RECONSTRUCTING RECENT LAND DEGRADATION IN THE SEMI-ARID KAROO OF SOUTH AFRICA: A PALAEOECOLOGICAL STUDY AT COMPASSBERG, EASTERN CAPE

2012 ◽  
Vol 23 (6) ◽  
pp. 523-533 ◽  
Author(s):  
T. M. Mighall ◽  
I. D. L. Foster ◽  
K. M. Rowntree ◽  
J. Boardman
2020 ◽  
Vol 13 (22) ◽  
Author(s):  
Solomon Temidayo Owolabi ◽  
Kakaba Madi ◽  
Ahmed Mulakazi Kalumba ◽  
Israel Ropo Orimoloye

AbstractTheme unsuitability is noted to have inhibited the accuracy of groundwater potential zones (GWPZs) mapping approach, especially in a semi-arid environment where surface water supply is inadequate. This work, therefore presents a geoscience approach for mapping high-precision GWPZs peculiar to the semi-arid area, using Buffalo catchment, Eastern Cape, South Africa, as a case study. Maps of surficial-lithology, lineament-density, drainage-density, rainfall-distribution, normalized-difference-vegetation-index, topographic-wetness-index, land use/land cover, and land-surface-temperature were produced. These were overlaid based on analytical hierarchical process weightage prioritization at a constituency ratio of 0.087. The model categorizes GWPZs into the good (187 km2), moderate (338 km2), fair (406 km2), poor (185 km2), and very poor (121 km2) zones. The model validation using borehole yield through on the coefficient of determination (R2 = 0.901) and correlation (R = 0.949) indicates a significant replication of ground situation (p value < 0.001). The analysis corroboration shows that the groundwater is mainly hosted by a fractured aquifer where the GWPZs is either good (9.3 l/s) or moderate (5.5 l/s). The overall result indicates that the model approach is reliable and can be adopted for a reliable characterization of GWPZs in any semi-arid/arid environment.


Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 576
Author(s):  
Sixolise Mcinga ◽  
Lindah Muzangwa ◽  
Kudzayi Janhi ◽  
Pearson Nyari Stephano Mnkeni

Earthworms play a pivotal role in the regulation of soil health. Studies that explore the effects of conservation agriculture (CA) principles on earthworms under the semi-arid climate of the central Eastern Cape (EC) of South Africa (SA) are limited. Therefore, this study investigated the effects of tillage, crop rotations, and residue management on earthworms’ abundance and species richness. The study design followed a split-split plot with three replicates. The main plot was allocated to tillage treatment, which had conventional tillage (CT) and no-tillage (no-till) as factors. Crop rotation treatment was allocated to a subplot, and had maize (Zea mays)–fallow–maize (MFM), maize–fallow–soybean (Glycine max) (MFS), maize–wheat (Triticum aestivum)–maize (MWM), and maize–wheat–soybean (MWS). Residue management was in the sub-subplot with residue retention and residue removal. The study was carried out over four cropping seasons: summer 2015–2016, winter 2016, spring 2016, and summer 2016–2017. The results showed that the genera Amynthas and Lumbricus, both belonging to the anecic group, and Dendrobaena, belonging to the epigeic group, were present. Earthworm species diversity and density were highest under no-till than under CT. Residue retention improved earthworm density regardless of tillage management. Rotations that had fallow periods recorded lower earthworm numbers as compared to continuous cropping systems where wheat was grown in winter. The study concluded that maize–wheat–soybean (MWS) rotation with residue retention results in the highest earthworm abundance and species richness.


2021 ◽  
Author(s):  
Jussi Baade ◽  
Christiane Schmullius ◽  
Marcel Urban ◽  
Harald Kunstmann ◽  
Patrick Laux ◽  
...  

&lt;p&gt;For many decades the problem of land degradation has been an issue in South Africa. This is mainly due to the high variability of the mostly semi-arid climatic conditions providing a challenging environmental setting. Strong population growth and resulting socio-economic pressure on land resources aggravate the situation. Thus, reaching a number of Sustainable Development Goals (SDGs), like achieving food security (#2), access to clean water (#6), and the sustainable use of terrestrial (#15) and marine (#14) resources represents a challenge.&lt;/p&gt;&lt;p&gt;In South Africa, land degradation has been linked to the terms veld degradation and soil degradation and has been addressed by numerous measures over the past decades. However, there is still uncertainty on the extent of human induced land degradation as compared to periodic climate induced land surface property changes. In cooperation with South African institutions and stakeholders the overarching goal of SALDi is to implement novel, adaptive, and sustainable tools for assessing land degradation in multi-use landscapes. Building upon the state of the art in land degradation assessments, the project aims to advance current methodologies by innovatively incorporating inter-annual and seasonal variability in a spatially explicit approach. SALDi takes advantage of the emerging availability of high spatio-temporal resolution Earth observation data (e.g. Copernicus Sentinels, DLR TanDEM-X, NASA/USGS Landsat), growing sources of in-situ data and advancements in modelling approaches.&lt;/p&gt;&lt;p&gt;SALDi focusses on six study sites representing a major climate gradient from the (humid) winter-rainfall region in the SW across the (semi-arid) year-round rainfall to the (very humid) summer-rainfall region in the NE. The sites cover also different geological conditions and different agricultural practices. These include commercial, rain-fed and irrigated cropland, free-range cattle and sheep farming as well as communal and subsistence farming. Protected areas within our study regions represent benchmark sites, providing a foundation for baseline trend scenarios, against which climate-driven ecosystem-service dynamics of multi-used landscapes (cropland, rangeland, forests) will be evaluated.&lt;/p&gt;&lt;p&gt;The aim of this presentation is to provide an overview of recent activities and advancements in the three thematic fields addressed by the project:&lt;/p&gt;&lt;p&gt;i) to develop an automated system for high temporal frequency (bi-weekly) and spatial resolution (10 to 30 m) change detection monitoring of ecosystem service dynamics,&lt;/p&gt;&lt;p&gt;ii) to develop, adapt and apply a Regional Earth System Model (RESM) to South Africa and investigate the feedbacks between land surface properties and the regional climate,&lt;/p&gt;&lt;p&gt;iii) to advance current soil degradation process assessment tools for soil erosion.&lt;/p&gt;&lt;p&gt;A number of additional SALDi team member presentations will provide detailed information on current developments.&lt;/p&gt;


Author(s):  
Andries Jordaan ◽  
Yonas T. Bahta ◽  
Boitumelo Phatudi-Mphahlele

Estimation of ecological drought vulnerability indicators is the important step for drought mitigation management. This article identified and estimated ecological drought vulnerability indicators among communal farmers in the Eastern Cape province of South Africa, using an ecological vulnerability index based on a household survey of 121 communal farmers. The results identified overgrazing, soil erosion, land degradation, surface and groundwater supply, and land use management as the main ecological vulnerability variables. The results showed that climate is not necessarily linked to ecological vulnerability. High rainfall districts in this study showed higher ecological vulnerability to drought because of poor planning and management of water supply, poor grazing practices and land management that leads to serious land degradation. The identification and analysis of ecological vulnerability indicators to drought would aid in reconsidering priorities for the government to implement appropriate policy measures in response to drought and suggest strategies to reduce drought vulnerability. Such policies and strategies will strengthen climate change adaptation and ensure ecological and climate sustainability that comply with the Millennium Development Goals set out by the United Nations in 2000 and the subsequent 2030 development agenda for the Sustainable Development Goals.


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