Initial assessment of soil improvement of acacia trees planted in the mining area of tan rai lam dong province

ACKNOWLEDGEMENTS Be consented of the university, of forest resources and the environmentmanagement faculty , I perform thesis topic: Initial assessment of soil improvement of acacia trees planted in the area to mining Tan Rai - Lam Dong On the occasion of completed graduation thesis, I would like to express deep thanks to: Assoc Prof Tran QuangBaowho has guided and helped me in the process of implementation and completion of this thesis Thanks toNhan Co environment company for has created an opportunity to help me perform this study Due to my limited expertise and practical and also in the limited time taken up the graduation thesis inevitable shortcomings Glasses look forward to the comments of the teachers to get more complete thesis Sincerely thank! Hanoi, September 25, 2015 Student Duong Van Huy CONTENTS ABSTRACT 1 INTRODUCTION STUDY SITE 2.1 Natural conditions 2.1.1 Geographical location 2.1.2 Topography 2.1.3 Climate characteristics 2.1.4 Characteristics natural plant systems 2.2 Socio-Economic Conditions 2.2.1 Economic characteristics humanities 2.2.2 Traffic characteristics - communication 3 OBJECTIVES AND SCOPE STUDY 3.1 Goals 3.2 Scope of the study 4 METHODS 5 RESULT AND DISCUSSIONS 11 5.1 Environmental characteristics of the land after mining bauxite 11 5.2 Characteristic of acacia growing on the site after bauxite exploiting inTanRai 12 5.3 Comparing soil characteristics ofAcacia plantation at different ages 15 5.4 Recommendations to strengthen the resilience of the land after bauxite mining 25 CONCLUSIONS 26 REFERENCES 27 ABSTRACT The study have been carrying out in Tan Rai bauxite - Lam DongProvince, I have some assessment of the environmental status here I completed this research with practical observations, collect data and analyze soil samples These goals are completed include: (1) assess the impact of mining on the environment, (2) - The afforestation models-for soil improvement , (3)-Impact of models Acacia planting to environment The implementation of this study is extremely important Because, the miningactivities have destroyed an-huge areaof-environment Over the general assessment,-will help to find the better measures to improve the environment and to-restore vegetation.In this study also shows the advantages of Acacia auriculiformis for environmental rehabilitation.It is required to quickly implement projects of acacia plantationto minimize the impact of mining on the soil environment INTRODUCTION Vietnam is a country with great potential for bauxite in the region and around the world Bauxite oredistributed both in the north and the south ofVietNam, but the largest concentration in the southern central highlands Total bauxite ore reserves and resources were identified about 5.5 billion tons forecast in which the North is about 91 million tons, the southern region of about 5.4 billion tones With bauxite resources were identified above, projects construction Bauxite Mining - Aluminum Lam Dong will play a very important role for the economy and the process of industrialization of the country As industry alumina aluminum is formed which will reduce the amount of funds used to import large as today However, the project activities have caused a lot of negative impacts on the natural environment and social environment The topography of the mines will be changed much The surface layer and the layer side of the mines after the mining are not covered by vegetationand become barren Therefore, in the rainy season,the mining areas occurs erosion and a lot of sedimentation flow into river systems Mining areas activities will generate dust which affected residential areassurrounding and it degraded environmental landscape.To minimize the environmental impacts of mining activities, the mining project must implement its’ commitment of environmental restoration after mining Moreover, they need to plant trees to greening the entire areas tailings and mines after mining They have plantedacacia, coffee, tea and rubbertreesfor soil improvement, anti-dust, preventing the overflow surface erosion and improve ecological environment Up to now almost of the areas after mining was conducting plant Acacia The age of the Acacia is more thanone years old Important or requirement of environment rehabilitationafter mining , the authors propose to implement the research project: "The initial assessment of soil improvement of acacia trees planted in the mining areasof Tan Rai - Lam Dong Province ” STUDY SITE 2.1 Natural conditions 2.1.1 Geographical location Tan Rai bauxite mining area located in the territory of communesLocThang, PhuLoc and NgaiLocinBao Lam district, Lam Dong province The mine is far from theBaoLoc city20 kilometers in the northeast Geographical coordinates of mining area: 11038'08 '' to 11041'56 'degree north latitude.107049'54 '' to 107053'12 'east longitude 2.1.2 Topography The mine is belonging to the eastern part of the plateau BaoLoc - Di Linh, relatively flat terrain sloping from northeast to southwest Mine divided area into relatively flat regionswith elevation 30m - 80m, branching extend or narrow (100 m - 400 m) The peneplainterrain is very favorable for the bauxite laterite development and creation Most bauxite is development on peaks 2.1.3 Climate characteristics According to the document meteorological observation recent years ago (since 19901998), in the town of- BaoLoc average annual temperature is 21,70 C, total average rainfall is 2356.5 mm/year.The climate is divided into two seasons: the dry season from November to April the following year (20,50C temperature and total rainfall is 436 mm) and the rainy season from May to October (22,10C temperature and total rainfall is 2,248 mm) The climate is characterized by tropical monsoon region, with the rainy season and dry season 2.1.4 Characteristics natural plant systems Most of the areas is covered by pine(Pinuslatteri) forests andmixed plantations of coffee tea Currently, a few pine forests are remaining and- a lot of areas are being cleared to establish industrial tree gardens, especially in the hills along the edge where it meets the water resource, riparian and lowland 2.2 Socio-Economic Conditions 2.2.1 Economic characteristics humanities The area is surrounded Bao Lam Tan Rai bauxite mine has a population of about 100,000 people, mainly ethnic Kinh, Koho, Chauma, Tay, Nung Population density is about 66 people / km2, distributed unevenly The majority of people living in hamlets formed residing along the provincial road, the population is mainly concentrated in LocThang town Elsewhere the population clusters of the migrant cultivate and deforest Economy mainly is depended on agriculture and forestry In agriculture, they are mainly grows coffee and tea In forestry,they are logging, turpentine and currently the develops agroforestry models There is only some small areas is growing in economic They are mainly based on pulp processing plants, fertilizer manufacturing factories, the tea processing factory, weaver, the enterprises of building materials and minor mechanical repairs Conditions of political security and social order in the region is maintained well and is increasingly consolidated and developed 2.2.2 Traffic characteristics - communication -Tan Rai bauxite mines traffic conditions is very convenient because the mines is near Highway 20, Ho Chi Minh City to Da Lat LocThang town newly formed located adjacent to the mine The infrastructure around the mining areas has been finalized - Regarding air traffic: mines located about 100km from Lien Khuong Airport Lien Khuong airport in existing routes: Hanoi - Da Lat and Ho Chi Minh City - Da Lat - Regarding land road traffic: From Ho Chi Minh City, heavy trucks along Highway 20 through the town of BaoLoc, LocThang town to Tan Rai and from PhanThiet -town truck along Highway 8B throughDiLinh Tan Rai to very favorable -Regarding communication: mobile relay station of all providers formobile communication services have been installing in the region 3 OBJECTIVES AND SCOPE STUDY 3.1 Goals - Assess the current state of the environmental characteristics of the land in the areas after mining bauxite - Analyze growth characteristic of acacia planted forenvironmental rehabilitation after mining bauxite in Tan Rai - Assess soilcharacteristics under planted acacia after mining bauxite - Assess impacts of the acacia plantation on soil improvementafter mining bauxite - Propose recommendations to enhance the resilience of the land after mining bauxite 3.2 Scope of the study This study was conducted in the bauxite mining areas ofTan Rai - Lam Dong province Object of study is newly acacia plantation after mining Acacia auriculiformiswas selected for planting models after mining Acacia auriculiformis is pioneer trees to restore the soil environment and regeneration of native tree species broadleaf Acacia auriculiformis is a species of legume Thai Van Trung[6] was the first discovery about-Acacia auriculiformis- grow on poor soils, erosion, drying up, especially kill thatched grass,─closed canopy quickly─ if planted thick,─and it is important Acacia auriculiformis have roots which have nitrogen-fixing nodules was renovated and restored under forest land The study area is the Tan Rai bauxite mining areas, focusing on the area planted Acacia auriculiformisplantation forests Scope of the study:-Focusing on the impacts of the- acacia plantationmodel on the environment and compare with thatof the other crops in the study areas 4 METHODS + Collect secondary data from mining project in Tan Rai bauxite + Carry out field research to collect primary data for acacia growing from surveyed plots and for soil characteristics from soil samples The primary data collection was designed for acacia plantations of different ages (year and year 5) + Settingstandard plots: Sixtypical sample plots with an area of 100 m2 standard (10m x 10m)has been setting up Establish typical sample plots at Acacia years old In which determine the number of tree, trunk diameter, tree height Height trunk is denoted in words H, measured in meters Tree height is denoted in words Hvn, (m) Trunk diameter is denoted in words D, measured in centimeters In measuring tree trunk diameter is measured in different positions: m, 1.3 m from the ground Establishing similar sample plots in Acacia years old, which determine the number of trees, trunk diameter, tree height The instruments for measuring diameter are calipers or tape measure Using calipers measured in 2-dimensional calculation of the average value Use a tape measure to measure the circumference of the trunk On special ruler has calculated from the perimeter to diameter Tape measure diameter usually calculated by dividing perimeter divided by 3.1416 Placements to measure the diameter usually include original diameter D0, diameter at breast height D1,3 Height is an important factor to reflect the size of the tree With less than meter trees often medication bamboo has incised dm With meter high trees, high measurement using geometric principles, or trigonometry Some commonly used rulercurrently Blume - leiss, Suunto + Data analysis: - Using WORD and EXCEL - Analysis of soil samples Take soil samples in each sample plot On the typical sample plots obtained 36 soil samples Soil samples were taken at two different soil layers: 1st layer from 0-20cm, 2nd layer from 21-40cm Soil samples were analyzed in laboratory to identify some Physical, chemical characteristics: Table 4.1 Name of factor andmethod Number Factor Method pHKCL pH - meter Organic matter Walkley - Black Total Nitrogen Kjeldahl Total Phosphorus colorimetric Total Potassium Flame Photometer Digestible phosphorus Ônian Digestible Potassium Flame Photometer Calcium exchange Atomic Absorption Magnesium exchange Atomic Absorption 10 AL+++ Sokolop 11 Mechanical composition Pipet 12 Bulk density Test tubes 13 Density Picnomet 14 Porosity Calculated according to the formula P (%) = (1-D / d) x 100 The general concept of the physical and mechanical properties of soil: The soil has some physical properties and mechanical properties mainly as density, bulk density, porosity, adhesive properties, ductility, hardness, resistance and so on These properties are usually determined by the mineral composition (primeval, secondary), the composition of particles (sand, silt andclay), the composition of organic matter in the soil and coherence between components in order to create the texture of the soil  Density of soil Density of soil is the ratio of the mass of a unit volume of residential land solid state, drying up the soil particles together tightly than the volume of the same volume of water at temperatures 40C.[2]  To calculate the density of soil is followsthe formula: d = P / P1 Which in: d - Density of soil P- Volume soil particles (dried, ranked Nazis together and no space air gap) in a determined volume (usually measured in g / cm3) P1 - The volume of water stored in the same volume in terms T0: 40C (g / cm3) Density of soil is determined primarily by the minerals primeval, secondary and organic matter content in the soil In general, because the percentage of organic matter in soils is usually not large, the proportion of land will depend mainly on the mineral composition of the soil Based on the proportion of land, Katrinski issued a joint assessment to determine the proportion of cultivated land is as follows : Figure 5.3.Soil surface after mining prepared for reforestation (Source: Field survey) To assess the role of acacia plantation forest on soil improvement The study have measured growth characteristics of acacia planted after year old and years on the bauxite exploited site Figure5.4.Acacia year old Figure 5.5 Acacia years old (Source: Field survey) The growth factors are shown in the following table 13 Table 5.1.Data of Acacia years old Area Number The average The average tree Survival (m2) of trees diameter D0(cm) height,Hvn(m) rate( %) 100 23 1.2 0.9 92 100 21 1.09 0.9 84 100 24 1.3 1.1 96 Number Areas 1-year-old tree: because small trees should not proceed measured diameter at breast height D1,3.In the sample plots,average diameter from 1.09 to 1.3 ( cm) ,height from 0.9 - 1.1(m) Trees were underdeveloped Table 5.2.Data of acacia years old Area The average diameter tree height D1,3(cm) ,Hvn(m) Number Number ( m2) The average Survival rate of trees (%) 100 24 10.5 8.2 96 100 25 11.2 8.5 100 100 24 10.1 7.9 96 In the sample plots, average diameter from 10.5 to 11.2 (cm) ,height from 7.9 – 8.5(m) Plants grow well and survival rate is high 14 105 100 100 95 96 96 96 92 Acacia years old 90 84 85 Acacia years old 80 75 The chart 5.1.Comparison of survival rates between the areas Survival rate in- Acacia years old higher than- Acacia year old because in areas Acacia 5-year-old- are well cared and were replantedthe dead trees In general, the development of the Acacia is quite fast With the advantage of rapid growth, high survival rate, Acacia trees were planted to improve soil on most of the areas Acacia give efficiency is relatively high than coffee plantations, tea and rubber The areas planted Acacia on large area somewhat limiting soil erosion Figure 5.6.Rubber trees Figure 5.7.Coffee treesFigure (Source: Field survey) 5.3 Comparing soil characteristics ofAcacia plantation at different ages Comparison of the physical elements in areas • Results of soil sample analysis are shown in table and table 15 5.8 Tea trees Table 5.3 Data of physical elements in acacia 1years old Bulk density Layer Indicators Porosity Density (g/cm3) (%) Number of samples 9 Layer (0- Minimum 0.73 2.62 72 20cm) Maximum 1.12 2.71 59 The average value 0.93 2.67 65 Number of samples 9 Minimum 0.8 2.59 70 Maximum 1.16 2.65 56 The average value 0.98 2.62 63 Layer (2140cm) Table 5.4 Data of physical elements in acacia 5years old Bulk density Layer Indicatiors Porosity Density (g/cm3) Layer (0-20cm) Layer (21-40cm) (%) Number of samples 9 Minimum 0.64 2.54 75 Maximum 1.01 2.59 61 The average value 0.83 2.56 68 Number of samples 9 Minimum 0.68 2.47 74 Maximum 1.03 2.55 60 The average value 0.86 2.51 66 16 80 68 65 60 Acacia year old 40 Acacia years old 20 0.93 0.83 2.67 2.56 Bulk density (g/cm3) Density Porosity (%) Chart 5.2.Comparison of soil physical elements in layer In general at Acacia planting land areas were quite well on volume of humus and high porosity It is favorable to plant growth In these figures, I assessed the physical properties of the two regions At Acacia areas years old has density and proportion smaller than Acacia areas years old Besides Acacia areas years old has high porosity Prove the surface soil at years old Acacia is better 70 63 66 60 50 40 Acacia year old 30 Acacia years old 20 10 0.98 0.86 2.62 2.51 Bulk density (g/cm3) Density Porosity (%) Chart 5.3.Comparison of soil physical elements in layer At layer 2, generally factors are still showing good quality soil Density of soil was identified as soil with humus average Because volume of humus decreases with depth, it 17 increases bulk density and porosity reduced.The data shows lower soil layer of─Acacia areas years old─better Table 5.5.The soil texture Type of soil Sand (%) Silt (%) Clay (%) Acacia year old 25.26 35.48 39.26 Acacia years old 22.44 37.98 39.58 In general, soil in the study area has average soil texture is quite suitable for a variety of crops, ease of fertilizer and soil improvement.[3]  Compare the chemical properties of the soil in the study area Chemical properties of soil are shown in table and 10 18 Table 5.6.The chemical elements of the soil in acacia areas year old pHK Layer cations exchange (me/100g digest (mg/100g soil) soil) Total (%) OM Indicators CL Fertilizer easy to (%) N P2O5 K2O P2O5 K2O Ca+ Mg++ Al+++ Layer Number of sample 18 18 18 18 18 18 18 18 18 18 (0-20cm) Value 4.66 3.76 0.23 0.26 0.108 18.99 6.41 3.68 0.68 0.36 Layer Number of sample 18 18 18 18 18 18 18 18 18 18 Value 4.69 2.49 0.18 0.22 0.09 8.45 5.30 3.38 0.48 0.24 (21-40cm) 19 Table 5.7.The chemical elements of the soil in acacia areas year old Fertilizer easy to digest Layer Layer (020cm) 40cm OM L (%) Total (%) cations exchange (me/100g soil) mg/100g soil) Indicators N P2O5 K2O P2O5 K2O Ca++ Mg++ Al+++ Number of 18 18 18 18 18 18 18 18 18 18 4.34 4.22 0.31 0.39 0.98 23.67 7.85 3.21 0.45 0.27 18 18 18 18 18 18 18 18 18 18 4.41 3.55 0.25 0.28 0.05 12.37 5.78 3.02 0.33 0.18 sample Value Layer2 (21- pHKc Number of sample Value 20 Chart 5.4.Compares the- layer between the two areas 23.67 25 Acacia areas year old Acacia areas years old 18.99 20 15 10 6.41 4.66 4.34 7.85 3.76 4.22 0.23 0.31 0.26 0.39 N(%) P2O5(%) 0.108 0.98 pH OM(%) K2O(%) 21 P2O5 (mg/100g soil) K2O((mg/100g soil) Chart 5.5.Compares the - layer between the two areas 14 12.37 12 Acacia areas year old Acacia areas years old 10 8.45 5.3 4.69 4.41 5.78 3.55 2.49 0.18 0.25 0.22 0.28 0.09 0.05 N(%) P2O5(%) K2O(%) pHKCL OM (%) 22 P2O5(mg/100gsoil) K2O(mg/100g soil) Through figures and graphs we can make comparisons and comment on two areas  Soil acidity:  In the area of Acacia year old Value pHKcl instructed exchange acidity of the soil environment Data analysis showed that soil acidity exchange Acacia areas year old in Tan Rai-Lam Dong bauxite valuable first layer is 4.66, the second layeris 4.69 Compared with the land under forest pHKClwas good, there was no difference (Nguyen Van Toan et al., 2005) This value is in the range appropriate for Acacia  In the Acacia areas years old Value pHKCL at 1st layer- from 0-20cm is 4.34, 2nd layer from 21-40cm is 4.41.pHKClvalue have the uptrend gradually from top to bottom , this phenomenon is explained by the process of leaching alkaline and alkaline cations at the surface to the lower level and is accumulated in the depths makes pH of the- layer higherthan layer1  Organic matter in the soil:  In the Acacia- areas year old The analysis results showed that the organic matter content of the surface layer is relatively high at OM = 3.76% However, total organic content in the layer quickly reduce OM = 2.49% In the Acacia areas years old higher than humus areas acacia year old Layer1 OM = 4:22%- ,-Layer OM = 3.55 % The humus content decreases with depth This may explain by Acacia leaves’ fall and decompose quickly create a significant amount of soil humus  Compare the total nitrogen content: Total nitrogen content in the acacia areas years old higher than- acacia areas year old 23 We see the total nitrogen content of the soil in two areas as moderately to rich, compared with the layer 1, total nitrogen content in the layer significantly reduced organic content due to rapid decline  Compare total phosphorus and easy digest phosphorus: The analysis results in two tables showing the total phosphorus content is quite rich in whole soil (> 0.13% P2O5) and rapid decrease in depth The number of easy digest phosphorus tends to be markedly improved in acacia areas years old The increase easy to digest phosphorus in the soil is due to the investments and the satisfy the requirements of phosphorus more easy to digest phosphorus can thus satisfy the requirements for Acacia  Compare total Potassium and easy digest potassium: The results of analysis of soil potassium total showed very poor soil potassium of the potassium in the soil degraded due to many reasons Firstly because the sources for the soil,which is due to the flexibility potassium than many other factors in tropical conditions and demand very high potassium of Acacia  Calcium and magnesium exchange: The analysis results showed that the amount of land with Ca ++, Mg ++ exchange relatively poor Status low cations exchange takes place not only in soil developed on basalt, but also occur quite common in our country's mountains Where erosion occurs, wash away the strong cations exchange, brass time for this process is the accumulation of iron, aluminum is very typical.[2]  Aluminum (Al +++): The level of dissolved aluminum depends on the pH value Al +++ concentrations rapidly decreased when pHKCl increase.[4] 24 5.4 Recommendations to strengthen the resilience of the land after bauxite mining Because the mining process is implemented in a long time, annual mining area of 50 - 70 ha,need to perform regreening andreduce soil erosion after miningTherefore, investors of Rehabilitation Environment after mining projectrecommend to the competent authorities about the environment as follows: - For the rehabilitation and restoration work for the mining environment as every years (3 years of planting and care of trees cent) will confirm the workload has been completed with the authorities having jurisdiction - Need to apply advanced technology to the processing of sludge for the environment, because Vietnam has a tropical climate, frequently have very large rains, water can still flow through the dam, it reeled in the toxic waste into soils, rivers and streams downstream, causing environmental pollution on a large scale - Adding potassium needed for the areas crops because of potassiumvery poordue to the nature of soil - Should planting pine interspersedwithacacia becauseacaciafast-growing The development of acacia will help protect pine and the layer soil under forest canopyof acacia provide nutrient for pine.Therefore it will ensure the development of pine and bring more efficiency in soil improvement - Quickly planted in the areas ended harnessing to greening barren land, land improvement, dustproof, prevent rainwater runoff phenomena on the surface erosion and improve ecological environment 25 CONCLUSIONS The bauxite mining in Tan Rai - Lam Dong cause negative impacts on the environment The terrain is altered, lost vegetation, soil erosion, etc.Need to have quick remedial measures, especially in restoring vegetation Overall, the land improvement after mining in Tan Rai bauxite - Lam Dong focused on developing traits acacia for good in the land improvement The areas planted fastgrowing Acacia high survival rate than other species to meet demand rapidly greening barren soil here The plantation in the mining areas is promoting planting acacia because acacia has characteristic for soil improvement The areas has been renovatedproperties of chemically and physics The soil has good factors can plant many different species pH value from about 4.66 - 4.69 inthe area of acacia 1- year - oldand acacia about 4.34- 4.41 in the area of acacia -5 years- old The value of pH not exceed the allowable value Humus content at two area is high.The lowest value is 2.49 and the highest value is 4.22.Soil properties very poorpotassium, the result of two areas also have potassiumcontent very little In surface soil highest value obtained was 0.108 (%) The soil layer 20-40 (cm) the value reduced and the value only 0.09(%).The value of nitrogen content quite high The values obtained fromsamples ranged from 0.18 -0.31 (%).Phosphorusvalues alsoin high The result from 0.22 - 0.39(%) The reason is thatability to fix nitrogen of acaciawill provide nutrients to the land Offset the amount of land nutrients have being washed away The acacia forest would be a prerequisite for the development of different forests Continue greening of the area was mining andcombining the trees must conform with planted under the canopy such as pine Contribute to soil improvement, prevent erosion and boosting the biodiversity of the area 26 REFERENCES Chijoke, E.O, 1980, Impact on soil of fast - growing species in lowland humid tropics FAO forestry paper, 21ROME Vu Anh Tu Nguyen Van Toan (2014): PHYSICAL AND CHEMICAL PROPERTIES OF BASALT SOIL Journal of Science and Development 2015 Nguyen The Dung (Editor).Dang Van Minh.Nguyen The Hung (2007): PHYSICAL PROPERTIES OF SOIL.– 2007, Ha Noi PhanTuan Trieu(2009): SOIL RESOURCES AND ENVIRONMENT.–July2009,Binh Duong K Ymamoto, NT Nhan (2000):Report on the basic properties and utilisation of fast growing plantation species in Vietnam; A auriculiformis, Acacia mangium, and their hybrid L.W Jacques (1998): Potential use of Acasia species as raw material for pulp and paper industry, In Proceedings of International Conference on Acacia species – Wood properties and utilisation, 20-31, 16-18 March 1998, Penang, Malaysia NguyễnĐìnhHịe(2009): Environmental issues related to bauxite mining Highlands 27