Thesis summary for Geography doctor: Study on geographic basis in exploiting and using land for sustainable planning of Da Lat city and its vicinities - Lam Dong province

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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.

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Nội dung Text: Thesis summary for Geography doctor: Study on geographic basis in exploiting and using land for sustainable planning of Da Lat city and its vicinities - Lam Dong province

MINISTRY OF EDUCATION VIETNAM ACADEMY OF AND TRAINING 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: 9 44 02 20 THESIS SUMMARY FOR GEOGRAPHY DOCTOR Hà Nội - 2019
The thesis was completed in: Graduate University of Science and Technology- Vietnam 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 1. 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 socio- economic components in the complex interplay and interaction in a specific territory. Since then, the direction and solution of resource use and socio- economic 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. 1
2. 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. 3. 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. 4. 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. 5. 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. 6. 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. 2
7. 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. 8. The structure of the thesis In addition to the introduction, conclusions and recommendations, references and appendices, the thesis content consists of 4 chapters: Chapter 1. Theoretical basis and research methods of land use exploitation with geographic approach for sustainable planning and land use Chapter 2. Characteristics of arising geographical conditions - degeneration of soil and land resources in Da Lat city and its vicinities; Chapter 3. Evaluation, classification of land and general land degradation in da lat city and its vicinities; Chapter 4 Proposal of spatial orientation and sustainable land use solutions for Da Lat city and its vicinities. Chapter 1. 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. 3
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 4
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. 5
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 6 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). 6
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. 7
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. 8
1.3.2.2. Evaluation and classification of natural land Land evaluation and classification are actually the process of comparing the inherent properties of the land units with the land properties that the land use type requires, in order to classify the natural suitability of a land unit with that land use type. Level of suitability is a measure of how well a land unit ensures the needs of the land use type evaluated. The land evaluation and classification are determined according to the following principles, standards and popularity (FAO, 1976, 1983, 1984, 1985): Evaluation principles: (1) Limitations, (2) Dominant factors; Level of suitability: (1) Very suitable (S1), (2) Medium suitable (S2), (3) Less suitable (S3), (4) Not suitable (N). 1.3.2.3. General land degradation evaluation The nature of soil degradation is the process of changing the properties of the soil leading to a reduction or loss of production capacity. The causes of degeneration are very diverse, complicated and associated with the conditions of soil generation, some places are mainly caused by nature and some are caused by humans, which are divided into different types according to the degenerating agent. (Nguyen Dinh Ky, 1987, 1990): (1) Potential soil degradation is the ability of natural fertility degradation of the soil due to natural processes. It is assessed by the soil degradation potential of soil-generated geographic conditions (including: basement rock/ age of basement rock, mantle rock, topographical and climate conditions, local hydrology) assuming no vegetation cover and human impact; (2) Current soil degradation is the current soil fertility degradation compared to the natural fertility due to the exploitation and use of humans. It is assessed by the degradation status of soil physicochemical and biological properties leading to a decrease in soil productivity; (3) General soil degradation is the result of forecasting the extent of soil degradation when used for specific purposes. It is assessed by the current fluctuation of soil degradation level based on potential soil degradation by space. 1.3.2.4. Soil geographic zoning - Percentile system inherited in the thesis: The study of natural geographic zoning in general does not have a common percentile system, each country, even each author, based on his/her experience to come up with a percentile system, to contribute a part to progress towards that common percentile system. According to Vu Tu Lap (2011), each generated land unit bears the mark of the basic natural geographic laws of zonal law and non-zonal law. The distribution of each land unit and their spatial combinations, the structure of the soil cover on the territory are necessarily subject to those laws. Therefore, when determining the natural geographic zoning units for any natural territory, it is required to analyze in detail and specifically the evolution of these laws. In Vietnam, the percentile system applies to the scale of the Vietnamese territory (1/1,000,000 scale) built by the Vietnam Soil Science Association, including 4 levels: Region - Sub – Region - Area - Zone (Ton That Chieu, 1996). Subsequent soil geographic zoning studies were primarily developed based on the inheritance of the above percentile system and zoning sign for different territories. The number of zoning units 9
may be more or less depending on the size and complexity of the studied territory. With small studied territories it is possible to divide the territory into sub-regional units. - Principles of soil geographic zoning: Include arising, aggregating and dominant factors, relative homogeneity, sharing the same territory. 1.3.3. Scientific grounds for assessing and aggregating land for sustainable planning and land use in Da Lat city and its vicinities 1.3.3.1. Basis for determining research boundaries and scope: Based on (1) the development history of Da Lat city through periods; (2) Planning to expand Da Lat City to 2030 and a vision to 2050; (3) Characteristics of natural conditions. 1.3.3.2. Some specific characteristics in land use and exploitation in Da Lat city and its vicinities Da Lat city and its vicinities have basic characteristics of the mountainous highland urban area, so the characteristics of land use and exploitation in the territory also show these characteristics, such as: - The differentiation of soil cover is diverse and complicated due to the influence of the non-zonal differentiation rules, especially the law of high- belt differentiation and tectonic-geomorphology differentiation, expressed through the system of feralite soils on different types of basement rocks and high belts, creating favorable conditions for the research area to develop a wide variety of agro-forestry crops and form large specialized annual and perennial tree-growing areas on the highlands. - The natural area of the territory is mainly forestry land and agricultural production land. However, the current forest cover in mountainous areas has been strongly reduced, which is mainly caused by deforestation to expand agricultural land. This is also the main conflict in land use exploitation in the research territory. Therefore, the identification of appropriate space, the arrangement of agricultural and forestry production types in a scientific way, not only resolve conflicts in land use exploitation among territorial spaces and meet the objectives of ensuring food security and economic development (providing raw materials for processing and export industries) but also protect land, water, forest resources and protect the natural environment for sustainable territorial development. - Due to the terrain of the plateau and mountains with high slope, the potential soil degradation processes (erosion, washout, landslides, etc.) are very great, areas that lose their forest cover or agricultural production lacking soil protection measures has led to serious soil degradation. - As an area with diverse and increasing types of non-agricultural land use. Therefore, in the orientation of sustainable development of territories, it is necessary to consider the structure and characteristics of specific types of non-agricultural land use in each of those territories. 1.3.3.3. General land evaluation for spatial orientation and sustainable land use solutions in Da Lat city and its vicinities According to the geographic approach, a general land evaluation based on the integration of the results of land classification and evaluation and soil degradation assessment by soil geographic zoning will determine the 10
sustainable land use type for land units in the territory, thereby providing spatial orientation and appropriate land use solutions as a scientific basis for sustainable planning and land use in Da Lat city and its vicinities. From the specific characteristics of land use exploitation in the studied territory, the natural land area as well as the conflicts and contradictions in the territory's land use structure mainly belong to agricultural production space and forestry space, the thesis focuses on researching, proposing orientations and solutions for sustainable land use for these two spaces. At the same time, analyzing the results of land use orientation for agricultural- forestry-urban production spaces by each soil sub-geographic region to propose priority development space orientations for each territory, aiming to organize a sustainable space in Da Lat city and its vicinities. 1.4. Research views and research methods 1.4.1. Research views: Use of specific research perspectives of the integrated natural geography including soil biological perspective, ecological perspective, historical perspective, system perspective, integrated perspective and sustainable development perspective. 1.4.2. Research Methods: Methods of inheritance and integration; Methods of survey and investigation; Methods of analyzing soil physical and chemical properties in the laboratory; Expert methods; Methods of assessing economic efficiency of land use types; Mapping and GIS method; Methods of land evaluation and classification; Methods of soil degradation assessment; Methods of soil geographic zoning. 1.5. Research procedure Study the geographical basis in land use exploition for sustainable planning in Da Lat city and its vicinities - Lam Dong province Define goals and missions Characteristics of arising Determine theoretical basis and geographical conditions - research methods degeneration of soil and land resources in the research area Integrated land evaluation for sustainable land use Land ecaluarion and classification suitable for agriculture and forestry Assess general soil degradation and production determine the degree of degradation on land units Geographic zoning for the research area Proposing orientations for organizing space for sustainable land use Figure 1.5 Diagram of research steps 11
Chapter 2. CHARACTERISTICS OF ARISING GEOGRAPHICAL CONDITIONS - DEGENERATION OF SOIL AND LAND RESOURCES IN DA LAT CITY AND ITS VICINITIES; 2.1. Arising conditions - soil degradation 2.1.1. Geographical location The research area is located in the north of Lam Dong province, including the administrative boundaries of Da Lat city and 4 adjacent districts: Lac Duong, Don Duong, Duc Trong and Lam Ha (referred to as Da Lat and its vicinities). The region has an average altitude above 850m above sea level, with geographical coordinates extending from 11030'27” to 12019'4” North latitude and from 108020'18” to 108043'39” East longitude. The total natural area is 415,101.9 ha, accounting for 42.4% of the province's total natural area. 2.1.2. Geological and mantle rock characteristics 2.1.2.1. Geological characteristics The long history of geological development has left the research area complex geological structure, including ancient sediments, intrusive rocks or ancient eruptions to basalt eruptions and quaternary and tertiary sediments which are younger, divided into 5 main rock groups, including: deposit and metamorphic rocks, granite intrusive rocks, neutral eruptions to weak acids, basalt eruptions and unconsolidated quaternary sediments. 2.1.2.2. Mantle rock characteristics In the law of forming Mantle rock (VPH) of the humid monsoon tropics, the feralitization process (iron and aluminum accumulation) with laterite and laterite - bauxite formations is a key trend. However, due to the natural conditions in which the basement rock and topography play the most important role, the research area has weathered products including: VPH saprolite, silicite, sialite, sialferite, ferosialite, alferite. 2.1.3. Topographic and geomorphological conditions The topography of the research area consists of mountainous areas (medium mountains, high mountains), highlands and plains. The popular terrain orientation is Northeast - Southwest. The terrain is clearly hierarchical, lower from the North to the South, including: High level: is the average high mountain range (1000 - 1500 m), completely up to the peaks above 2000m (Chu Yang Sin 2,405 m, Lang Biang 2,163 m); Low level are strong wavy hill-shaped plateaus, consisting of two different surfaces of about 500m. The above ground surface is 1500m high and the below surface is 850-1000m high. 2.1.4. Climate and hydrological characteristics 2.1.4.1. Climate characteristics The study area is characterized by a tropical monsoon tropical climate, strongly influenced by the monsoon tropical circulation and high belt. The differentiate of the terrain has divided into climatic regions with different characteristics, it can be divided into 2 regions: (1) Climate zone of Da Lat 12
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 3 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 7 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 8 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 3 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 3. 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) Area (ha) LMU quantity Ratio (%) 1 1.000 126,968.7 75 31.0 Total land area 410,103.1 1,129 98.8 Rivers, streams, lakes 4,998.8 1.2 Total natural area 415,101.9 100.0 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 4 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 2 evaluation methods (limited conditions, dominant factors) and 4 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 Levels of suitablity Total Very Less Not suitable LUTs Area / Ratio Suitable natural suitable suitable (N) (S2) land area (S1) (S3) Ha 5,336.9 16,256.0 7,467.3 381,042.9 410,103.1 1. Rice % Natural 1.3 4.0 1.8 92.9 100.0 land area 2. Cash Ha 8,588.3 71,999.1 14,953.7 314,562.0 410,103.1 crops % Natural (vegetables, 2.1 17.2 3.6 77.1 100.0 land area flowers) Ha 2,417.8 29,308.9 56,677.1 321,699.3 410,103.1 3. Robusta % Natural coffee 0.6 7.1 13.8 78.4 100.0 land area Ha - 52,760.8 111,144.3 246,197.9 410,103.1 4. Arabica % Natural coffee - 12.9 27.1 60.0 100.0 land area 15
Ha - 44,677.7 130,960.3 234,465.1 410,103.1 5. Tea % Natural - 10.9 31.9 57.2 100.0 land area Ha 14,798.4 30,910.2 25,753.0 338,640.6 410,103.1 6. Mulberry % Natural trees 3.6 7.5 6.3 82.6 100.0 land area Ha 12,360.1 50,169.6 104,992.8 242,580.6 410,103.1 7. Fruit trees % Natural 3.0 12.2 25.6 59.2 100.0 land area Ha 7,330.5 121,898.1 227,290.9 53,583.5 410,103.1 8. Three- % Natural leave pines 1.8 29.7 55.4 13.1 100.0 land area 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 7 norms under 4 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 3 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 3 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 3 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 4. 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 Zoning norms 1 Region 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. 2 Sub-region 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 5 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 3 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 5 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 2 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 4 sub-regions, of which the sub- region 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 5 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 sub- regions. 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