Transvaal Highveld Research Articles

Soul-brother Eugène N. Marais: Some notes towards a re-edit of his works

The intention is to survey the current condition of the works of the South African Eugène Marais (1871–1936). This is with a view to alerting the general reader to certain inherited disorganisations which, in the light of professional scholarly and editing standards, need to be recognised and rectified. Marais’s output as a poet and short story writer, as well as the pioneer populariser of nature studies conducted particularly in the Transvaal Highveld after the Second Anglo-Boer War, in both official languages of his day (English and Afrikaans), have ensured him the status of a unique cultural icon. Yet the publishing opportunities open to him in his hand to mouth, haunted career, especially as a journalist, meant his contributions were assembled into book form haphazardly, or remained unrecuperated from often neglected periodicals of the mid-1890s to the mid1930s to which he contributed.

Regional atmospheric aerosol composition and sources in the eastern Transvaal, South Africa, and impact of biomass burning

As part of the Southern Africa Fire‐Atmosphere Research Initiative (SAFARI‐92), size‐fractionated aerosol samples were collected during September–October 1992 at three fixed ground‐based sites in the eastern Transvaal, i.e., at two sites within the Kruger National Park (KNP) and at a third site on the Transvaal highveld (about 150 km WSW of the KNP sites), and near a number of prescribed fires in the KNP. The collection devices consisted of stacked filter units, which separate the aerosol into a coarse (2–10 μm equivalent aerodynamic diameter (EAD)) and a fine (<2 μm EAD) size fraction, and of eight‐stage cascade impactors, which provide more detailed size fractionation. The samples were analyzed for particulate mass (PM), black carbon (BC), and up to 47 elements. The prescribed fires gave rise to high levels of airborne soil dust, but several species (elements) were particularly enriched in the pyrogenic emissions. This was the case for BC, P, K, Ca, Mn, Zn, Sr, and I in the coarse fraction, and for BC, the halogens (Cl, Br, I), K, Cu, Zn, Rb, Sb, Cs, and Pb (and in the flaming phase also Na and S) in the fine fraction. The aerosol concentrations, compositions, and time trends at the two KNP sites were quite similar, suggesting that regionally representative samples were collected. Receptor modeling calculations, using both absolute principal component analysis and chemical mass balance, indicated that the KNP coarse PM was essentially attributable to mineral dust and sea salt, with average relative apportionments of 75% and 25%, respectively. At the highveld site, mineral dust and sea salt contributed in a 99‐to‐1 ratio to the coarse PM. In the fine size fraction at all three fixed sites, four components were identified, i.e., mineral dust, sea salt, biomass burning products, and sulfate. The pyrogenic component was the dominant contributor to the atmospheric concentrations of BC, K, Zn, and I, a major source for PM, Cl, Cu, Br, and Cs, but only a minor source for S. About 40% of the fine PM was, on the average, attributed to the pyrogenic particles, and about one third of it to the sulfate component. Relation of the time trends of the various components with three‐dimensional air mass back trajectories indicated that elevated levels of pyrogenic products were mostly found in air masses arriving from the north. The levels of the sulfate component tended to be higher at the highveld site than at the two KNP sites, and this component was generally associated with continental air. It was concluded that the major contribution to this fine sulfate came from fossil fuel burning and various industrial activities on the Transvaal highveld.

Species turnover between Afromontane and eastern African lowland faunas: patterns shown by amphibians

Abstract. Following the recognition of a discrete East African lowland amphibian fauna (Poynton, 1990), this paper investigates the possible recognition of an Afromontane amphibian fauna in southern Africa. Species turnover in a transect from the Mozambique/KwaZulu‐Natal border area through Swaziland to the Eastern Transvaal highveld is described, and compared with previously described transects through Mozambique to Zimbabwe, and KwaZulu‐Natal to the central Free State. Turnover in the Swaziland transect shows two peaks. Marked turnover at the edge of the interior plateau is taken to indicate an eastern border of an Afromontane fauna; the other peak, at the western edge of the coastal lowland, is taken to mark the border of an East African lowland fauna. A transition zone with a transitional assemblage occurs on the plateau slopes between the two borders. The Zimbabwean transect shows a similar pattern. The KwaZulu‐Natal to Free State transect shows a broad transition from upland to lowland assemblages, which parallels the extensive intermingling of upland and lowland floristic elements in that area. A north‐south turnover across the three transects shows northern species becoming progressively excluded from highland areas as they extend southwards, while southern species become limited to the highlands as they extend northwards. The cohesive north‐south turnover pattern is consistent with the idea of a single Afromontane biogeographical unit, which can be related to a tropical East African lowland unit through a complex pattern of species turnover.

Application of the critical loads approach in South Africa

South Africa is the most industrialised country in southern Africa and stands at some risk from negative pollution inapa~ To the authors' knowledge, this paper presents the first attempt to apply the critical loads approach on the African corainent; although sensitivity mapping has been performed for Africa and the rest of the world (Kuylerstiema etal, this conference). Actual sulphate and base cation deposition loads in Mpumalanga (formerly the Eastern Transvaal province of South Africa) were mapped from 16 monitoring sites. The region is characterised by long, dry periods with little rain, high evaporation (up to 8 nun per day) and low run-off (15% of MAP). Provisional critical load and exceedance maps were produced for the surface waters using the Steady-State Water Chenfistry Model and the Diatom model. Maps of soil sensitivity to acid deposition, based on bedrock lithology, soil chemical characteristics and land cover, were produced. A weathering rate of 0.39-0.86 keq/ha/year was calculated for the most sensitive sites and taken as the critical load, based on the assumption that the weathering rate represents the buffering ability of the system. The critical loads were contrasted with measures of actual deposition to exanfine potential scenario's for critical load exceedances. Akey factor in refining the sensitivity nmps, and allowing estimation of the critical loads, is the accurate calculation of weathering rates under the warmer and more arid environmontal conditions prevalent in South Africa. In a developing country such as South Africa, where research resources are limited, the critical loads approach is a valuable means of assessing the risk of potential impacts of atmospheric deposition. South Africa is recognised as having comparatively high levels of air pollution emissions, particularly in the Eastern Transvaal Highveld. The total SO2 emission rate for the whole of South Africa is estimated to be 2.9 million tons per annum, of which 1.2 million tons are produced by coal-burning power stations. 75 % of these power stations are located in Mpumalanga (tbmlerly the Eastern Transvaal) (Annegarn et al, 1994; Tyson et al, 1988, Turner, pers. comm.). If the needs of South Africa as a developing nation are considered, the requirements tbr econonfic ~a'ox~N and associated employment, education, housing, and primary health cm'e, greatly overshadow issues relating to air pollution and its impacts. Since the critical loads approach can provide a basis on which cost-effective decisions can be made by regional and national authorities with respect to air quality, its potential use in South Africa was investigated. This paper presents the results of a pilot study to investigate the application of the critical loads approach in South Afi-ica.

Relationship between surface, free tropospheric and total column ozone in two contrasting areas in South Africa

Measurements of surface ozone in two contrasting areas of South Africa are compared with free tropospherc and Total Ozone Mapping Spectrometer (TOMS) total column ozone data. Cape Point is representative; of a background monitoring station which is remote from pollution impacts, whereas the Eastern Transvaal Highveld (ETH) stations of Elandsfontein and Verkykkop are situated in an area of intense urban and industrial activity. At Cape Point the diurnal cycle in surface ozone is small, the seasonal cycle shows a winter maximum and a summer minimum. In contrast, the ETH stations show a spring maximum in surface ozone with evidence of a summer enhancement. Comparison with Cape Point data suggests that photochemical ozone production accounts for about 50% of the background value. Seasonal variations in total ozone are consistent over the whole of South Africa, indicating a cycle which is independent of varying surface ozone concentrations. The spring maximum in free tropospheric ozone (up to 12 km) over the interior of South Africa is thought to be due to long-range transport of biomass burn products from latitudes to the north, rather than the extension of a localised surface photochemical influence through the troposphere.

Occurrence of bacterial brown spot of dry beans in the Transvaal province of South Africa

Bacterial brown spot, caused by Pseudomonas syringae pv. syringae, caused epidemics on dry beans (Phaseolus vulgaris) on the Transvaal Highveld in South Africa during 1992. Crop losses of up to 55% were reported in plantings of the dry bean cultivar Bonus. The pathogen was detected in commercial seed stocks.

The Wood Properties and Qualities of Three South African-Grown Eucalypt Hybrids

SYNOPSIS Hybridisation is becoming an increasingly important technique in tree breeding to improve yields, adaptability and wood quality. In this study, sample material from crosses of Eucalyptus grandis with E. tereticornis, E. camaldulensis and E. urophylla established on sites of which some are not normally suitable for E. grandis, was examined. The main aim was to assess the performance of these hybrids under varying site conditions using E. grandis as a control. At the age of five years samples were taken from six sites. One was established in the eastern Cape (near Stutterheim), two on the eastern Transvaal highveld (near Amsterdam and Jessievale), two in the northeastern Transvaal (near Tzaneen and Soekmekaar) and one in Zululand. Two trees of the best performing clones (judged over all six sites) from each hybrid were taken at random at each site, with two trees of an E. grandis clone to serve as a control. Aspects examined included split development and behaviour due to growth stresses, differenc...

Grazing trials with sheep on kikuyu(Pennisetum clandestinumChiov.) foggage in the eastern Transvaal highveld

Abstract Sheep performance and patterns of herbage utilization were determined in two grazing trials involving different amounts and quality of kikuyu foggage. In both trials each paddock of a series of paddocks of each foggage type was grazed successively. Amounts of leaf and stem, and the digestible organic matter and crude protein contents of these components, were determined at the start and end of grazing in each paddock. In one trial, wether lambs maintained livemass whereas, in the other, dry ewes and wether lambs both lost 8–10% of their initial mass, irrespective of differences in foggage quality. Grazing capacity was proportional to the yield of foggage. Although the percentage leaf in the foggage in the different treatments varied from 72 to 89, only some 50% of the total herbage was utilized. The estimates of quality indicated that a higher level of utilization would have resulted in poorer sheep performance.

Respiratory health status of children in the Eastern Transvaal Highveld

Respiratory health status of children in the Eastern Transvaal Highveld

The value of subtropical grass pastures for use as foggage on the eastern Transvaal Highveld

The utilization of frosted herbage of Pennisetwn clandestinwn, Paspalum notation, Digitaria eriantha, Cynodon sp. and Chloris gayana by Merino wethers during the winter confirmed the potential of this practice as an alternative winter feeding strategy under Highveld conditions. P. clandestinwn and P. notatum provided good quality foggage with average daily gains of 60–80 g sheep−1 being recorded. D. eriantha also provided good quality foggage when stem production was minimized. C. gayana gave good livestock performance, but did not persist under Highveld conditions. Although Cynodon sp. proved to be a relatively poor foggage species, it provided for the maintenance of livemass. Longer rest periods in the growing season increased the available pasture, grazing capacity and livestock production ha−1, but increased the probability of poorer livestock performance. This is probably linked with a lower protein content and a higher proportion of stem material in herbage rested for a longer period.

A survey of grazed and ungrazed grassland in the south‐eastern Transvaal highveld 2. Potential floristic composition and patterns of degradation

The floristic composition of selected veld communities which by virtue of their location were ungrazed, but regularly burned, and which were judged to reflect potential floristic composition, was measured at 112 sites in the south-eastern Transvaal Highveld. Relevant environmental parameters were established for each site and the composition of the adjacent grazed veld was determined; The floristic composition of selected veld communities which, by vitue of their location were ungrazed but regularly burned, and which were judged to reflect potential floristic composition, was measured at 112 sites in the south-eastern Transvaal highveld. Relevant environmental parameters were established for each site and the composition of the adjacent grazed veld was determined. The potential floristic composition appears to conform to part of a eutrophy-dystrophy gradient, with Themeda triandra most abundant in the relatively eutrophic environments. Patterns of degradation in grazed communities, involving undesirable floristic changes, were found to differ between eutrophic and dystrophic environments.Language: English Keywords: Environmental parameters; Eutrophy-dystrophy gradient; Grazed stands; Grazed veld; Intermediate grasses; Palatable grasses; Ungrazed stands; Ungrazed veld; Unpalatable grasses; grassland; floristic composition; degradation; themeda triandra; veld communities; transvaal highveld; south africa; botany

A survey of grazed and ungrazed grassland in the south‐eastern Transvaal highveld 1. Palatability composition and grazing capacity

The floristic composition of selected veld communities which by virtue of their location were ungrazed, but regularly burned, and which were judged to reflect potential floristic composition, was measured at 112 sites in the southeastern Transvaal highveld. At each site the composition of the adjacent grazed veld was also determined. Species were classified as palatable, intermediate or unpalatable and the percentages of these components were calculated for each of the 224 stands. By using previously established weighting values, namely, 3; 2 and 1 for the three components, a weighted palatability composition (WPC) value was derived for each community. Changes in the proportions of the palatability classes along the WPC gradient, as well as the frequency distributions of WPC values and grazing capacity on grazed and ungrazed stands, are presented.

An autoregressive atmospheric dispersion model for fitting combined source and receptor data sets

A method is developed for recursive prediction of emissions and concentrations at various positions, which obey an atmospheric dispersion model, yet have a least squares deviation from observations at the same points. As a by-product, the technique yields a concentration distribution grid on each time-step. This robust procedure rationalizes data which are in dispute, and makes optimal use of incomplete source or receptor observation records. Thus several unknown source-rates may be estimated on-line as the procedure steps through the remaining observation records. An accurate advection-diffusion solution is formulated as a linear transformation for each time-step, using a sub-grid adaptation of the pseudospectral method. This is extended to the vertical dimension using the zeroth, first and second vertical moments of concentration, allowing only uniform wind profiles, but gradual wind-field and diffusivity variations in the horizontal. A discrete Kaiman filter then provides optimal estimates of all source rates, constituting the state vector, to minimize deviations from any source and receptor observations. The algorithm has been applied in a 90 km × 90 km region of the Eastern Transvaal Highveld, including nine SO 2 sources and eight detectors. Indications are that the method will be a valuable aid in interpreting such data sets.

Variation in Wood Properties ofEucalyptus nitensin a Provenance Trial on the Eastern Transvaal Highveld in South Africa

SYNOPSIS Eucalyptus nitens is one of the four important cold-tolerant eucalypts grown for mining timber and pulpwood on the eastern Transvaal highveld in South Africa. In 1983 an active genetic improvement programme was initiated to improve growth rate, stem form and wood quality of this species. The most important wood properties that influence wood quality are splitting, collapse, and density. Little is known about the amount of variation and the magnitude of correlations between these wood properties. An eleven-year-old provenance trial of E. nitens was chosen for an investigation into the between- and within-tree variation and correlations between density, moisture content, spirality, percentage heartwood, taper, collapse, and splitting. Results from this study indicated large between- and within-tree variation for many of the wood properties measured. Seedlot differences were only detected for density, moisture content, percentage heartwood, and collapse. Density and taper generally increased with in...

Workshop on the air pollution situation in the Eastern Transvaal Highveld and neighbouring regions

Workshop on the air pollution situation in the Eastern Transvaal Highveld and neighbouring regions

AN EFFICIENCY COMPARISON BETWEEN PART-TIME AND FULL-TIME FARMERS ON THE TRANSVAAL HIGHVELD

ABSTRACT Three groups of farmers on the Transvaal Highveld were compared: Full-time farmers, part-time farmers entering the industry with the aim of eventually becoming full-time farmers and persons intending to farm part-time on a permanent basis. Management indices based on production functions indicate that full-time farmers were most efficient entrepreneurs and those who intend to farm part-time permanently the least efficient. The general organisation of full-time farmers appears to be better than that of part-time farmers. The difference between the two groups of part-time farmers appears to be operational in nature. Those intending to become full-time farmers fared better in most individual enterprises than permanent part-time farmers.

Provenance Variation ofEucalyptus nitenson the Eastern Transvaal Highveld in South Africa

SYNOPSIS Eucalyptus nitens is a promising species for commercial afforestation in the cooler-temperate, humid region of South Africa where frosts are moderate to severe. In a trial of 12 provenances representing most of the entire natural range of the species and established at two locations on the Eastern Transvaal Highveld, the provenances from New South Wales, Australia, had greater height, diameter at breast height and volume growth after four years than the provenances from Victoria, Australia. All provenances were affected by a leafspot disease on the juvenile foliage caused by Mycosphaerella nubilosa, formerly identified as M. molleriana, which leads to premature defoliation. The New South Wales provenances had less defoliation than the Victorian provenances. Results from this trial and other trials in South Africa have been used to recommend further testing of populations within all New South Wales provenances.

Exploratory trials on reinforcement of veld with legumes in the south‐eastern transvaal highveld

Abstract The feasibility and potential of reinforcing veld with legumes in the south‐eastern Transvaal highveld was assessed in a number of trials during the period 1974–84. Experience was gained with regard to methods of establishment, adaptation of legumes to the local environment, responses to fertilization, especially with lime and superphosphate, and the reaction of legumes to fire and grazing. In all, 17 legumes were involved, including the genera Coronilla, Desmodium, Glycine, Lespedeza, Lotus, Macroptilium, Medicago, Neoto‐nonia, Trifolium and Vigna. Only Coronilla varia (crownvetch) showed a satisfactory degree of persistence. However, crownvetch is slow to establish, is intolerant of waterlogging and has a relatively high requirement for lime and phosphate. Considering these features, and the probability of undesirable changes in grass species composition in reinforced veld, it is recommended that intensification be achieved through development of improved pastures for use in conjunction with veld, rather than by means of veld reinforcement.

The characterization of irrigated Midmar Italian ryegrass in the South Eastern Transvaal Highveld using slaughter lambs

Reports the results of a study conducted to characterize the seasonal growth rate and changes in the quality of herbage, animal production and grazing capacity of Midmar Italian ryegrass in the South Eastern Transvaal Highveld under continuous grazing; Four levels of available dry matter (DM) were maintained on a continuously grazed irrigated Midmar Italian ryegrass ( Lolium multiflorum Lam. ) Pasture by means of a put-and-take grazing procedure. The pasture was stocked with three successive sets of weaned lambs in winter, spring and early summer respectively. The relation between average daily gains (ADG) and available DM was positively linear. At equivalent levels of available DM, gains were greater in spring than in either the winter and summer periods (P Keywords: Animal production; average daily gain; Continuous grazing; crude protein content; Dry matter; ermelo district; Grazing capacity; growth rate; Herbage availability; italian ryegrass; Lolium multiflorum ; Midmar Italian ryegrass; organic matter; Seasonal growth rates; Slaughter lambs; south africa; stocking rates; Transvaal Highveld Journal of the Grassland Society of Southern Africa.

Some characteristics of storms on the transvaal highveld

AbstractStorm climatological statistics were extracted from digitized weather radar records. The effects of using various definitions for storm cells were small for most attributes and data from 20 to 30 days spread over a few years gave representative results. Only a few per cent lasted for more than an hour and about half of all cells travelled slower than 25 km h−1. Cells defined by the 45 dBz contour at 5 to 8 km above mean sea level lasted on average 18 minutes and travelled at 26 km h−1, compared to 20 minutes and 23 to 31 km h−1 in north‐eastern Colorado. The distributions of speeds, lifetimes and areas for the Transvaal were also similar to those for Colorado and they were nearly log‐normal. There was a wide range of cell behaviour from day to day and for storms on individual days.