Application of Dust Mitigation Strategies to Single-Axis-Tracking Photovoltaic Modules in the Semi-Arid Areas of South Africa

Groundwater is the main water resource in arid and semi-arid areas. Its evaluation in terms of recharge, discharge, flow system and change in storage is thus vital for management purposes. However, distributed numerical models which are considered as favourable tools for assessment of groundwater resources are often limited by availability of input data especially in arid and semi-arid areas in developing countries where monitoring networks are scarce. Moreover, in case of transboundary aquifers, political, institutional, cultural, socio-economic differences among countries make management of groundwater even more complex.Remote sensing is a handy tool for monitoring water resources in data scarce areas. This study entails application of remote sensing data in developing a distributed integrated hydrological model for Stampriet Transboundary Aquifer System using MODFLOW-NWT coupled with the Unsaturated Zone Flow (UZF1) Package.Stampriet Transboundary Aquifer is a multi-layered aquifer system shared between Namibia, Botswana and South Africa. The aquifer system consists of three aquifers, characterized by low transmissivity and low storage, intercalated by two aquitards. Conceptually, the physical processes taking place in this system are reasonably understood in Namibia and not as much in Botswana and South Africa. However, quantification of water resources and fluxes is still limited.The aquifer system is mainly exploited in Namibia for socio-economic growth, where abstraction from storage has led to decline in local groundwater level. Water quality constraints have restrained its usage in South Africa, while in Botswana the potential for available resources is likely to be exploited, but there is not enough data for making firm decisions.A numerical model has been set &#8211; up in transient conditions at daily time step and calibrated with groundwater levels as the state variables and satellite rainfall and potential evapotranspiration as the model driving forces. The calibrated model provides spatio-temporal water flux dynamics as well as water balances and hence an understanding of the groundwater-resource dynamics and replenishment. The results are compared to analysis of GRACE data to further constrain the model. This information is useful for proper management of the transboundary water resource as well as for policy making.

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Influence of heat stress on milk production and its financial implications in semi-arid areas of South Africa

Heliyon ◽

10.1016/j.heliyon.2021.e06202 ◽

2021 ◽

Vol 7 (2) ◽

pp. e06202

Author(s):

Abiodun A. Ogundeji ◽

Hermela Lakew ◽

Weldemichael Tesfuhuney ◽

Willem Lombard

Keyword(s):

South Africa ◽

Heat Stress ◽

Milk Production ◽

Arid Areas ◽

Semi Arid

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Lantana camara: Poisonous Species and a Potential Browse Species for Goats in Southern Africa—A Review

Sustainability ◽

10.3390/su14020751 ◽

2022 ◽

Vol 14 (2) ◽

pp. 751

Author(s):

Malizo Ntalo ◽

Khuliso Emmanuel Ravhuhali ◽

Bethwell Moyo ◽

Onke Hawu ◽

Ntokozo Happy Msiza

Keyword(s):

Southern Africa ◽

Small Ruminants ◽

Lantana Camara ◽

Mitigation Strategies ◽

Control Measures ◽

Management Tool ◽

Arid Areas ◽

Browse Species ◽

Semi Arid ◽

Ruminant Livestock

Among the possible impacts of plant invaders on South African biodiversity, water supplies, and rangeland production, Lantana camara is ranked the highest in terms of its environmental impact. Globally, L. camara is regarded as one of the most ecologically and economically destructive invasive alien plants. The spread of L. camara affects the environment and threatens livestock productivity due to its toxicity to animals (especial cattle and sheep) in most semi-arid areas of South Africa. Lantana camara is known to have high concentrations of nutrients that are beneficial to livestock, but most previous research has concentrated on its toxicity. To enrich our knowledge on its nutritive value, further research has to evaluate its dietary impact on the growth and health of different ruminant livestock species, particularly goats. This review evaluates L. camara as a potential browse species for goats in southern Africa, and its adverse effects on goats and other ruminant livestock are also presented. The review describes L. camara and its distribution globally, its poisonous effect to livestock, and potential use as an alternative forage to browsing animals such as goats, which have proved resistant to its harmful traits. The high crude protein content, low fibre and adequate macro-minerals for small ruminants makes L. camara a good ruminant protein supplement in semi-arid areas. In addition to other biological control strategies, the prospects of using goats as a biological management tool is discussed. The research will contribute to the understanding of the control measures of L. camara while improving the productivity of small stock, especially goats. This means that a balanced understanding of its nutritional value as a source of protein and its negative impact on the environment should be considered in developing mitigation strategies to arrest its spread. We, therefore, recommend the use of goats in the control of L. camara; however, further studies are needed to limit its toxic effects, and thus improve its value.

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Prosopis Species—An Invasive Species and a Potential Source of Browse for Livestock in Semi-Arid Areas of South Africa

Sustainability ◽

10.3390/su13137369 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7369

Author(s):

Khuliso Emmanuel Ravhuhali ◽

Humbelani Silas Mudau ◽

Bethwell Moyo ◽

Onke Hawu ◽

Ntokozo Happy Msiza

Keyword(s):

South Africa ◽

Invasive Species ◽

Plant Species ◽

Nutritive Value ◽

Negative Impact ◽

Dry Season ◽

Environmental Harm ◽

Arid Areas ◽

Feed Source ◽

Semi Arid

Globally, there have been differing views on whether the proliferation of invasive species will be of benefit as a livestock feed source or it will have detrimental effects on the ecosystem. The infestation of invasive plants such as Prosopis species does not only affect the groundwater levels but also threatens the grazing capacity and species richness of most of the semi-arid areas around South Africa. Though Prosopis is invasive, it is however of good nutritive value and can serve as an alternative source of protein and minerals for livestock during the dry season. Bush encroachment by browsable invasive species can be controlled through biological methods by using organisms such as livestock. The utilisation of Prosopis through browse benefits livestock production and at the same time reduces its spread, thereby preventing possible environmental harm that may arise. Although several studies have been carried out globally on the assessment of the Prosopis species’ nutritive value and also on the threat of this invasive species to the environment, there is a need to update the state of knowledge on this species, particularly in the context of the semi-arid areas of South Africa where the dry season is characterised by less herbage of poor quality. It is therefore critical to understand whether Prosopis is a beneficial invader, or a detriment that needs to be eradicated. This review will contribute knowledge towards finding practical solutions to controlling Prosopis species and whether utilising Prosopis as a feed source will limit its spread and result in a vegetation structure where Prosopis becomes part of the ecosystem with limited detrimental impact. This means that the several components of the species such as nutritive value and the negative impact associated with this plant species along with the means to control its spreading must be well understood to recognise the plant species’ vital contribution to the ecosystem.

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Decision support for long-term water resource management in semi-arid areas: insights from South Africa

Environmental Economics and Investment Assessment ◽

10.2495/eeia060271 ◽

2006 ◽

Author(s):

W. J. de Lange ◽

T. E. Kleynhans

Keyword(s):

South Africa ◽

Decision Support ◽

Resource Management ◽

Water Resource ◽

Water Resource Management ◽

Arid Areas ◽

Semi Arid

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Variability of serum reproductive hormones in cows presenting various reproductive conditions in semi-arid areas of the North West Province, South Africa

Veterinary World ◽

10.14202/vetworld.2020.502-507 ◽

2020 ◽

Vol 13 (3) ◽

pp. 502-507

Author(s):

K. Molefe ◽

M. Mwanza

Keyword(s):

South Africa ◽

Vaginal Prolapse ◽

Arid Areas ◽

Blood Samples ◽

Hormonal Profile ◽

Retained Placenta ◽

North West ◽

The North ◽

Downer Cow Syndrome ◽

Semi Arid

Background and Aim: Hormones play a significant role in supporting reproductive processes. Predisposition to metabolic disorders may result from biological alterations in the neurohormonal system, thus leading to impaired immune function and poor reproductive performance. The aim of this study was to determine the reproductive hormonal profile in cows with reproductive conditions in semi-arid areas of the North West Province, South Africa, to establish possible correlations between different conditions and the hormonal profile. Materials and Methods: Blood samples were collected from cows in different communal areas of Mafikeng. Convenience sampling was used to collect samples for the study. Blood samples were collected cows experiencing dystocia (n=50), retained placenta (n=13), downer cow syndrome (n=34), vaginal prolapse (n=16), and abortions (n=69), following cases reported at the Animal Health Hospital of the North-West University, Mafikeng Campus. Descriptive statistics, such as mean and standard deviations, were used to describe the distribution of hormone levels across reproductive conditions. p-value less than the significance level was set at 5% (p<0.05). Results: Data obtained revealed significantly higher estradiol in abortion (1122.99±71.99 pg/ml), downer cow syndrome (781.32±135.7 pg/ml), and dystocia (862.09±123.44 pg/ml). Oxytocin (OT) differed significantly in cows with dystocia (370.50±71.66 pg/ml) and abortion (574.73±60.65 pg/ml). Significantly low progesterone (Pg) was observed in abortion (2.45±1.509 ng/ml) and dystocia (8.59±0.402 ng/ml) while increased prostaglandin alpha was observed in cows with vaginal prolapse and abortion. Conclusion: The findings highlight an increase in serum estradiol and OT in aborting cows. Low Pg and estradiol in cows with vaginal prolapses and retained placenta were noted. An association was seen between downer cow syndrome and high concentrations of estradiol and Pg. Prostaglandin alpha may increase in cases of vaginal prolapse and abortion. Hormonal alterations were observed and may contribute to the incidences of different reproductive conditions.

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