Weidingsbestuur is 'n filosofie. Jy kan resepte he, maar enige bestuur op 'n plaas is omgewingspesifiek. Dit beteken jy moet jou aksies aanpas binne 'n filosofiese raamwerk. As 'n mens na die situasie in die land kyk, is... more
Weidingsbestuur is 'n filosofie. Jy kan resepte he, maar enige bestuur op 'n plaas is omgewingspesifiek. Dit beteken jy moet jou aksies aanpas binne 'n filosofiese raamwerk. As 'n mens na die situasie in die land kyk, is dit moeilik om reels neer te le wat oral geld. Kom ons aanvaar dus dat elke boer op grond van sy eie situasie hierdie riglyne sal aanpas.
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Philosophy and Theology
Dodder (genus Cuscuta) dek om en by 100 tot 170 parasitiese spesies wereldwyd. Dit behoort aan die Convolvulaceae-plantfamilie. Dit kom oor die hele wereld voor en is by gematigde, subtropiese en tropiese toestande aangepas. Die grootste... more
Dodder (genus Cuscuta) dek om en by 100 tot 170 parasitiese spesies wereldwyd. Dit behoort aan die Convolvulaceae-plantfamilie. Dit kom oor die hele wereld voor en is by gematigde, subtropiese en tropiese toestande aangepas. Die grootste spesiediversiteit kom egter voor in subtropiese en tropiese klimaatstreke.
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Engineering and Cuscuta
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Ekonomiese veeproduksie, wat reeds gebuk gaan onder stygende insetkoste en wisselvallige beskikbaarheid van byvoedings en konsentrate, kan 'n groot hupstoot kry deur die optimale benutting van natuurlike en aangeplante weidings.
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Summaries in Afrikaans and English. Thesis (M. Sc.(Agric.))(Pasture Science)--University of Pretoria, 2002.
The combustion of coal in South Africa produces approximately 22 million tons of fly ash annually. This fly ash has to be handled and stored on ash dumps, which in turn have to be rehabilitated – increasing the cost of ash handling.... more
The combustion of coal in South Africa produces approximately 22 million tons of fly ash annually. This fly ash has to be handled and stored on ash dumps, which in turn have to be rehabilitated – increasing the cost of ash handling. Sewage sludge is classified as a hazardous, toxic waste. It requires expensive methods of treatment. This investigation was concerned with the co-utilisation of these otherwise waste products to form an odourless, pasteurised, soil-like product with only the beneficial characteristics of both components (high organic load and low levels of available heavy metals). The pasteurisation of the sewage sludge is achieved due to the exothermic reaction between the highly alkaline, lime amended, fly ash and the moisture of the sewage sludge. This process is sufficient to treat the sewage sludge to the USEPA PFRP (Process to Further Reduce Pathogens) levels. SLASH has been added to soil to determine whether the bound heavy metals, present in the product from the ...
Sustainable cultivated pasture production in the southern Cape region of South Africa requires management practices that will support soil quality (Swanepoel and Botha 2012). Soil organic carbon (Corg) sequestration is regarded as one of... more
Sustainable cultivated pasture production in the southern Cape region of South Africa requires management practices that will support soil quality (Swanepoel and Botha 2012). Soil organic carbon (Corg) sequestration is regarded as one of the most important ways to promote soil quality. Dairy farmers in the southern Cape attempt to increase Corg by following minimum-tillage practices. These irrigated dairy-pastures require high levels of nitrogen (N) to maintain highly productive pastures. Nitrogen fertilisers have be-come very expensive and severely strain profitability of these dairy-pastures. Forage legumes are frequently incorporated into the grass pastures to overcome economic and environmental problems associated with high levels of inorganic fertiliser application. Their capacity to fixate atmospheric N contributes greatly to nutritional value, palatability and subsequently profitability of pastures (Botha 2003). Since C and N are biophilic compounds, Corg may have a direct ef...
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Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The... more
Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The aim of the study was to quantify the pasture and milk production potential of kikuyu over-sown with Italian ryegrass (Lolium multiflorum var. italicum), Westerwolds ryegrass (L. multiflorum var. westerwoldicum) or perennial ryegrass (L. perenne). The study was conducted for 2 years on existing kikuyu pastures grazed by Jersey cows. Growth rate, dry matter (DM) production, botanical composition, forage quality, grazing capacity, milk composition and milk production were determined. Whilst each pasture type reached their peak growth rates during different months, the perennial ryegrass treatment maintained DM production during periods when the remaining pastures experienced a decrease in production. As a result, perennial ryegrass pasture maximised an...
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Overcoming Limitations of Ecology and Engineering in Addressing Society's Challenges By providing an integrated, systems-approach to problem-solving that incorporates ecological principles in engineering design, ecological engineering... more
Overcoming Limitations of Ecology and Engineering in Addressing Society's Challenges By providing an integrated, systems-approach to problem-solving that incorporates ecological principles in engineering design, ecological engineering addresses, many of the limitations of Ecology and Engineering needed to work out how people and nature can beneficially coexist on planet Earth. Despite its origins in the 1950s, ecological engineering remains a niche discipline, while at the same time, there has never been a greater need to combine the rigour of engineering and science with the systems-approach of ecology for pro-active management of Earth's biodiversity and environmental life-support systems. Broad consensus on the scope and defining elements of ecological engineering and development of a globally consistent ecological engineering curriculum are key pillars to mainstream recognition of the discipline and practice of ecological engineering. The Importance of Ecological Enginee...
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acidic, infertile and unstable soils with urban and industrial byproducts
In South Africa approximately 28 million tons of ash are produced annually. This is a largely untapped resource, which is widely used in the cement industry. The benefits of using ash in the cultivation of plants has been extensively... more
In South Africa approximately 28 million tons of ash are produced annually. This is a largely untapped resource, which is widely used in the cement industry. The benefits of using ash in the cultivation of plants has been extensively investigated (Olbrich, 1995) and research as to its use in
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Coal mining impacts large areas in the grasslands of the Mpumalanga Province of South Africa.To mitigate such impacts, it is imperative to restore the once productive soils to the best possible condition.The re‐vegetation of mined land... more
Coal mining impacts large areas in the grasslands of the Mpumalanga Province of South Africa.To mitigate such impacts, it is imperative to restore the once productive soils to the best possible condition.The re‐vegetation of mined land presents a particular challenge because cover soils are often acidic and nutrient deficient.It is current practice to amend such soils using lime and inorganic fertilizer.Research over the past 8‐10 years into the use of a coal combustion by‐product (CCB's)‐class F fly ash,and an organic material such as sewage sludge,has demonstrated the feasibility of using such materials to amend acidic and infertile substrates (Norton et al., 1998 ; Truter and Rethman,2002 ; Truter,2007).The objective of this research was to determine if alternative amendments could create a more sustainable system, in which botanical composition, basal cover, plant productivity and soil chemical properties were improved.
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Surface mining of coal is widespread in the grassland areas of the Mpumalanga Province in South Africa, and is the main cause of many environmental impacts in this agriculturally important region. To ensure healthy and productive... more
Surface mining of coal is widespread in the grassland areas of the Mpumalanga Province in South Africa, and is the main cause of many environmental impacts in this agriculturally important region. To ensure healthy and productive vegetation after the reclamation process, disturbed soils need to be ameliorated and re-vegetated with locally adapted grass species to protect, preserve and improve soils for future agricultural use. To date, soil compaction is regarded as one of the main factors that cause severe restrictions in the effective rooting depth of plants, and the level of compaction is strongly influenced by altered soil water contents, soil texture, soil structure and often non-existing organic matter contents. Imported organic materials and enhanced plant root development may lead to reduced effects of soil compaction and an increased amount of moisture in the soil profile, which becomes available for plant growth during the growing season. This research focussed on the vari...
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The combustion of coal in South Africa produces approximately 22 million tons of fly ash annually. This fly ash has to be handled and stored on ash dumps, which in turn have to be rehabilitated – increasing the cost of ash handling.... more
The combustion of coal in South Africa produces approximately 22 million tons of fly ash annually. This fly ash has to be handled and stored on ash dumps, which in turn have to be rehabilitated – increasing the cost of ash handling. Sewage sludge is classified as a hazardous, toxic waste. It requires expensive methods of treatment. This investigation was concerned with the co-utilisation of these otherwise waste products to form an odourless, pasteurised, soil-like product with only the beneficial characteristics of both components (high organic load and low levels of available heavy metals). The pasteurisation of the sewage sludge is achieved due to the exothermic reaction between the highly alkaline, lime amended, fly ash and the moisture of the sewage sludge. This process is sufficient to treat the sewage sludge to the USEPA PFRP (Process to Further Reduce Pathogens) levels. SLASH has been added to soil to determine whether the bound heavy metals, present in the product from the ...
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Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The... more
Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The aim of the study was to quantify the pasture and milk production potential of kikuyu over-sown with Italian ryegrass (Lolium multiflorum var. italicum), Westerwolds ryegrass (L. multiflorum var. westerwoldicum) or perennial ryegrass (L. perenne). The study was conducted for 2 years on existing kikuyu pastures grazed by Jersey cows. Growth rate, dry matter (DM) production, botanical composition, forage quality, grazing capacity, milk composition and milk production were determined. Whilst each pasture type reached their peak growth rates during different months, the perennial ryegrass treatment maintained DM production during periods when the remaining pastures experienced a decrease in production. As a result, perennial ryegrass pasture maximised an...
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Prime agricultural land is a limited resource in South Africa. It is, therefore, necessary to reclaim poor and disturbed soils to feed the burgeoning population. Using conventional methods is costly and not necessarily sustainable. The... more
Prime agricultural land is a limited resource in South Africa. It is, therefore, necessary to reclaim poor and disturbed soils to feed the burgeoning population. Using conventional methods is costly and not necessarily sustainable. The challenge is, therefore, to use potential alternative ameliorants in an economically, ecologically and socially sustainable manner. Previous research has shown that by mixing sewage sludge with class F fly ash and a suitable source of quicklime, the sewage sludge can be pasteurized. The SLudgeASH (SLASH) mixture has been extensively evaluated as a soil ameliorant and has proven to be viable for the reclamation of poor and marginal soils. Many pot and raised bed studies, focusing on the effect of SLASH on plant production of various plant species, have been conducted and reported on previously. This paper reports on subsequent research conducted to determine the effect of both fly ash and SLASH on the production of maize (Zea mays), wheat (Triticum aes...
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Prime agricultural land is a limited resource in South Africa. It is, therefore, necessary to reclaim poor and disturbed soils to feed the burgeoning population. Using conventional methods is costly and not necessarily sustainable. The... more
Prime agricultural land is a limited resource in South Africa. It is, therefore, necessary to reclaim poor and disturbed soils to feed the burgeoning population. Using conventional methods is costly and not necessarily sustainable. The challenge is to use alternative materials in an economically, ecologically and socially acceptable manner. Previous research has shown that sewage sludge can be pasteurized by mixing it with class F fly ash and a suitable source of quicklime. The SLudgeASH (SLASH) mixture has been extensively evaluated as a soil ameliorant and has proven to be viable for the reclamation of poor and marginal soils. Many studies previously conducted and reported on, have focused on the effect of class F fly ash and SLASH on soil chemical properties and consequently plant production of various plant species. This paper reports on subsequent research conducted to determine the effect of both class F fly ash and SLASH on soil physical and microbiological properties. SLASH ...
Lantana camara oftewel lantana, is een van die skadelikste uitheemse indringerplante. Dit kom in groot dele van die tropiese, subtropiese en warm, gematigde gebiede van die wereld voor. Lantana is 'n struik, maar die lote groei soms... more
Lantana camara oftewel lantana, is een van die skadelikste uitheemse indringerplante. Dit kom in groot dele van die tropiese, subtropiese en warm, gematigde gebiede van die wereld voor. Lantana is 'n struik, maar die lote groei soms binne-in aangrensende plante wat dit na 'n klimplantgroeiwyse kan laat lyk. Dit vorm digte stande wat die groei van ander plantsoorte en beweging vir mens en dier onmoontlik kan maak.
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The agricultural potential of surface coal mined soils is difficult to reclaim. It is possible to re-vegetate the covering topsoil, but the sustainability of many reclamation procedures is poor. This covering topsoil is exposed to... more
The agricultural potential of surface coal mined soils is difficult to reclaim. It is possible to re-vegetate the covering topsoil, but the sustainability of many reclamation procedures is poor. This covering topsoil is exposed to chemical and physical degradation over time lowering the agricultural potential of these newly created “productive lands”. This is due to the unsustainable fertilizer practices used during re-vegetation, the management of these production systems and the additional acidity generated in the soils/substrates by contaminants of pyritic material or the shallow underlying pyritic spoil material. Roots are unable to grow properly in these substrates and vegetation is unable to become productive in these hostile growth mediums due to the changed chemical and physical properties. As a result, the covering topsoil becomes unstable, and susceptible to erosion. The experimental work is to identify amelioration strategies for the cover soil using the coal combustion b...
The South African mining industry has been the backbone of the country’s economy for much of the past century. Mining has, however, often caused the degradation of productive soils. The amendment of these soils is often very expensive and... more
The South African mining industry has been the backbone of the country’s economy for much of the past century. Mining has, however, often caused the degradation of productive soils. The amendment of these soils is often very expensive and often not sustainable. The University of Pretoria in co-operation with Eskom TSI, has over the past ten years conducted a series of trials to determine the feasibility of using alkaline class F fly ash (from the coalbased Lethabo power generating facility) and organic materials to ameliorate acidic and infertile soils and substrates. In this investigation pot trials were conducted to measure and monitor the effect of different ameliorants on dry matter production and on the chemical properties of soils and substrates. Based on the results obtained in these pot trials, it was concluded that fly ash and fly ash/organic material mixtures improved dry matter production as well as the soil pH, ammonium acetate extractable K, Ca and Mg and Bray 1 extract...
Soil compaction impedes plant growth by negatively affecting water infiltration, soil aeration, access to soil water and nutrients, and consequently restricts root development. Previous studies to alleviate such problems in rehabilitated... more
Soil compaction impedes plant growth by negatively affecting water infiltration, soil aeration, access to soil water and nutrients, and consequently restricts root development. Previous studies to alleviate such problems in rehabilitated mine soils using a single amendment material did not provide a long lasting solution. The aim of the study was to quantify the role of different amendments in alleviating selected soil hydraulic properties. Five single amendment materials and three different blends of amendments were mixed thoroughly with degraded mine soil in a 1:3 (amendment:soil) ratio and packed in columns. Two additional unamended soils with different bulk densities were included as benchmarks. In general, the application of amendments reduced bulk density (BD) by 4–20%, enhanced infiltration rate by 15–70%, increased porosity by 5–35% and increased plant available water (PAW) by 9–33% compared with the unamended soils. Between amendments, the blends of amendments reduced BD by...
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Engineering and Imperata
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Ekonomiese veeproduksie, wat reeds gebuk gaan onder stygende insetkoste en wisselvallige beskikbaarheid van byvoedings en konsentrate, kan 'n groot hupstoot kry deur die optimale benutting van natuurlike en aangeplante weidings.
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Coal discard material is a difficult medium to prepare for successful re-vegetation. It is possible to re-vegetate the covering topsoil, but the sustainability of conventional procedures is often poor. This covering topsoil is acidified,... more
Coal discard material is a difficult medium to prepare for successful re-vegetation. It is possible to re-vegetate the covering topsoil, but the sustainability of conventional procedures is often poor. This covering topsoil is acidified, over time, by the capillary ...
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Applying cattle manure to soil in optimum rates can enhance soil fertility and plant growth. The objectives of this study were to investigate the influence of different rates of cattle manure application on soil fertility and the growth... more
Applying cattle manure to soil in optimum rates can enhance soil fertility and plant growth. The objectives of this study were to investigate the influence of different rates of cattle manure application on soil fertility and the growth and productivity of Tall Fescue (Festuca arundinaceae) and Smuts Finger grass (Digitaria eriantha), two popular pasture species in South Africa. These field trials were established on a uniform sandy clay loam (Hutton) soil on the Hatfield Experimental Farm, of the University of Pretoria in Pretoria. There were five treatments comprising five rates of cattle manure incorporation (0, 20, 40, 80 and 120 tonnes/ha). During the growing season, Tall Fescue plants from cattle manure-amended plots were significantly taller in the 80 tonnes/ha treatment, while Smuts Finger grass reached the maximum height in the 40 tonnes/ha treatment. The cattle manure-treated plots also produced greater leaf areas than the untreated control of both grasses. Dry matter yiel...
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The South African mining industry has been the backbone of the country's economy for much of the past century. Mining has, however, often caused the degradation of productive soils. The amendment of these soils is often very expensive... more
The South African mining industry has been the backbone of the country's economy for much of the past century. Mining has, however, often caused the degradation of productive soils. The amendment of these soils is often very expensive and often not sustainable. The University of Pretoria in co- operation with Eskom TSI, has over the past seven years conducted a series of trials. These trials have demonstrated the feasibility of using alkaline class F fly ash (from the coal-based Lethabo power generating facility) and organic materials to ameliorate acidic and infertile soils. Various pot and on-site field trials were established to measure and monitor the dry matter production, basal cover, botanical composition and the effect of amendments on the soil chemical properties. Based on the results obtained in the pot trials, it was concluded that fly ash and fly ash/organic material mixtures improved dry matter production as well as the soil pH, extractable K, Ca, Mg and P levels. T...
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Nitrogen and soil carbon restoration are crucial to maintain vegetation and increase species diversity on degraded mine areas. A significant proportion of mined areas in South Africa are not rehabilitated which weakens ecosystem... more
Nitrogen and soil carbon restoration are crucial to maintain vegetation and increase species diversity on degraded mine areas. A significant proportion of mined areas in South Africa are not rehabilitated which weakens ecosystem resilience. Significant progress on mine soil rehabilitation with grass pastures and terraces has been made. Indigenous herbaceous legumes have the additional benefit of fixing atmospheric nitrogen and restoring soil carbon. However, degraded mine soils reach high temperatures, potentially inhibiting seed germination, though this is poorly understood. The aim of this experiment was to assess the effects of soil temperature on the germination of indigenous legume species selected for mine soil rehabilitation. Seeds of four species growing in the Highveld and high rainfall area were selected, namely Tephrosia cordata, Tephrosia elongata, Rynchosia adenoides and the commercial legume, Medicago sativa . For each species 250 seeds were sown onto moistened filter ...
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Accurate feed budgeting and management of forage in grazing systems requires frequent assessment of forage mass and growth of pastures (Gabriёls and Van den Berg 1993; Sanderson et al. 2001). The rising plate meter (RPM) developed by... more
Accurate feed budgeting and management of forage in grazing systems requires frequent assessment of forage mass and growth of pastures (Gabriёls and Van den Berg 1993; Sanderson et al. 2001). The rising plate meter (RPM) developed by Earle and McGowan (1979) has been used widely by researchers and farmers to estimate pasture dry matter (DM) production. The advantages associated with using the RPM for the estimation of pasture DM yield include its low sensitivity to environmental conditions, stability of calibration equations across years and seasons (if pasture composition remains similar), and the fact that its robustness and ease of use makes it operator friendly, allowing a large number of readings to be taken in a short period of time (Earle and McGowan 1979; Michell 1982; Fulkerson and Slack 1993, Douglas and Crawford 1994, Martin et al. 2005). There is limited data available for the calibration of the RPM for kikuyu (Pennisetum clandestinum) pastures over-sown with ryegrass (L...
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Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/22/2-11/14 The 22nd International Grassland Congress (Revitalising Grasslands to Sustain Our Communities) took... more
Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/22/2-11/14 The 22nd International Grassland Congress (Revitalising Grasslands to Sustain Our Communities) took place in Sydney, Australia from September 15 through September 19, 2013. Proceedings Editors: David L. Michalk, Geoffrey D. Millar, Warwick B. Badgery, and Kim M. Broadfoot Publisher: New South Wales Department of Primary Industry, Kite St., Orange New South Wales, Australia