Spelling suggestions: "subject:"soil egradation"" "subject:"soil adegradation""
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The evaluation of the state of grass species composition in some degraded tribal areas in the Zeerust district / Ntombi Elizabeth MkhosiMkhosi, Ntombi Elizabeth January 2003 (has links)
The evaluation of the state of grass species composition was conducted as an attempt to
confirm the survey conducted by the United Nations Convention to Combat
Desertification (UNCCD), where the Zeerust District was identified as an area with
serious degradation problems. Quantitative data was obtained through botanical surveys
(April 2001-February 2002) and verified by household surveys (March 2001-April 2002).
Study sites included Braklaagte, Dinokana, Doomlaagte, Serake and Supingstad, with
benchmark sites in Madikwe Grune Reserve. Between 6-12 survey points per site were
selected after consultation with local Agricultural Extension Officers and communities.
Survey points included the range of veld condition between bush encroached and severely
denuded and eroded areas. The results indicate 12.3 % to 45.1 % loss of vegetal cover.
Resistance above 2 000 ohms, base saturation exceeding 100 % and pH values below 5.5
are evidence of soil degradation. The general profile of the fanning household is that of an aging adult community, with however, a relatively good knowledge of fanning practices. 52 % of the respondents depend on the government pension fund as a source of income. 60 % of the respondents use crop fanning products strictly for household purposes. Poor economic return from fanning activities has resulted in overutilization of the herbaceous layer with consequent changes of grass species composition towards retrogression and the establishment of woody species. This environmental degradation is a serious risk to long-term sustainable development. It is therefore, recommended that environmental education programmes and ecological restoration projects be started in degraded areas. The government should set up and enforce land-use policies. Community participation should be encouraged in all land care activities. Land degradation is a real social problem that must be tackled before many people's aspirations of a better life are met. / Thesis (M.Sc. (Biology) North-West University, Mafikeng Campus, 2003
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Effect of longwall mine subsidence on plant production on cropping landHinchliffe, D. Unknown Date (has links)
No description available.
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Determinants of farm level soil conservation technology adoption : lessons from the high rainfall, high populated, steep sloped Mt. Kenya highlands, Embu, Kenya /Kagwanja, Joan Cuka, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 128-134). Also available on the Internet.
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Determinants of farm level soil conservation technology adoption lessons from the high rainfall, high populated, steep sloped Mt. Kenya highlands, Embu, Kenya /Kagwanja, Joan Cuka, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 128-134). Also available on the Internet.
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Identification of the principal mechanisms driving soil organic carbon erosion across different spatial scales.Müller-Nedebock, Daniel January 2013 (has links)
Soil water erosion is recognized as the principal mechanisms behind soil organic carbon
(SOC) losses from soils, a soil constituent essential for ecosystem functions. SOC erosion can
thus be far-reaching, affecting the future human welfare and the sustainability of ecosystems.
Little research has yet been done to investigate the main mechanisms involved in the lateral
translocation of SOC on the landscape. Understanding the effects of the different water
erosion mechanisms, which control SOC losses (SOCL) at the hillslope level, creates scope
for further scientific studies.
Empirical data from 357 plots, with a range in slope length from 1 (n=117) to 22.1m (n=240)
were analysed to estimate the global variations of particulate organic carbon content (POCC),
POC losses (POCL) and sediment POC enrichment ratio (ER). The global average POCL rate
was calculated to be 12.1 g C m-2 y-1. Tropical clayey soil environments revealed the highest
POCL (POCL=18.0 g C m-2 y-1), followed by semi-arid sandy (POCL=16.2 g C m-2 y-1) and
temperate clayey soil environments (POCL=2.9 g C m-2 y-1). The global net amount of SOC
displaced from its original bulk soil on an annual basis was calculated to be 0.59±0.09 Gt C,
making up an approximated 6.5% of the net annual fossil fuel induced C emissions (9 Gt C).
POCL data for different spatial scales revealed that up to 83% of the eroded POC re-deposits
near its origin in hillslopes, and is not exported out of the catchment. The low organic carbon
sediment ER obtained from the data of clayey soils (ER of 1.1) suggests that most of the
eroded POC remains protected within soil aggregates. Consequently, erosion-induced carbon
dioxide (CO2) emissions in tropical areas with clayey soils are likely to be limited (less than
10%), as the process of POC re-burial in hillslopes is likely to decrease the rate of organic
matter (OM) decomposition and thus serve as a potential carbon sink. Water erosion in sandy
and silty soils revealed organic carbon sediment ER as high as 3.0 and 5.0, suggesting that in
these soils the eroded POC is not re-buried, but is made vulnerable to micro-decomposers,
thus adding to the atmospheric CO2 influx. The results obtained in the review study only
reaffirm that large variations of POCL are evident across the different pedo-climatic regions
of the world, making it a scientific imperative to conduct further studies investigating the link
between SOC erosion by water and the global carbon cycle.
A field study was designed to quantify the POC exported in the eroded sediments from
1x1m2 and 2x5m2 erosion plots, installed at different hillslope aspects, and to further identify
the main erosion mechanisms involved in SOC erosion and the pertaining factors of control.
The erosion plots were installed on five topographic positions under different soil types,
varying vegetation cover, and geology in the foothills of the Drakensberg mountain range of
South Africa. Soil loss (SL), sediment concentration (SC), runoff water (R) and POCL data
were obtained for every rainfall event from November 2010 up to February 2013. Scale ratios
were calculated to determine which erosion mechanism, rain-impacted flow versus raindrop
erosion, dominates R, SL and POCL. Averaged out across the 32 rainfall events, there were
no significant differences in R and POCL between the two plot sizes but SL were markedly
higher on the 5m compared to the 1m erosion plots (174.5 vs 27g m-1). This demonstrates that
the sheet erosion mechanism has a greater efficiency on longer as opposed to shorter slopes.
Rain-impacted flow was least effective where soils displayed high vegetation coverage (P <
0.05) and most efficient on steep slopes with a high prevalence of soil surface crusting. By
investigating the role of scale in erosion, it was possible to single out the controlling in situ
(soil surface related conditions) and ex situ (rainfall characteristics) involved in the export of
SOC from soils. This information will in future contribute toward generating SOC specific
models and thus further inform erosion mitigation. / M. Sc. University of KwaZulu-Natal, Durban 2013.
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Economics of soil compaction due to machinery traffic in QuebecLavoie, Gilbert January 1988 (has links)
No description available.
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Predicting hillslope scale erodibility and erosion on disturbed landscapes from laboratory scale measurementsSheridan, Gary James Unknown Date (has links)
No description available.
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Effect of longwall mine subsidence on plant production on cropping landHinchliffe, D. Unknown Date (has links)
No description available.
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Energy efficiency of tillage operations in CambodiaOm, S. Unknown Date (has links)
No description available.
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Effect of Tillage and Traffic on Soil OrganismsPangnakorn, U. Unknown Date (has links)
No description available.
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