map, topographic slope, isometric map of rain, temperature, watering ability, etc The results of the construction of the land units are relatively uniform in all criteria, shown on the map as lands with enough characteristics to make a difference with the other land units plateau: There is a tropical monsoon climate, cool and cold, with an average temperature of 18.20C, the average rainfall of 1865mm/ year and the dry season is months long; (2) Climate zone of Lam Ha - Duc Trong Don Duong: There is a warm-to-hot tropical monsoon climate, no cold season, the average annual temperature of 21.30C, the coldest month’s temperature is 19.60C, average annual rainfall is 1577.4 mm/year, dry season for 3-4 months 2.1.4.2 Hydrological characteristics a Surface water: Located in high mountainous terrain with strong rainfall, the network of rivers and streams in ther research area is quite rich The two main rivers are Da Dang and Da Nhim Rivers b Groundwater: Groundwater reserves of the research area are distributed very unequally between regions and can be divided into the following water storage units: (1) The gap aquifers; (2)The cracked aquifers 2.1.5 Characteristics of vegetation 2.1.5.1 Natural forest vegetation: including broad-leaved evergreen closed forest; mixed broad-leaved and coniferous forests; thin coniferous forest; bamboo forest; bush and grassland 2.1.5.2 Artificial vegetation: plantation forest community; industrial forest community and other perennials; annual tree community 2.1.6 Human activities in land exploitation and use The increase in mechanical population in recent years has put pressure on environmental resources - the need to use land for socio-economic development is great Most of the area has been put into use, of which the group of agricultural land is 384,808.8 ha, accounting for 92.7% of natural land, including agricultural production land which is 157,058.8 ha, accounting for 37.8% of natural land and forestry land is 226,451.2 ha, accounting for 54.6% of the natural area; Non-agricultural land is 24,843.0 ha, accounting for 6.0% of natural area There is also unused land which is 5,450.1 ha, accounting for 1.3% of natural area In the agricultural land group of the region, there are main types of land use for agro-forestry production, including: Types of annual land use (rice, crops (vegetables, flowers)); Types of perennial tree land use (coffee, tea, mulberry, fruit trees); Types of land use for forestry production (three-leaf pine) 2.2 Characteristics of land resources in Da Lat city and its vicinities 2.2.1 Processes of land generation: The process of washing and accumulating clay, the process of destroying clay minerals and accumulating aluminum iron, the process of accumulating humus and forming humus soil in mountains, the process of gleying 2.2.2 Classification system and characteristics of major soil groups Land resources in the studied area are divided into 16 land units under soil groups In particular, the zonal soil group has absolute dominance with 86.2% of the natural area, including the red-yellow soil group 13 (accounting for 85.0% of the natural area), the groups of black soil, gray soil, soil exposing gravel and rock with negligible area; The azonal soil group in high rims of mountains with an area accounting for 6.3% of the natural area, including the group of red-yellow humus soil in mountains (6.1% of the natural area) and the group of humus soils in high mountains with very small area; The inland zonal soil group on the river alluvium accounts for 6.4% of the natural area, including the valley soil on sloping products (accounting for 3.7% of the natural area) and the alluvial soil group (accounting for 2.7% of the natural area) 2.2.3 Actual soil fertility The map of actual soil fertility reflects the soil fertility at the time of the study On the basis of analyzing and combining component maps according to the norms with clear differentiation among soil types including: pHKCl, OM, Nts, P2O5dt, K2Odt, CEC by the method of scoring and calculating the average, it has divided the actual fertility of the studied area into levels as follows: The land area with high fertility occupies a large proportion in the studied area, reaching 61.8% of the natural area; The land area with average fertility reaches 31.8% of the natural area; The land area with low fertility reaches 5.2% of the natural area Chapter EVALUATION, CLASSIFICATION OF LAND AND GENERAL SOIL DEGRADATIONIN DA LAT CITY AND ITS VICINITIES 3.1 Evaluation and classification of land for agricultural and forestry production in Da Lat city and its vicinities 3.1.1 Selection for promising types of land use Based on the results on surveying the current state of land use and evaluating economic efficiency of major types using agricultural - forestry production land in the studied area The types that use dominant land in area and socio-economic efficiency have been selected for the evaluatin, including: wet rice, cash crops (vegetables and flowers), Robusta coffee, Arabica coffee, tea, mulberry trees, fruit trees, three-leave pines 3.1.2 Establishing Land unit mapping 3.1.2.1 Selecting and decentralizing norms Based on the study of ecological requirements of evaluated land use types and actual land properties (including: soil, topography, climate, hydrology, irrigation) of the studied area, 12 norms have been selected to build land unit mapping, scale of 1/50,000: soil type, thickness of soil layers, mechanical composition, actual soil fertility, elevation, slope, average annual rainfall, average annual temperature, average rainfall of two months after harvest (January, February), distribution of drought areas, irrigation conditions 3.1.2.2 Land unit mapping Land unit mapping of Da Lat city and its vicinities is built by overlaying thematic maps of 12 selected norms Each land mapping unit 14 contains all the information presented in thematic maps and is distinguished from other units by the difference of at least one element The aggregate results have identified 1,129 land mapping units (LMU), which are decentralized according to the area scale in Table 3.2 Table 3.2 Summary of land mapping units according to the area scale No Area scale (ha) 1.000 Total land area Rivers, streams, lakes Total natural area Area (ha) 182.7 1,352.6 181,487.8 100,111.3 126,968.7 410,103.1 4,998.8 415,101.9 LMU quantity 176 39 693 146 75 1,129 Ratio (%) 0.1 0.3 44.3 24.4 31.0 98.8 1.2 100.0 3.1.3 Determining ecological requirements of land use types Based on natural conditions in the studied area and referring to values of ecological requirements of tropical and subtropical crops of Sys Ir C., (1993), and inheriting the relevant results of studies, the ecological requirements of land use types have been determined in levels of suitability: S1 - very suitable, S2 - suitable , S3 - less suitable and N - not suitable 3.1.4 Results on evaluating and classifying land for agriculture and forestry production The evaluation and classification are done by comparing the characteristics of land units with ecological requirements of the selected land use types, according to evaluation methods (limited conditions, dominant factors) and levels of land suitability (S1, S2, S3, N) of FAO (section 1.3.2.1), based on the integration of Automated Land Evaluation Software ALES and geographic information system GIS The result is that the land suitablity classification maps for different types of agricultural and forestry production land use in the studied area are built at 1/50,000 scale (Table 3.4) Table 3.4 Area of land suitability level by types of land use LUTs Rice Cash crops (vegetables, flowers) Robusta coffee Arabica coffee Area / Ratio Ha % Natural land area Ha % Natural land area Ha % Natural land area Ha % Natural land area Levels of suitablity Very Less Suitable suitable suitable (S2) (S1) (S3) 5,336.9 16,256.0 7,467.3 Not suitable (N) Total natural land area 381,042.9 410,103.1 1.3 4.0 1.8 92.9 100.0 8,588.3 71,999.1 14,953.7 314,562.0 410,103.1 2.1 17.2 3.6 77.1 100.0 2,417.8 29,308.9 56,677.1 321,699.3 410,103.1 0.6 7.1 13.8 78.4 100.0 - 52,760.8 111,144.3 246,197.9 410,103.1 - 12.9 27.1 60.0 100.0 15 Tea Mulberry trees Fruit trees Threeleave pines Ha % Natural land area Ha % Natural land area Ha % Natural land area Ha % Natural land area - 44,677.7 130,960.3 234,465.1 - 10.9 31.9 57.2 410,103.1 100.0 14,798.4 30,910.2 25,753.0 338,640.6 410,103.1 3.6 7.5 6.3 82.6 100.0 12,360.1 50,169.6 104,992.8 242,580.6 410,103.1 3.0 12.2 25.6 59.2 100.0 7,330.5 121,898.1 227,290.9 53,583.5 410,103.1 1.8 29.7 55.4 13.1 100.0 3.2 Evaluation on integrated soil degradation in Da Lat city and its vicinities 3.2.1 Causes and specific soil degradation processes 3.2.1.1 Causes of soil degradation include: (1) Natural causes: The topography is steep, sharply divided; Concentrated season rain and profound division of rainy season and dry season; Drought; (2) Activities of exploiting and using land by human: Deforestation for agricultural land; Unsustainable cultivation on sloping land; Using chemical fertilizers and pesticides; Urbanization and infrastructure development; Activities of mining and mineral processing 3.1.1.2 Processes of soil degradation include: Erosion, washout; Feralite laterite forming clumps, laterite; Chemical degradation; Gley; landslide; Soil pollution 3.2.2 Evaluation on soil degradation 3.2.2.1 Evaluation on potential soil degradation On such basis, analyzing and evaluating the factors and processes of soil generation - degradation of the studied area, allowing to select and decentralize norms for evaluating potential soil degradation, including norms under types as follows: Soil (basement rock/specimen, mantle rock and thickness of soil layers); Topography (topography morphology and topography slope); Climate (degree of drought); Potential erosion level The combination of component maps corresponding to the evaluation norms allows the creation of potential soil degradation maps at the scale of 1/50,000 under grades: Light degradation potential (TN1) occupies the smallest area of 30,579.3 ha, equivalent to 7.4% of total natural area; Average degradation potential (TN2) occupies an area of 135,007.3 ha, equivalent to 32.5% of total natural area; Strong degradation potential (TN3) occupies a very large area with 244,516.5 ha, equivalent to 58.9% of total natural area 3.2.2.2 Evaluation on current soil degradation Based on the characteristics of the studied area, the norms are selected and decentralized to evaluate the current soil degradation, including: the humus content (OM%), the current state of indicator vegetation and the current erosion level The combination of component maps corresponding to the evaluation 16 norms allows the creation of the current soil degradation map in the studied area at the scale of 1/50,000 under grades: none or weak degradation (HT1) dominates with 250,168.4 ha, equivalent to 60.3% of the natural area; Average degradation (HT2) with114,133.0 ha, accounting for 27.5% of the natural area; Strong degradation (HT3) with 45,801.6 ha, accounting for 11.0% of the natural area 3.2.2.3 Evaluation on general soil degradation Based on the matrix of combination between potential soil degradation and current soil degradation, it is allowed to evaluate the level of general soil degradationin the studied area on a map with scale of 1/50,000 under grades: Slight degradation (TH1) with an area of 92,684.8 ha, accounting for 22.3% of the natural area; Average degradation (TH2) with the largest area of 294,168.3 ha, accounting for 70.9% of the natural area; Strong degradation (TH3) with the smallest area of 23,249.9 ha, accounting for 5.6% of the natural area Chapter PROPOSAL OF SPATIAL ORIENTATION AND SUSTAINABLE LAND USE SOLUTIONS FOR DA LAT CITY AND ITS VICINITIES 4.1 Soil geographic zoning of Da Lat city and its vincinities 4.1.1 The specificity in the differentiation of soil cover The differentiation of soil cover by geographical latitude to form soil geographic zoning units is not clearly shown by the influence of azonal factors, of which the topography is the dominant factor that makes the differentiation However, the general nature of the soil geographic zoning unit system is still determined by its sub-equatorial tropical monsoon climate factor 4.1.2 Percentile system and norms of soil geographic zoning The percentile system used for soil geographic zoning maps of Da Lat city and its vinicities at a scale of 1/100,000 includes: soil geographic regional level and sub-regional level In particular, each level has specific zoning norms as follows (Table 4.1) Table 4.1 The soil geographic zoning system No Percentile level Region Sub-region Zoning norms The homogeneity of soil complexes differentiated by topography elevation, bioclimatology and characteristics of basement rock/speciment on the territory formed soil geographic regions Of which, the dominant factordifferentiation is topography The homogeneity of soil complexes differentiated according to topography and land use characteristics of each region separates into soil geographic sub-regions 4.1.3 Results of geographic zoning in Da Lat city and its vicinities On the basis of the percentile system and norms of levels used in soil geographic zoning in Da Lat city and its vicinities at the scale of 1/100,000 The soil cover of the studied territory is divided into soil geographic regions with 19 sub-regions with different characteristics and directions of land use and protection - Region with humus - yellow red feralite soil in medium mountains of Chu Yang Sin (I), is differentiated into sub-regions, of which the red-yellow 17 feralite sub-region on the acidic magma and sediments of North Lac Duong (Sub-region 1) with the largest area, accounting for 9.1% of the natural area - Region of feralite - yellow red humus land in the plains and highlands of Dalat (II), is differentiated into sub-regions, of which sub-region with yellow red feralite soil on neutral magma to South Dalat acid (Sub-region 8) with the largest area, accounting for 8.5% of the natural area - Region with red yellow feralite soil in low mountains of West Chu Yang Sin (III), is differentiated into sub-regions, of which sub-region with yellow red feralite soil on neutral magma to acid and sediments of West Lam Ha (Sub-region 9) with the largest area, accounting for 3.6% of the natural area - Region with red brown, yellow brown feralite soil in Lam Ha - Duc Trong basalt plateau (IV), is differentiated into sub-regions, of which the subregion with yellow-brown feralite soil and sloping soil on basalt of South Lam Ha (Sub-region 13) with the largest area, accounting for 9.7% of the natural area - Region with red yellow feralite soil in low mountains of Don Duong - Duc Trong (V), is differentiated into sub-regions, of which, the sub-region with yellow red feralite soil on shale of South Duc Trong (Sub-region 18) with the largest area, accounting for 8.3% of the natural area 4.1.4 Summary of evaluation results, land classification and soil degradation according to soil geographic sub-regions 4.1.4.1 Results of land suitability classification S1, S2 according to soil geographic ub-regions Based on the results of evaluating land classification for agriculture and forestry development in Da Lat city and its vicinities, the thesis has synthesized the land area with the rating class that is very suitable (S1) and suitable (S2) for selected land use types: annual crops (rice, cash crops), perennial crops (Arabica coffee, Robusta coffee, tea, mulberry trees, fruit trees), artificial forests ( three-leave pines) classified by soil geographic sub-regions The results have shown the land potential for agro-forestry development of soil geographic sub-regions 4.1.4.2 Results on evaluating general soil degradation according to soil geographic sub-regions Based on the results on evaluating general soil degradation in Da Lat city and its vicinities, the thesis has synthesized the area of soil degradation levels by soil geographic sub-regions The results have shows the warning level of soil degradation in exploitation and use by soil geographic subregions 4.2 Analysis for development planning and plans related to the territory of Dalat city and its vicinities Including: Agriculture and forestry development planning and plans for the 2016-2025 period and orientation to 2030; Spatial development planning for Da Lat city until 2030 and vision to 2050 18 SOIL GEOGRAPHIC ZONING MAP OF DA LAT CITY AND ITS VICINITIES Prepared by: Postgraduate Nguyen Thi Thuy 4.3 Spatial orientation and sustainable land use solutions for Da Lat city and its vicinities 4.3.1 Orientation of sustainable land use spaces for Da Lat city and its vicinities From the results on evaluating, classifying land and general soil degradation, combined with the synthesis and analysis of such results with the current state of land use, characteristics and directions of land use - protection of soil geographic sub-regions, the development planning and plans of agriculture and forestry sectors, spatial development planning of Da Lat city and its vicinities, the thesis proposes spaces of sustainable land use by land unit of Da Lat city and its vicinities The results are shown in Table 4.6 Table 4.6 The result for orientation of sustainable land use spaces by land units No 1.1 1.1.1 1.1.2 1.1.3 1.2 1.2.1 1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 2.1 2.2 Land use types Land for agriculture production Annual crop land Rice land Land for cash crops Land for other annual crops Land for perennial crops Land for Arabica coffee Land for Robusta coffee Land for tea Land for mulberry trees Land for fruit trees Land for other perennial crops Forestryland Forest land for three-leave pines Land piece for regenerating natural forests 2.3 Forest land with forests and culturing piece for protecting natural forests Urban land 3.1 Residential land 3.2 Other non-agricultural land Unused land Other land Total land area Rivers, streams Total natural area Current state Diện tích Tỷ lệ (ha) (%) 157,058.7 37.8 44,374.7 10.7 9,144.7 2.2 26,958.1 6.5 8,271.9 2.0 112,684.0 27.1 15,928.0 3.8 88,792.6 21.4 932.4 0.2 1,619.0 0.4 4,650.0 1.1 762.0 0.2 226,451.2 54.6 17,563.4 4.2 Proposal Diện tích (ha) 118,573.8 42,219.6 7,939.6 26,278.6 8,001.4 76,354.2 16,931.0 50,086.0 907.1 2,560.1 5,135.4 734.6 270,386.2 52,648.9 Tỷ lệ (%) 28.6 10.2 1.9 6.3 1.9 18.4 4.1 12.1 0.2 0.6 1.2 0.2 65.1 12.7 Increase/ decrease (ha) -38,484.9 -2,155.1 -1,205.1 -679.5 -270.5 -36,329.8 1,003.0 -38,706.6 -25.3 941.1 485.4 -27.4 43,935.0 35,085.5 0.0 8,849.5 2.1 8,849.5 208,887.8 50.3 208,887.8 50.3 19,844.4 5,521.1 14,323.3 5,450.1 1,298.8 410.103,1 4.998,8 415.101,9 4.8 1.3 3.5 1.3 0.3 98.8 1.2 100.0 19,844.4 5,521.1 14,323.3 1,298.8 410.103.1 4.998.8 415.101.9 4.8 1.3 3.5 0.0 0.3 98.8 1.2 100.0 0 -5,450.1 0 0 4.3.2 Spatial orientation for developing soil geographic sub-regions of Da Lat city and its vicinities Based on the summary of the orientation of sustainable land use spaces by soil geographic sub-regions, the analysis of characteristics and directions of land use and protection of soil geographic sub-regions, and at the same time referring to the spatial development planning of Dalat city until 2030 and vision to 2050, the thesis proceeds orienting the structure of land use spaces and development spaces for soil geographic sub-regions as a basis for sustainable territorial organization of Da Lat city and its vicinities, the results are shown in Tables 4.8 and 4.9 19 Table 4.8 Orientation for the structure of sustainable land use spaces by soil geographic sub-regions Subregions Subregion Subregion Subregion Subregion Subregion Subregion Subregion Subregion Subregion Subregion 10 Subregion 11 Subregion 12 Subregion 13 Subregion 14 Subregion 15 Subregion 16 Subregion 17 Subregion 18 Subregion 19 Annual crops Perennials 0.2 0.1 Agricultural development: 0.3 0.2 0.2 Agricultural development: 0.4 0.3 0.6 Agricultural development: 1.0 4.7 4.4 Agricultural development: 9.0 10.4 5.6 Agricultural development: 16.0 19.7 5.3 Agricultural development: 25.0 1.4 20.7 Agricultural development: 22.1 3.9 1.9 Agricultural development: 5.8 5.5 Agricultural development: 5.5 7.8 51.5 Agricultural development: 59.4 10.9 52.2 Agricultural development: 63.1 21.9 32.7 Agricultural development: 54.6 12.8 70.1 Agricultural development: 82.9 16.8 53.8 Agricultural development: 70.5 42.8 18.1 Agricultural development: 60.9 3.1 1.3 Agricultural development: 4.4 Forest land with forests and Artificial culturing forests piece for protecting natural forests 1.2 3.0 95.6 Forestry development: 99.8 0.9 2.0 96.7 Forestry development: 99.5 3.4 0.4 89.8 Forestry development: 93.5 8.5 1.1 79.7 Forestry development: 89.2 25.3 3.9 47.4 Forestry development: 76.6 Land piece for regenerating natural forests Urban land 0.1 0.1 0.8 3.5 22.9 0.8 31.7 Forestry development: 55.4 18.5 23.6 0.1 50.6 Forestry development: 74.3 3.5 2.2 62.8 Forestry development: 90.8 23.5 2.8 67.4 Forestry development: 93.7 26.6 4.7 6.0 Forestry development: 37.2 2.2 23.4 1.3 6.8 Forestry development: 31.5 5.2 17.9 0.7 2.8 Forestry development: 21.4 21.7 1.8 1.4 4.1 Forestry development: 7.3 7.7 7.4 0.3 10.1 Forestry development: 17.8 5.3 17.4 1.6 9.2 Forestry development: 28.1 10.0 16.7 2.0 76.4 Forestry development: 95.1 0.4 1.7 0.1 Agricultural development: 1.8 7.2 42.0 48.9 Forestry development: 98.1 0.1 11.3 1.6 Agricultural development: 12.9 26.9 28.8 Agricultural development: 55.7 14.1 0.7 67.7 Forestry development: 82.4 2.5 9.1 0.2 23.5 Forestry development: 32.8 6.4 25.8 20 0.1 3.3 Table 4.9 Statistics of development priority spaces of soil geographic sub-regions Orientation of development spaces Forestry preserving biodiversity, protecting and supplying water Protection and production forestry Priority for preservation and restoration for developing specialuse and protective natural forests Priority for protection and development of riverhead protective forests and special-use forests Priority for protection and development of protective natural forests and production forests in reservoir basins Priority for protection and development of protective natural forests in reservoir basins and planting production forests Priority for protection of protective forests and development of production forests Priority for protection of protective forests and development of production forests Priority for development of production forests and restoration of regenerating natural forests Production forestry and agro-forestry models Priority for development of natural production forests and agroforestry models Priority for protection and development of protective natural forests, production forests and agroforestry models Priority for protection and development of protective natural forests in reservoir basins, agroforestry models Specialized agriculture, agroforestry models and populations Priority for development of agriculture specializing in perennial crops and agroforestry models Priority for development of agriculture specializing in perennial crops, agro-forestry models and populations Priority for development of agriculture specializing in perennial crops and populations Priority for development of agriculture specializing in perennial crops, agro-forestry models and populations Priority for development of agriculture specializing annual crops, agro-forestry models and populations Priority for development of specialized agriculture, agroforestry model and populations Satellite towns Center towns Priority for protection of protective natural forests in reservoir basins and development of satellite towns in combination with forestry-agriculture models Priority for development of satellite towns, specialized agriculture and agroforestry models Priority for preservation and development of natural forests and traditional urban landscapes combied with ecological agriculture Subregions Subregion Subregion Subregion Subregion Subregion Subregion 16 Subregion 17 Subregion Subregion Subregion 18 Subregion 10 Subregion 11 Subregion 13 Subregion 14 Subregion 15 Subregion 19 Subregion Subregion 12 Subregion 4.3.3 Solutions for sustainable land use in Da Lat city and its vicinities 4.3.1.1 Solutions to prevent, limit and improve generally degraded soil: Consist of cultivation solutions, construction solutions, biological solutions 4.3.3.2 Solutions for sustainable land use according to type of land use Based on the level of general soil degradationaccording to major land use types and sustainable land use orientations according to land units in the studied area, solutions for sustainable land use according to land use types on the general soil degradationunits are proposed 21 SPATIAL ORIENTATION MAP FOR SUSTAINABLE LAND USE IN DA LAT CITY AND ITS VICINITIES Prepared by: Postgraduate Nguyen Thi Thuy 4.3.3.3 Solutions for sustainable land use according to soil geographic sub-regions Based on the level of general soil degradationaccording to soil geographic sub-regions and the orientation of sustainable land use according to soil geographic sub-regions in the studied area, solutions for sustainable land use according to each soil geographic sub-region are proposed CONCLUSION AND RECOMMENDATION Conclusion: Da Lat City and its vicinities are urban areas with special and important geopolitical - economic - cultural and social positions of the Central Highlands and the whole country There is a dynamic process of socio-economic development in all fields of agriculture - forestry - industry - tourism, services - urbanization in such regions Therefore, the contradictions of benefits and environmental conflicts appear in exploitation and use of land, disrupting ecological balance and natural landscape structure The thesis meets the urgent target which is to provide a scientific basis for the planning and sustainable use of land in Da Lat city and its vincinities with orientations to 2030 and a vision to 2050, contributing to the government's orientation that brings this city to become a city under the central government Dalat city and its vicinities belong to the specific ecological geography of sub-equatorial tropical monsoon in mountains and layered plateaus of the Central Highlands The medium high mountains (10001500m) are composed of acid magma rocks and mixed sediments, the steep and wavy plateaus consists of layers, the upper layer (> 1500m) is the plain and highlands of Da Lat, it is composed mainly of granite, daxite rocks and sediments, and the lower layer (800-1000m) is the Lam Ha - Duc Trong plateau composed mainly of basalt rocks The combination of the zonal, azonal rules and factors with the forming conditions have created a diversified soil cover with groups and 16 different soil types, of which the zonal soil group (F) absolutely predominates with 86.2% of the natural area, the remaining azonal soil group in the high mountains (H, A) accounts for 6.3% of the natural area and the inland zonal soil group on the fluvial alluvium (P, D) accounts for 6.4% of the natural area Geographical basis in exploiting and using land for sustainable planning of Da Lat city and its vicinities is the result of aggregate study and assessment on land based on the integration of land classification assessment results (for types of dominant agro-forestry land use), integrated soil degradation assessment and soil geographic zoning In particular, the land unit is selected as the basic unit to orient the space for sustainable land use, while the unit of soil geographic sub-region is the basic unit to orient the space for sustainable territory development - Suitable land evaluation and classification for sustainable agricultural and forestry production not only solve the targets of ensuring food security, economic development (supplying raw materials for processing and exporting industries) but also protect land, water and forest resources in the 22 territory, protect the natural environment in the mountainous highland urban areas The suitable scale of land evaluation in Da Lat city and its vicinities include 12 norms: soil type, thickness of soil layers, mechanical composition, actual soil fertility, elevation, slope, average annual rainfall, average annual temperature, average rainfall of two months after harvest (January and February), distribution of drought areas, irrigation conditions The land unit mapping of Da Lat city and its vicinities at the scale of 1: 50,000 is created by combining norm maps in GIS to identify land units, including 1,129 land units Results on evaluation and classification of land suitability by the integrated method of ALES - GIS has determined the area and allocation for suitable levels of promising agricultural and forestry land use types, of which: Land area suitable (S1, S2) for rice cultivation is 5.3%, for cash crops (vegetables, flowers) is 19.3%, for Arabica coffee is 12.9%, for Robusta coffee is 7.7%, for tea is 10.9%, for mulberry trees is 11.1%, for fruit trees is 15.2% and for threeleave pines is 31.5% of the natural area - There are major soil degradation processes in Dalat city and its vicinities: Erosion - washout; Feralite - laterite forming laterite; Chemical degradation; Gleying; Landslides; Soil pollution Evaluation on general soil degradation based on the correlation matrix between potential soil degradation (T) and current soil degradation (H) in GIS environment will allow to forecast the soil degradation levels of soil structure unit when being used for specific purposes, which is an important basis forsustainable land planning and use of the territory The size of general soil degradationlevels in Da Lat city and its vicinities at the scale of 1: 50,000 is as follows: Weak general degradation (TH1) accounts for 22.3%, average general degradation (TH2) accounts for 70.9%, strong general degradation (TH3) accounts for 5.6% of the natural area - The differentiation of soil cover in Dalat city and its vicinities according to geographical latitude (subequatorial monsoon tropical climate factor) to form soil geographic zoning units is not clearly shown by the influence of azonal rules (basement rock and topographic factors), of which the topography is the dominant factor that makes the differentiation Applying the principles (aggregation and dominant factors, relative homogeneity, common territory) and zoning methods (dominant factors, method of analyzing component maps and expert method) to determine soil geographic regions and sub-regions The results have divided the soil cover of the studied area into soil geographic regions with 19 soil geographic sub-regions which have separate characteristics and directions of land use and protection, which are the basis for proposing land use spatial orientation and sustainable development under territory - Summarizing the results of land classification and evaluation and evaluation of general soil degradation, combined with analyzing such results and current state of land use, characteristics and directions of land use and protection of soil geographic sub-regions, planning and plans for development of agriculture and forestry sector, spatial development planning of Da Lat city and its vicinities are used as the basis for proposing 23 the orientation of sustainable land use spaces according to land units and orientation of territorial development spaces according to soil geographic sub-regions as follows: For land units: (1)Space for using agricultural production land: Accounting 28.6% of the natural area, including rice land accounting for 1.9%, land for cash crops (vegetables, flowers) accounting for 6.3%, land for other annual crops accounting for 1.9%, land for Robusta coffee accounting for 12.1%, land for Arabica coffee accounting for 4.1%, tea land accounting for 0.2%, land for mulberry trees accounting for 0.6%, land for fruit trees accounting for 1.2%, land for other perennial crops accounting for 0.2% of the natural area; (2) Space for using forestry land: accounting for 65.1% of the natural area, of which forest land for three-leaf pines accounting for 12.7%, forest land with forests and restoration for forest protection accounting for 50.3%, and land for restoring and regenerating natural forests accounting for 2.1% of the natural area; (3) Space for using urban land: Accounting for 4.8% of the natural area and when it is necessary to expand non-agricultural land for the target on developing a future city, it can be taken from the land fund that the topic has oriented for agricultural development For soil geographic sub-regions: (1) Priority is given to forestry development and biodiversity conservation, protect and provide water sources: including sub-region 1, sub-region 2, sub-region 3; (2) Priority is given to protection and production forestry: including sub-region 8, subregion 9, sub-region 16, sub-region17; (3) Priority is given to production forestry and agro-forestry models: including Sub-region 4, Sub-region 7, Sub-region 18; (4) Priority is given to specialized agriculture, agroforestry models and populations: Sub-region 10, Sub-region 11, Sub-region 13, Sub-region 14, Sub-region 15, Sub-region 19; (5) Priority is given to satellite urban development: including Sub-region and Sub-region 12; (6) Priority is given to central urban development: Sub-region The results of analyzing levels of dominant general soil degradation based on the major land use types and soil geographic sub-regions have provided the grounds for selecting solutions to restrict, improve with suitable land use models, including: (1) cultivation solutions: Managing fertilizers associated with intensive cultivation, working soil minimum, killing weeds with biological methods to limit the use of chemicals; (2) Construction solutions: Bilding terraces combining with water retention and drainage ditches, planting trees along contour lines in combination with building dykes and ditches against erosion; (3) Biological solutions: Agroforestry models, catch-crop and crop rotation, planting of greenery to prevent erosion, planting of trees for covering soil, models of restoring forest which have been degraded Recommendations: Continuing to develop the study direction of land exploitation and use based on geographic approach for land use planning and sustainable development of tropical highland urban areas It is necessary to supplement the detailed planning to expand Dalat city to 2030 and 2050 on the basis of further study on types of urban land use 24 LIST OF PUBLISHED RESEARCHS Nguyen Thi Thuy, Luu The Anh (2017) Assessment of Basalt Soil Quality under Different Land Use Types in Bao Loc - Di Linh Area, Lam Dong Province VNU Journal of Science: Earth and Environmental Sciences, 33 (3), 67-79 Nguyen Thi Thuy, Luu The Anh (2016) Intergration of GIS and multi-criteria analysis (MCA) for potential land degradation mapping of Lam Dong province Journal of Geodesy and Cartography, 29, 33-42 Vietnam Institute of Geodesy And Cartography Luu The Anh, Nguyen Dinh Ky, Nguyen Thi Thuy and others (2016) Monograph Book of Tay Nguyen Land Resources - Current status and Challenges Publisher of Science and technology Hanoi Luu The Anh, Nguyen Thi Thuy and others (2015) Assessment of organic matter content in basalt soils under cultivation of major crops in Dak Lak province Vietnam Journal of Earth Sciences, 37 (2), 110-117 Luu The Anh, Nguyen Dinh Ky, Nguyen Thi Thuy (2013) The main land degradation types and possibility of appearing desertification in Tay Nguyen Vietnam Science and Technology, 7, 49-53 Nguyen Thi Thuy, Luu The Anh, Nguyen Duc Thanh (2014) Study on main physical and chemical properties of soil under coffee cultivation in the central highlands Proceedings of the 8th National Geographic Conference, 733-740 Luu The Anh, Nguyen Thi Thuy, Nguyen Duc Thanh, Hoang Quoc Nam (2014) Assessment of the natural fertility of the basalt soil in Daklak province using the fertility capacilty classification (FCC) Proceedings of the 8th National Geographic Conference, 478-788 Luu The Anh, Nguyen Dinh Ky, Nguyen Thi Thuy and others (2013) Guideline handbook for land description Publisher of Science and technology Hanoi 25 ... detailed land evaluation studies in districts, such as those of Le Canh Dinh and Pham Quang Khanh, (2005); Vo Thi Phuong Thuy and Le Canh Dinh (2011); ect 1.2.3.2 Studies on soil degradation In 1998,... (1980, 2005), Nguyen Trong Ha (1996), etc; Studies on land degradation according to types of degradation (with application of ASSOD system) of Vo Quang Minh (2003), Nguyen Xuan Thanh (2009), Center... analysis Some typical works by: Tran An Phong (2001), Nhu Thi Xuan (2006), Le Canh Dinh (2011), Vu Nang Dung (2014), Nguyen Thanh Tuan (2015), etc 1.2.2 The research works on soil degradation assessment