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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Effectiveness of cover crops in preventing soil erosion

Shulkcum, Edward January 1930 (has links)
M.S.
102

Soil conservation in vocational agriculture: organized subject matter on the engineering units in soil conservation for use of teachers and students of vocational agriculture in Virginia (and West Virginia)

Saufley, G. M. January 1945 (has links)
Problems in soil conservation are becoming increasingly important to the farmers of Virginia, West Virginia, and the nation. Much valuable material is available on the subject, but only a small part of it is suitable for use in vocational classes. There is a definite need for selection and organization of material in this field. This study has been made with the following objectives: 1. To develop reference material on Engineering unite in Soil Conservation for the use of boys in vocational agriculture classes. 2. To develope a job analysis and a list of references on these Engineering unite to·be used by teachers of Vocational Agriculture. / M.S.
103

Teaching resource use education in an elementary school through the planning of a resource unit in soil conservation

Jackson, Charles G. Unknown Date (has links)
No description available.
104

Land degradation and rehabilitation in severely eroded granitic area of south China: a case study of Deqing.

January 1991 (has links)
by Choi Chi Hoi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1991. / Bibliography: leaves 171-178. / ABSTRACT --- p.iii / ACKNOWLEDGMENTS --- p.v / TABLE OF CONTENT --- p.vi / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xii / LIST OF PHOTOS --- p.xiv / LIST OF APPENDICES --- p.xvi / Chapter I --- INTRODUCTION / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Objectives --- p.6 / Chapter 1.3 --- Uniqueness and Significance of the Study --- p.7 / Chapter 1.4 --- Some Key Concepts --- p.9 / Chapter 1.5 --- Organization of the Thesis --- p.11 / Chapter II --- THE STUDY AREA / Chapter 2.1 --- Selection of the Study Area --- p.12 / Chapter 2.2 --- The Physical and Socio-Economic Environment of the Deqing County --- p.17 / Chapter 2.2.1 --- Location --- p.17 / Chapter 2.2.2 --- Climate --- p.17 / Chapter 2.2.3 --- Geology and Landform --- p.18 / Chapter 2.2.4 --- Vegetation --- p.18 / Chapter 2.2.5 --- Population and Economic Activities --- p.19 / Chapter 2.2.6 --- History of Soil Erosion and Conservation --- p.21 / Chapter 2.3 --- The Shenchong Basin --- p.26 / Chapter 2.4 --- The Lichong Basin --- p.28 / Chapter 2.5 --- The Resource Base of Deqing --- p.30 / Chapter III --- METHODOLOGY --- p.34 / Chapter 3.1 --- Conceptual Considerations --- p.34 / Chapter 3.2 --- Land Degradation Processes --- p.35 / Chapter 3.2.1 --- Nutrient Loss from Hillslopes --- p.38 / Chapter 3.2.2 --- Iron Toxicity --- p.43 / Chapter 3.2.3 --- Properties and Nutrient Status of Rehabilitated Soils --- p.44 / Chapter 3.2.4 --- Methods of Chemical Analysis of Water and Soil Samples --- p.49 / Chapter 3.3 --- Cost-Benefit Analysis of Rehabilitation Measures --- p.50 / Chapter 3.4 --- Problems and Limitations --- p.54 / Chapter IV --- LAND DEGRADATION: PROCESSES AND PROBLEMS --- p.56 / Chapter 4.1 --- Landscape Changes in a Severely Eroded Granitic Area --- p.56 / Chapter 4.2 --- Land Degradation Processes 一 On-site Effects --- p.60 / Chapter 4.2.1 --- Soil Loss on the Hillsides --- p.60 / Chapter 4.2.2 --- Loss of productivity on the Hillsides --- p.64 / Chapter 4.3 --- Land Degradation Process - Off-Site Effects --- p.70 / Chapter 4.3.1 --- Burial of Agricultural Land Beneath Alluvial Fans --- p.70 / Chapter 4.3.2 --- Concentration of Dissolved Iron in Sub-surface Water --- p.74 / Chapter 4.4 --- Concluding Remarks --- p.78 / Chapter V --- COST-EFFECTIVENESS OF EROSION CONTROL MEASURES THEORETICAL CONSIDERATIONS --- p.80 / Chapter 5.1 --- Introduction --- p.80 / Chapter 5.2 --- Economic-Biophysical Management Linkages in the Shenchong Basin --- p.80 / Chapter 5.3 --- Range of Erosion Control/Land Use Options --- p.83 / Chapter 5.4 --- Methodology --- p.83 / Chapter 5.4.1 --- Data Sources --- p.85 / Chapter 5.4.2 --- Economic Valuation Techniques --- p.85 / Chapter 5.5 --- Cost-Effectiveness Evaluation of Erosion- Control Measures --- p.87 / Chapter 5.5.1 --- Option 1 - Hillsides are Maintained Under Dense Fern and Tree Cover and No Use is Permitted --- p.88 / Chapter 5.5.2 --- Option 2 : Slope - Maintaining Dense Vegetation Cover but Permitting Sustained Yield Harvesting of Fern for Fuel and Resin and Timber Production --- p.90 / Chapter 5.5.3 --- Option 3 : Slope - Building Terraces on Hillslopes --- p.92 / Chapter 5.5.4 --- Option 4 : Slope - No Erosion Control Measures --- p.94 / Chapter 5.5.5 --- Option 5 : Slope - Conversion from Fern and Woodland to Baji and Yu Gui Crops --- p.94 / Chapter 5.5.6 --- Option 6 - Small Check Dams Constructed to Control Gully Erosion --- p.94 / Chapter 5.5.7 --- Option 7 : Gully - Large Check Dams --- p.97 / Chapter 5.5.8 --- Option 8 : Gully - Biological Dams --- p.98 / Chapter 5.5.9 --- Option 9 : Gully - Infilling of Gullies --- p.99 / Chapter 5.5.10 --- Option 10 : gully - No Erosion Control --- p.100 / Chapter 5.6 --- Policy Implications --- p.100 / Chapter 5.7 --- Policy Optimization With Multiple-Objective Decision Modeling --- p.102 / Chapter VI --- REHABILITATION PROGRAM AT SHENCHONG AND LICHONG RECONSIDERED --- p.107 / Chapter 6.1 --- Introduction --- p.107 / Chapter 6.2 --- Land Rehabilitation at Shenchong --- p.107 / Chapter 6.3 --- Land Rehabilitation at Lichong --- p.111 / Chapter 6.4 --- Ecological Considerations --- p.119 / Chapter 6.5 --- Agricultural Considerations --- p.124 / Chapter 6.5.1 --- Chemical Soil Properties --- p.126 / Chapter 6.5.2 --- Physical Soil Property --- p.135 / Chapter 6.6 --- Economic Considerations --- p.143 / Chapter 6.6.1 --- Costs and Benefits of Rehabilitation Activities --- p.144 / Chapter 6.6.2 --- Sustainability of the Rehabilitation Programs --- p.146 / Chapter 6.6.3 --- Distribution of Costs and Benefits over Time --- p.148 / Chapter 6.7 --- Institutional Considerations --- p.151 / Chapter 6.7.1 --- Rural Economic Reform --- p.152 / Chapter 6.7.2 --- Institution Set-up of the Two Brigades --- p.153 / Chapter 6.7.3 --- Distribution of Cost and Benefits --- p.154 / Chapter 6.7.4 --- Risk Management --- p.155 / Chapter 6.7.5 --- Land Use Planning --- p.156 / Chapter 6.7.6 --- Motivation --- p.157 / Chapter 6.7.7 --- The Search for Solution --- p.159 / Chapter VII --- CONCLUSION --- p.162 / Chapter 7.1 --- Introduction --- p.162 / Chapter 7.2 --- Discussion --- p.166 / BIBLIOGRAPHY --- p.171 / APPENDICES --- p.179
105

The Role of Rainfed Farm Ponds in Sustaining Agriculture and Soil Conservation in the Dry High Valley Region of Cochabamba, Bolivia: Design Considerations and Post Impoundment Analysis

Kuiper, John R. 08 1900 (has links)
Lack of sufficient water for irrigation is a major problem in and around the valleys surrounding the town of Aiquile, Cochabamba Bolivia. In addition, much of the region is undergoing desertification compounded by drought, deforestation, bad traditional agricultural practices, over grazing and a "torrential" rainfall pattern leading to severe soil erosion and low agricultural production. Between 1992 and 1994, the author constructed a network of 24 small, mostly rainfed farm ponds to increase agricultural production and alleviate soil erosion and land-use problems by improving cover conditions. A 5-year post-impoundment analysis was carried out in 1998. The analysis examined current pond conditions, design criteria, irrigation water / crop production increases and the alleviation of land-use problems. Current pond conditions fell into four distinct categories with only 25 percent of the ponds being deemed as "functioning well." The project increased irrigation in the region and improved cover conditions in 66 percent of the pond sites.
106

Early ecosystem restoration in Hong Kong: a case study of the Tai Tong East Borrow Area.

January 1997 (has links)
by Tsang Po-yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 173-191). / Abstract --- p.i / Acknowledgements --- p.iii / List of Tables --- p.iv / List of Figures --- p.v / List of Plates --- p.vi / List of Appendices --- p.vii / Chapter CHAPTER 1 --- INTRODUCTION / Introduction --- p.1 / Chapter 1.2 --- Conceptual framework --- p.3 / Chapter 1.3 --- Objectives --- p.15 / Chapter 1.4 --- Significance and scope of study --- p.17 / Chapter 1.5 --- Organization of the thesis --- p.18 / Chapter CHAPTER 2 --- STUDY AREA / Chapter 2.1 --- Location --- p.20 / Chapter 2.2 --- Climate --- p.23 / Chapter 2.3 --- Geology --- p.25 / Chapter 2.4 --- Soils --- p.26 / Chapter 2.5 --- Vegetation --- p.27 / Chapter 2.6 --- Restoration and floristic composition of the rehabilitated communities --- p.29 / Chapter 2.7 --- Post-planting maintenance of the rehabilitated communities --- p.31 / Chapter CHAPTER 3 --- RESTORATION OF SOIL CHEMICAL PROPERTIES / Chapter 3.1 --- Introduction --- p.33 / Chapter 3.2 --- Methodology --- p.37 / Chapter 3.2.1 --- Sampling --- p.37 / Chapter 3.2.2 --- Soil reaction --- p.37 / Chapter 3.2.3 --- Organic carbon --- p.37 / Chapter 3.2.4 --- Total Kjeldahl nitrogen (TKN) --- p.38 / Chapter 3.2.5 --- Mineral nitrogen (ammonium and nitrate nitrogen) --- p.38 / Chapter 3.2.6 --- Total phosphorus --- p.39 / Chapter 3.2.7 --- Available phosphorus --- p.39 / Chapter 3.2.8 --- Exchangeable cations --- p.39 / Chapter 3.2.9 --- Exchangeable A1 and H --- p.40 / Chapter 3.2.10 --- Carbon : nitrogen ratio --- p.40 / Chapter 3.3 --- Statistical analysis --- p.40 / Chapter 3.4 --- Results --- p.41 / Chapter 3.4.1 --- Chemical properties of the newly excavated soil --- p.41 / Chapter 3.4.2 --- Effect of rehabilitated communities on soil chemical properties --- p.42 / Chapter 3.4.2.1 --- Soil reaction and exchangeable acidity --- p.42 / Chapter 3.4.2.2 --- Organic matter and C:N ratio --- p.43 / Chapter 3.4.2.3 --- Total Kjeldahl N and mineral N --- p.43 / Chapter 3.4.2.4 --- Total and available phosphorus --- p.44 / Chapter 3.4.2.5 --- Nutrient cations --- p.44 / Chapter 3.4.3 --- Intra-layer differences of soil properties --- p.44 / Chapter 3.5 --- Discussion --- p.46 / Chapter 3.5.1 --- Properties of granitic soils awaiting restoration --- p.46 / Chapter 3.5.2 --- Effect of rehabilitated communities on soil acidity --- p.49 / Chapter 3.5.3 --- "Effect of rehabilitated communities on SOM, N and P" --- p.51 / Chapter 3.5.4 --- Changes in cation nutrients after rehabilitation --- p.57 / Chapter 3.5.5 --- Comparison of ecosystem rehabilitation with other studies --- p.60 / Chapter 3.6 --- Conclusion --- p.66 / Chapter CHAPTER 4 --- NITROGEN MINERALIZATION / Chapter 4.1 --- Introduction --- p.68 / Chapter 4.2 --- Methodology --- p.73 / Chapter 4.2.1 --- In situ incubation --- p.73 / Chapter 4.2.2 --- "Determination of N mineralization, uptake and leaching" --- p.75 / Chapter 4.3 --- Statistical analysis --- p.76 / Chapter 4.4 --- Results --- p.76 / Chapter 4.4.1 --- Temporal variations of NH4-N and N03-N in the rehabilitated sites --- p.76 / Chapter 4.4.2 --- "Net ammonification, nitrification and N mineralization in the rehabilitated sites" --- p.78 / Chapter 4.4.3 --- Uptake of mineral N in the rehabilitated sites --- p.80 / Chapter 4.4.4 --- Leaching loss of mineral N in the rehabilitated sites --- p.82 / Chapter 4.5 --- Discussion --- p.84 / Chapter 4.5.1 --- Nitrogen mineralization in the rehabilitated sites --- p.84 / Chapter 4.5.2 --- Uptake of mineral nitrogen in the newly rehabilitated sites --- p.92 / Chapter 4.5.3 --- Leaching loss of and mechanisms to conserve mineral nitrogen in newly rehabilitated sites --- p.96 / Chapter 4.6 --- Conclusion --- p.98 / Chapter CHAPTER 5 --- SOIL RESPIRATION IN NEWLY REHABILITATED BORROW AREA / Chapter 5.1 --- Introduction --- p.100 / Chapter 5.2 --- Methodology --- p.105 / Chapter 5.3 --- Statistical analysis --- p.107 / Chapter 5.4 --- Results --- p.107 / Chapter 5.5 --- Discussion --- p.109 / Chapter 5.5.1 --- Inherent microbial activities of the newly excavated soil --- p.109 / Chapter 5.5.2 --- Effects of young plantations on soil respiration --- p.110 / Chapter 5.5.3 --- Comparison of soil respiration between the rehabilitated sites and secondary Pinus massoniana woodland --- p.114 / Chapter 5.6 --- Conclusion --- p.116 / Chapter CHAPTER 6 --- GROWTH PERFORMANCE AND FOLIAR COMPOSITION OF REHABILITATED VEGETATION / Chapter 6.1 --- Introduction --- p.118 / Chapter 6.2 --- Methodology --- p.122 / Chapter 6.2.1 --- Growth performance measurements --- p.122 / Chapter 6.2.2 --- Chemical analysis --- p.123 / Chapter 6.3 --- Statistical analysis --- p.124 / Chapter 6.4 --- Results --- p.124 / Chapter 6.4.1 --- Growth measurements --- p.124 / Chapter 6.4.1.1 --- Height --- p.124 / Chapter 6.4.1.2 --- Stem basal diameter (SBD) --- p.127 / Chapter 6.4.1.3 --- Crown coverage --- p.130 / Chapter 6.4.2 --- Foliar nutrient composition of rehabilitated vegetation --- p.133 / Chapter 6.4.2.1 --- Total Kjeldahl nitrogen --- p.133 / Chapter 6.4.2.2 --- Total phosphorus --- p.134 / Chapter 6.4.2.3 --- Potassium --- p.136 / Chapter 6.4.2.4 --- Sodium --- p.137 / Chapter 6.4.2.5 --- Calcium --- p.138 / Chapter 6.4.2.6 --- Magnesium --- p.140 / Chapter 6.4.3 --- Element abundance among the rehabilitated species --- p.142 / Chapter 6.5 --- Discussion --- p.142 / Chapter 6.5.1 --- Species growth in the rehabilitated sites --- p.142 / Chapter 6.5.2 --- Role of nitrogen fixers in rehabilitating the borrow area --- p.144 / Chapter 6.5.3 --- Species selection in ecosystem restoration --- p.150 / Chapter 6.6 --- Conclusion --- p.154 / Chapter CHAPTER 7 --- CONCLUSION / Chapter 7.1 --- Summary of findings --- p.156 / Chapter 7.2 --- Implications of the study --- p.161 / Chapter 7.2.1 --- Ecosystem restoration strategy in Hong Kong --- p.161 / Chapter 7.2.2 --- Can native species establish on degraded land? --- p.164 / Chapter 7.2.3 --- Are the present findings transferable to other areas? --- p.167 / Chapter 7.3 --- Limitations of the study --- p.169 / Chapter 7.4 --- Suggestion for future studies --- p.171 / REFERENCES --- p.173 / APPENDICES --- p.192
107

Modeling of Hydrodynamic Circulation and Cohesive Sediment Transport and Prediction of Shoreline Erosion in Hartwell Lake, SC/GA

Seker-Elci, Sebnem 12 July 2004 (has links)
This dissertation addresses hydrodynamics, sediment transport and shoreline erosion within the main pool of Hartwell Lake, a U.S. Army Corps of Engineers reservoir built on the Savannah River, between Anderson, South Carolina, and Hartwell, Georgia, USA. A U.S. Environmental Protection Agency (EPA) Superfund site is located on a tributary of Hartwell Lake because of high concentrations of polychlorinated biphenyls (PCBs) in the lake sediments. PCBs are hydrophobic and typically bond to fine-grained sediments, such as silts and clays. The primary goal of the study was to document, through field measurements, and model, using a 3-D numerical model of flow and sediment transport, the fate of sediments within the main pool of Hartwell Lake. To document forty years of sedimentation within the reservoir, bathymetric survey data were collected in Hartwell Lake during the period, February 10-14, 2003. The bathymetric surveys revealed that deposition was, in places, up to two meters thickness in forty years. During the field campaign, flow velocity measurements were made primarily to provide a check on the magnitude of the velocities predicted by the numerical model used in the study. Shoreline surveys provided data for the modeling procedure for shoreline change. This in turn facilitated specification of the sediment flux into the domain via shoreline erosion. Hartwell Lake is located near the southern terminus of the Appalachian mountain chain in the Piedmont region. Sediments contain high fractions of silt and clay. Hartwell Lake has a shoreline length of 1548 km, and erosion of lake shorelines has been a significant problem for many homeowners. As of September 2002, there were 1123 permitted riprap installations, and 393 permitted retaining walls, for a total of 1516 erosion control structures along the lakeshores (source: USACE Hartwell Office), an indication of the magnitude of the erosion problem. To quantify the erosion rate of the shorelines, an approach that relates erosion rates to wind wave forces was developed. A simplified representation of the shape of beach profiles is employed. Historical shoreline change rates were quantified by comparing available digital aerial photos taken in different years, and the erosion prediction model was calibrated using these computed erosion rates. Sediments derived from shoreline erosion were introduced to the model as an additional source along the model boundary, and the fate of the eroding sediments was investigated via numerical modeling.
108

Soil conservation as a model for managing change in rural landscapes

Venker, John Stephen. January 1984 (has links)
Call number: LD2668 .T4 1984 V465 / Master of Landscape Architecture
109

Use of bentonite to stabilize sandy soil material in a wind tunnel study

Diouf, Babou. January 1986 (has links)
Call number: LD2668 .T4 1986 D56 / Master of Science / Agronomy
110

Reciprocal relationships between vegetation structure and soil properties in selected biomes of South Africa

Mills, A. J. 12 1900 (has links)
Thesis (PhD) -- Stellenbosch University, 2003. / Please refer to full text to view abstract. / ENGLISH ABSTRACT: The effects of different land use practices on soil quality in South Africa were investigated in five contrasting biomes, with a particular emphasis on the tendency of soils to crust and soil C content. Soil quality is a nebulous concept and its applicability in the South African landscape is scrutinised. A wide range of chemical and physical soil properties were examined. The tendency of soils to crust was assessed using modulus of rupture, water dispersible clay and a new method of laboratory infiltration which was verified with rainfall simulation. Crusting was greater in bare, exposed soils than soils under vegetation and varied with soil parent material. Differences in crusting are explained by factors relating to clay dispersion such as clay mineralogy, soil C, labile or readily oxidisable C, concentration of soluble salts, soil texture and exchangeable Na percentage (ESP). Results from longterm bum plots in savanna and grassland revealed that annual burning can increase the tendency of soils to crust. Greater crusting in burnt plots is ascribed to greater dispersion of clay, which in tum is attributed to a decline in soil C, a decline in EC and an increase in ESP. The loss of nutrients from burnt plots over time is ascribed to removal of ash in surface runoff. Calcium, Mg, and K were lost more readily than Na probably because plants take up these nutrients in greater concentration than Na. The net effect was an increase in ESP. Crusting on burnt plots may be self-perpetuating, because increased runoff is likely to incsease the loss of soluble salts. Removal of vegetation due to cultivation, grazing or burning reduced soil C at all sites. Mean soil C in the 0-1 cm layer of unburnt plots in the Kruger National Park was more than three times greater than in burnt plots (2.7 vs 0.8%). The difference in soil C between treatments decreased with depth and illustrated that sampling to depths greater than a few centimetres can obscure effects of land use. The top few centimetres of soil have a disproportionate effect on soil infiltrability and nutrient cycling. This layer was named the pedoderm. Tree cover on burnt plots in the southern Kruger Nationa--l- Park is highly variable, and was hypothesised to be a function of herbivory pressure. Herbivores tended to congregate on plots with the greatest clay, Zn and Mn content and the lowest tree cover. It is suggested that soil properties determine the abundance of herbivores after fire, which in tum affects tree cover. In the Eastern Cape,intensive stocking with goats transforms dense thicket to an open savanna. Soils from goat-transformed sites had a greater tendency to crust than soils from intact thicket, probably due to aggregate weakening associated with a decline in soil C. Mean soil C content of intact thicket was almost double that of goat-transformed thicket (5.6 vs. 3% to a depth of 10 cm) and is exceptionally high for a semi-arid region. The potential to sequestrate carbon in degraded thicket landscapes is thus considerable. Managing the land for greater sequestration of C will have the added benefit of increasing soil aggregate stability, reducing the tendency of soils to crust and therefore increasing the rate of water infiltration through the pedoderm. The benefits of such an approach have been recognised by specialists in soil conservation and rural land use for many decades, based largely on empirical observation. The results of this thesis provide a more quantitative basis for appreciating the effects of soil C across a broad spectrum of South African biomes. / AFRIKAANSE OPSOMMING: Die invloed van verskillende landgebruikspraktyke op grondkwaliteit in Suid-Afrika is in vyf kontrasterende biome ondersoek met spesifieke klem op die neiging van gronde om korste te vorm en die grond koolstofinhoud. Grondkwaliteit is 'n vae konsep en die toepassing daarvan in die Suid-Afrikaanse grondlandskap is noukeurig ondersoek. 'n Wye reeks van chemiese en fisiese grondeienskappe is ondersoek. Die neiging van korsvorming by gronde is beraam deur die gebruik van breukmodulus, waterdispergeerbare klei en 'n nuwe metode van laboratorium-infiltrasie wat met behulp van reënvalsimulasie gekontroleer is. Korsvorming was groter in kaal, blootgestelde gronde as in gronde met 'n plantbedekking en het gewissel volgens moedermateriaal. Verskille in korsvorming word verklaar deur faktore wat verband hou met kleidispergering soos byvoorbeeld kleimineralogie, grondkoolstof, labiele of maklik oksideerbare koolstof, konsentrasie oplosbare soute, grondtekstuur en uitruilbare natriumpersentasie (UNP). Resultate van langtermyn brandpersele in savanna en grasland het getoon dat jaarlikse brand die neiging tot korsvorming kan verhoog. Meer korsvorming in brandpersele word toegeskryf aan groter kleidispergering, wat waarskynlik verband hou met 'n afname in grondkoolstof, 'n afname in elektriese geleiding (Be) en 'n toename in UNP. Plantvoedingstowwe gaan oor tyd verlore uit brandpersele, waarskynlik deur die verwydering van as in oppervlak afloop. Kalsium, Mg en K gaan meer geredelik verlore as Na, waarskynlik omdat plante hierdie voedingstowwe in groter hoeveelhede opneem as Na. Die netto effek is 'n toename in UNP. Korsvorming op brandpersele kan self instand gehou word omdat verhoogde afloop die moontlike verlies van oplosbare soute kan verhoog. Verwydering van plantegroei deur bewerking, beweiding of brand het grondkoolstof op alle plekke verlaag. Die gemiddelde grondkoolstof in die 0-1 cm laag van ongebrande persele in die Kruger Nasionale Park was meer as drie maal groter as in --.. brandpersele (2.7 vs 0.8 %). Die verskil in grondkoolstof tussen behandelings neem af met diepte wat daarop dui dat monsterneming tot dieptes groter as 'n paar sentimeters die effek van landgebruik kan verberg. Die boonste paar sentimeters van 'n grond het 'n oneweredige invloed op infiltrasie en voedingstofsirkulasie. Hierdie laag word die pedoderm genoem. Boombedekking op brandperseie in die suidelikeKruger Nasionale Park is hoogs variërend. Die hipotese was dat dit 'n funksie van druk deur planteters is. Planteters neig om op persele met die hoogste klei, Zn- en Mn-inhoud en die laagste boom bedekking te versamel. Daar word voorgestel dat grondeienskappe die hoeveelheid planteters na 'n brand bepaal. Dit beïnvloed op sy beurt weer die boombedekking. In die Oos-Kaap het intensiewe bokboerdery digte bosruigtes verander na oop savannas. Gronde van bok-veranderde lokaliteite het 'n groter neiging tot korsvorming as gronde van onveranderde bosruigtes, vermoedelik as gevolg van verswakking van aggregate met 'n. afname in grondkoolstof. Die gemiddelde grondkoolstof van onveranderde bosruigtes was byna dubbel soveel as die koolstof van bok-veranderde bosruigtes (5.6 vs 3 % tot 'n diepte van 10 cm) en buitengewoon hoog vir 'n semi-ariede streek. Die potensiaal vir koolstof sekwestrasie in degradeerde bosruigte landskappe is dus aansienlik. Bestuur van land vir groter sekwestrasie van koolstof het die bykomende voordeel van verhoogde grond aggregaatstabilteit, verlaging van die neiging tot korsvorming en daardeur 'n verhoging in die tempo van waterinfiltrasie deur die pedoderm. Die voordele van so 'n benadering is vir baie dekades deur spesialiste in grondbewaring en landelike landgebruik herken. Dit was grootliks gebaseer op empiriese waarneming. Die resultate van hierdie tesis bied 'n meer kwantitatiewe basis tot die verstaan van die invloed van grondkoolstof oor 'n breë spektrum van Suid-Afrikaanse biorne.

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