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Organization of subject matter and development of an outline for teaching a course in soil and water conservationBlessing, Melvin E. January 1939 (has links)
Since this broad subject is now neither organized nor outlined, there is a particular need for a definite outline of material for teaching this course at Virginia Polytechnic Institute. The proposed outline, by eliminating overlapping subject matter, and by making use of the great abundance of experimental data and written material, will make it possible to give students a broad understanding of the fundamentals of the course in the short time allotted. This arrangement will also eliminate the necessity for students to purchase text books covering all the divisions, which is undesirable from an economic standpoint even if satisfactory texts were available. For the above reasons there is an urgent need to have in the department an up-to-date outline for the use of any instructor teaching the course.
The purpose of this outline is to enable the Agricultural Engineering Department to offer an improved course in soil and water conservation. In order to promote more efficient teaching, it seems desirable to combine the subjects of Soil Erosion, Drainage, Flood Control, and Irrigation in one course. The flexible nature of the outline method of presentation permits the inclusion of up-to-date material and will facilitate future revision.
The organization and development of material is, therefore, taken up as a thesis subject in the hope that a real contribution may be made to the work of the department, as well as to any instructor desiring to install a course of this kind. / Master of Science
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Effectiveness of cover crops in preventing soil erosionShulkcum, Edward January 1930 (has links)
M.S.
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Teaching resource use education in an elementary school through the planning of a resource unit in soil conservationJackson, Charles G. Unknown Date (has links)
No description available.
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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
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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 AnalysisKuiper, 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.
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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
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Modeling of Hydrodynamic Circulation and Cohesive Sediment Transport and Prediction of Shoreline Erosion in Hartwell Lake, SC/GASeker-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.
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Soil conservation as a model for managing change in rural landscapesVenker, John Stephen. January 1984 (has links)
Call number: LD2668 .T4 1984 V465 / Master of Landscape Architecture
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Use of bentonite to stabilize sandy soil material in a wind tunnel studyDiouf, Babou. January 1986 (has links)
Call number: LD2668 .T4 1986 D56 / Master of Science / Agronomy
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Reciprocal relationships between vegetation structure and soil properties in selected biomes of South AfricaMills, 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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