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Financial Decision Criteria and Real Price Changes
Item type: Journal Article • Journal: South African Forestry Journal • Authors: H. J.E. Uys --- Department of Forest Science,General price indices such as the Consumer Price Index (CPI) or the Production Price Index (PPI) represent the weighted average of prices of a large number of goods and services. Such price indices therefore cannot accurately measure the changes in... -
Stimulation of Bud Production in Eucalyptus globulus by Paclobutrazol Application
Item type: Journal Article • Journal: South African Forestry Journal • Authors: S. Hetherington --- , K.M. Jones --- Department of Primary Industries New Town Research Laboratories, Australia T.B. Koen --- Department of Primary Industries New Town Research Laboratories, AustraliaTrunk injection of paclobutrazol (Clipper) significantly increased the bud crop on 7-year-old Eucalyptus globulus (Labill.) seed orchard trees, within one year of application. This is the first reported stimulation of reproduction to occur, with eucalypts, in the season of application... -
The Hydrological Effects of a Wildfire in a Eucalypt Afforested Catchment
Item type: Journal Article • Journal: South African Forestry Journal • Authors: D.F. Scott --- Division of Forest Science and Technology, Jonkershoek Forestry Research Centre, RSA R.E. Schulze --- Department of Agricultural Engineering, RSAA high-intensity wildfire through a humid, upland catchment which was partially afforested to Eucalyptus fastigata, markedly increased stormflows and caused high soil losses off the afforested slopes. Total streamflow yield was unchanged but baseflow was reduced after the fire. The... -
Land Valuation with a Limited Planning Horizon
Item type: Journal Article • Journal: South African Forestry Journal • Authors: H. J.E. Uys --- Department of Forest Science, H. Kotze --- Department of Forest Science,The forestry industry in South Africa operates within a dynamic environment. Rotations are relatively short, land use conversion takes place regularly and company ownership changes frequently. Foresters in the private sector are therefore reluctant to use Land Expectation Value with... -
A Field Demonstration of the Effect on Streamflow of Clearing Invasive Pine and Wattle Trees from a Riparian Zone
Item type: Journal Article • Journal: South African Forestry Journal • Authors: P.J. Dye --- Division of Forest Science and Technology, A.G. Poulter --- Division of Forest Science and Technology,Two portable weirs were used to quantify changes in streamflow following clearfelling of a dense stand of self-sown Pinus patula and Acacia mearnsii along a riparian zone on Kalmoesfontein, a SAPPI forest plantation south-east of Lydenburg, Eastern Transvaal. The weirs... -
Growth patterns of Italian ryegrass cultivars established in different seasons
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: D.C.W. Goodenough --- Department of Agriculture (Natal Region), C.I. Macdonald --- Department of Agriculture (Natal Region), A.R.J. Morrison --- Department of Agriculture (Natal Region),A comparison is made between various Italian ryegrass cultivars established under irrigation on a well‐drained upland site during the traditional autumn months, with plantings of the same cultivars at other times of the year. -
The influence of nitrogen fertilization, spring burning and height of stubble on hay and seed production of eragrostis curvula 1
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: N.F.G. Rethman --- Department of Plant Production, B.H. Beukes --- Department of Agriculture & Water Supply,This investigation, conducted over a three‐year period, emphasized the strong effect of nitrogen fertilization on both hay and seed production. The optimum level of nitrogen, for conditions on the Eastern Highveld being 100–150 kg N/ha applied in spring, followed by... -
Forage potential of Japanese radish (Raphanus sativus) as influenced by planting date and cultivar choice
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: A. Verschoor --- Division of Grassland Science, Department of Plant Production, Republic of South Africa N.F.G. Rethman --- Division of Grassland Science, Department of Plant Production, Republic of South AfricaJapanese radish shows potential as a winter forage. If planted early (Dec/Jan.), high temperatures can damage seedlings. With late plantings (Mar./Apr.), the growing season can become a limiting factor. A study to establish the optimum planting date for warmer areas... -
Influence of temperature and daylength on the phenological development of annual Medicago species with particular reference to M. truncatula, cv. Jemalong
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J.M. van Heerden --- Department of Agriculture,In a glasshouse and two growth-room trials, carried out in conjunction with 12 serial plantings in pots in the open, it was found that the phenological development of Medicago truncatula, M. tornata, M. aculeata, M. polymorpha, M. scutellata and M... -
Effect of planting date on the phenology, seed yield, and fatty acid composition of three sunflower (Helianthus annuus L.) cultivars
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: R.N. de Vos --- , J. Dreyer --- , J.D. Lea --- Department of Crop Science,Four planting dates (early October to mid-January) were used to obtain a range of environmental conditions for growing three sunflower cultivars. The effect of planting date on phenological development was small compared to that of genotype though the hybrid S0404... -
Invloed van bemesting op die oliekonsentrasie oliekwaliteit van sonneblomsaad
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H.L. Loubser --- Olie- en Proteïensadesentrum, Departement Landbou en Watervoorsiening, C.L. Grimbeek --- Olie- en Proteïensadesentrum, Departement Landbou en Watervoorsiening,Influence of fertilization on the oil concentration and oil quality of sunflower seed. Fertilizer trials (N,P,K and lime) were conducted over two seasons at three localities. Results indicate that 150 kg N ha−1 fertilizer decreased the oil concentration of the... -
'n Nuwe benadering tot die bepaling van hitte-eenhede vir sonneblom
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H.L. Loubser --- ,Die konvensionele metode vir die bepaling van hitte-eenhede is vergelyk met 'n nuwe benadering. Data uit sewe kultivarproewe insluitende daaglikse maksimum en minimum temperature is gebruik om die hitte-eenhedevereistes van drie kultivars te bepaal. Twee vergelykings is gebruik, een verteenwoordig... -
The influence of photoperiod and temperature on the pre-flowering phase length of eleven soybean cultivars in northern Natal
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. Chapman --- Agricultural Research Station,The effect of photoperiod and temperature on the pre-flowering phase length of 11 soybean cultivars was studied. Heat units (10 to 30°C) and night hours (sunset to sunrise) were used as measures of temperature and photoperiod respectively. Highly significant negative... -
Die effek van plantpopulasie op die saadopbrengs van sonneblomkultivars
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H.L. Loubser --- , C.L. Grimbeek --- , L. A.S. Robertson --- , Beulah Bronkhorst --- , C. Serfontein --- , J.C. van der Sandt --- ,'n Aantal sonneblombasters is vergelyk by drie plantpopulasies oor twee seisoene te Ermelo, Sandvet en Warmbad. Die doel was om die kompensasievermoë van kultivars te bepaal vir 'n swak stand. Onder laepotensiaal-toestande was die kultivar X plantpopulasie-interaksie nie beduidend nie,... -
Invloed van bemesting op sonneblomme. I. Saadopbrengs
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H.L. Loubser --- , Republiek van Suid-Afrika C.L. Grimbeek --- , Republiek van Suid-Afrika Beulah Bronkhorst --- , Republiek van Suid-AfrikaBemestingsproewe is by drie lokaliteite oor vier seisoene uitgevoer deur 'n ongerepliseerde 43-gestrengelde faktoriaaluitleg te gebruik. Peile het gewissel van 0 tot 150 kg N ha−1, 0 tot 45 kg P ha−1, 0 tot 60 kg K ha−1 by twee... -
Variasie in lipied- en proteïeninhoud van sonneblomsaad en oliekoekmele in Suid-Afrika
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: G.A. Smith --- Departement Veekunde, Republiek van Suid-Afrika J.P. Hayes --- Departement Pluimveekunde, Republiek van Suid-Afrika Naomi Smith --- Navorsingsinstituut vir Vee- en Suiwelkunde, Republiek van Suid-AfrikaDie variasie in die chemiese samestelling van sonneblom- saad, wat uit verskillende areas aan oliepersers gelewer is, en die invloed daarvan op die samestelling van die geproduseerde oliekoekmele is in die studie ondersoek. Die ontleding van die sade het 'n... -
Bepaling van donkerrespirasie by mielies (Zea mays L.)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: W.H. du Preez --- Landboufakulteit, Republiek van Suid-Afrika J.J. Human --- Landboufakulteit, Republiek van Suid-Afrika L.P. de Bruyn --- Landboufakulteit, Republiek van Suid-AfrikaTwee mieliecultivars wat in potte onder glashuistoestande met optimale watervoorsiening gekweek is, is gedurende die agtblaarstadium en stuifmeelstort tot baardverskyning aan stremming onderwerp deur watertoediening te weerhou. Die CO2-uitvloeitempo is op sekere tye gedurende die nagperiode gemonitor. Hierdie waardes het... -
Effect of a foliar application of paclobutrazol in autumn on the reproductive development of ‘Songold’ plum
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: O.J. Olivier --- Department of Horticultural Science, Republic of South Africa G. Jacobs --- Department of Horticultural Science, Republic of South Africa D.K. Strydom --- Department of Horticultural Science, Republic of South AfricaA foliar application of paclobutrazol (1- (4-chlorophenyl) −4,4-dimethyl-2- (1,2,4- triazol-1-yl) pentan-3-ol) at 250 or 500 mg dm−3 a.i. in autumn, or late winter applications of dinitro-o-cresol oil emulsion (DNOC) in water at 3% v/v, increased the percentage of ‘Songold’ plum... -
The importance of certain insects as pollinators of sunflower (Helianthus annuus L.)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.P. du Toit --- , Republic of South AfricaThis study reports the effects of Apis mellifera L. (honeybees), Astylus atromaculatus Blanchard (spotted maize beetles), Heliothis armigera Hübner (American bollworm larvae) and Musca domestica L. (house flies) on seed set in commercial sunflower. The pollination efficiency of these insects... -
Diversity, abundance and behaviour of diurnal insects on flowering capitula of commercial sunflower in the Transvaal
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.P. du Toit --- Apicultural Unit, Republic of South Africa E. Holm --- Department of Entomology, Republic of South AfricaSunflower, Helianthus annuus L., is an insect-pollinated crop and the different insect taxa visiting the flowering head play a role of greater or lesser importance in cross-pollination. Species diversity, abundance and behaviour of insects visiting commercial sunflower during flowering are... -
An automated colorimetric method for the determination of dicyandiamide in 1.0 M KCI soil extracts
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: D.C. Pretorius --- , Republic of South Africa J.F. van Staden --- Department of Chemistry, Republic of South Africa A. D.P. Botha --- , Republic of South Africa C. Kolver --- , Republic of South AfricaThe nitrification inhibitor dicyandiamide (cyanoguanidine, didin or DCD) reacts with 1-naphthol and diacetyl to form a red complex which measures spectrophotometrically at 540 nm. An automated analytical procedure was developed to determine DCD in soils extracted with 1.0 M KCI... -
Bepaling van optimale blom en plantdatums vir koring in die sentrale besproeiingsgebiede van die RSA met behulp van 'n groeimodel
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A. Singels --- Departement Landbouweerkunde, Republiek van Suid-AfrikaOptimale blom- en plantperiodes vir besproeiingskoring is bepaal vir 15 lokaliteite in die sentrale besproeiingsgebiede van die RSA deur gebruik te maak van historiese temperatuurdata en die PUTU koringgroeimodel. Die hoogste gemiddelde opbrengs is gesimuleer met blomperiodes wat oor die... -
Pistilloidy in common wheat resulting from a spontaneous mutation
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: G.F. Marais --- Department of Genetics and Institute for Biotechnology, South Africa B. Lombard --- , Republic of South AfricaA plant that produced more than one kernel in many of its florets was isolated from breeding material. The condition was found to be transmitted in monogenic fashion as a recessive character. Transmission of the mutation through the egg cells... -
Evidence that alachlor selectivity in sunflower is based on depth-protection
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. Allemann --- Department of Plant Production and Soil Science, Republic of South Africa C.F. Reinhardt --- Department of Plant Production and Soil Science, Republic of South AfricaThe relative importance of the underground shoot parts (hypocotyl) and roots of sunflower (Helianthus annuus L.) seedlings on the absorption of alachlor [a-chloro-2′,6′-diethyl- N-(methoxymethyl) acetanilide] was studied in a glasshouse experiment. A layer of activated charcoal divided the soil in... -
High availability of alachlor affects the roots and general growth of sunflower seedlings
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. Allemann --- Department of Plant Production and Soil Science, Republic of South Africa C.F. Reinhardt --- Department of Plant Production and Soil Science, Republic of South AfricaThe tolerance to alachlor [α-chloro-2′,6′?diethyl-N-(metoxy- methyl) acetanilide] of three sunflower (Helianthus annuus L.) cultivars was evaluated in an aqueous medium in a glass- house. Alachlor (0.79 - 6.32 mg L−1) caused significant reductions in the root and shoot growth of... -
The effect of a diurnal period of supra-optimal temperature on the seed vigour of sunflower
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South AfricaThe daily maximum temperature in the upper 20 mm of sandy soils is often higher than 45°C on cloudless days during November, December and January in the summer rainfall region of South Africa. At these supra-optimal temperatures, sunflower seedling vigour... -
The response of germinating sunflower seed to heat tolerance induction
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South AfricaVigour of pre-emergent sunflower (Helianthus annuus L.) seedlings is reduced when daily peak soil temperatures exceed 44°C resulting in poor emergence. Seedlings of sorghum (Sorghum bicolor L. Moench) are known to acquire thermotolerance to temperatures of 45–50°C as a consequence... -
Die invloed van die voginhoud op die dopbaarheid van sonneblomsaad
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republiek van Suid-Afrika H.L. Loubser --- , Republiek van Suid-Afrika P.S. Hammes --- Departement Plantproduksie en Grondkunde, Republiek van Suid AfrikaDie voginhoud van sonneblomsaad (Helianthus annuns L.) wat vir persing gebruik word, wissel tussen 5.5% (ongeveer die laagste inhoud waartoe saad natuurlik droog) en 10% (die hoogste toelaatbare inhoud vir berging). Die doel van die ondersoek was om vas te... -
Die sif van sonneblomsaad vir die verbetering van olie- en proteienherwinning
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republiek van Suid-Afrika H.L. Loubser --- , Republiek van Suid-Afrika P.S. Hammes --- Departement Plantproduksie en Grondkunde, Republiek van Suid-AfrikaVoor die olie van sonneblomsaad (Helianthus annuus L.) uitgepers word, word dit ontdop om onder andere die kwaliteit van die oliekoek so hoog moontlik te kry. Dopbaarheid, of die gemak van ontdopping, het 'n positiewe verwantskap met saadgrootte. Aangesien saadmonsters... -
The effect of plant population on the quality of sunflower seed for processing
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaAmong other disadvantages, low hullability of sunflower seed results in oil cake with a high fibre and low protein content. Hullability is known to increase with increased seed size. Seed size generally decreases with an increase in plant density. The... -
Preliminary investigation on the potential of Clivia miniata Regel as a cut flower
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: P.J. Robbertse --- Department of Plant Production and Soil Science, Republic of South Africa C.B. Honiball --- Department of Plant Production and Soil Science, Republic of South AfricaClivia miniata Regel is widely cultivated as a garden ornamental and a pot plant. It occurs in many attractive shades of orange, red, yellow and pink but little information exists regarding its use as a cut flower. The possibility of... -
Optimisation of transient transformation of a South African spring wheat cultivar with particle bombardment
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: S.M. de Villiers --- , Republic of South Africa Y. Laib --- Centre de Developement des Techniques Nuclear, AlgeriaTransient transformation was optimised for bread wheat, Triticum aestivum L. cv Kariega, using a particle inflow gun constructed at ARC-Roodeplaat. Excised immature embryos, cultured in vitro for 5 to 7 days, were bombarded with pAHC25 and analysed for the presence... -
The effect of environment and cultivar on sunflower seed. I. Yield, hullability and physical seed characteristics
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaThe quality of South African sunflower oil cake varies and often has an unacceptably low protein and high crude fibre content. Poor hullability of the seed is generally regarded as the primary cause thereof. This study examines the contribution of... -
The effect of environment and cultivar on sunflower seed. II. Composition and processing quality
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaThe processing quality of sunflower seed is determined by its oil yield, oil cake yield and oil cake composition. Quality of the oil cake is determined by its protein and crude fibre content. Seed composition is affected by both cultivar... -
The yield and processing quality of sunflower seed as affected by the amount and timing of nitrogen fertiliser
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaThe response of sunflower (Helianthus annuus L.) seed yield and seed processing quality to the amount and timing of nitrogen were studied in a field trial. Nitrogen application rates were 20, 70 and 120 kg ha−1 with limestone ammonium nitrate... -
The effect of water stress during grain filling on the yield and processing quality of sunflower seed
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaThe oil and protein contents of sunflower seed are affected by water stress. Hullability is a seed quality trait which affects the efficiency of oil extrusion and the quality of the oil cake produced from the seed. Apart from cultivars,... -
Low temperature treatment advances flowering in Clivia miniata (Lindley) Regel
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.B. Honiball --- Department of Plant Production and Soil Science, P.J. Robbertse --- Department of Plant Production and Soil Science,Clivia miniata plants were exposed to a cold treatment of 7.5–10 °C for 14 days in the dark from 24 April 2000. Compared to the non-cold treated control plants, the cold-treated plants started flowering four weeks earlier resulting in 80%... -
Effects of early winter gibberellic acid and mineral oil applications on flowering of young non-bearing clementine (Citrus reticulata Blanco.) and satsuma (Citrus unshiu Marc.) trees
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: M.J. Mudzunga --- Department of Horticultural Science, South Africa K.I. Theron --- Department of Horticultural Science, South Africa E. Rabe --- Department of Horticultural Science, South AfricaGibberellic acid (GA3) and heavy mineral oil (Bac-oil) treatments, either individually or in combination, applied during the flower initiation period in early winter (April to July) were evaluated as a means to reduce flowering levels in young non-bearing citrus trees... -
Effects of nutrient regime on bulb yield and plant quality of Lachenalia Jacq. (Hyacinthaceae)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F. Roodbol --- , South Africa E. Louw --- , South Africa J.G. Niederwieser --- , South AfricaThe effects of different nutrient regimes on the Lachenalia cvs ‘Romelia’ and ‘Namakwa’ were studied over two successive seasons. The basic formulation of the Commisie Glastuinbouw (1992), viz 0.37 g KNO3 + 0.36 g Ca(NO3)2 + 0.06 g MgS04 +... -
Grondgeassosieerde, lineêre plantegroeipatrone in die Warmbadomgewing van die Limpopo-provinsie van Suid-Afrika
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J.J. Dinkelmann --- Departement Geografie en Omgewingstudies, E. Verster --- Departement Geografie en Omgewingstudies, T.H. van Rooyen --- Departement Geografie en Omgewingstudies,Lineêre mikroreliëfverskynsels wat op lugfoto's soos vingerafdrukpatrone vertoon en bestaande uit boomryke kruine en grasryke trôe is op die voethang van die Baviaansberg, Warmbadomgewing (Suid-Afrika) beskryf. Vir die doel om die oorsprong van die verskynsels te verklaar is van 'n... -
Development and validation of relationships between sunflower seed quality and easily measurable seed characteristics for grading purposes
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- , Republic of South Africa H.L. Loubser --- , Republic of South Africa P.S. Hammes --- Department of Plant Production and Soil Science, Republic of South AfricaSunflower seed delivered by farmers is usually traded without taking seed quality into account, owing to the lack of a quick and inexpensive method for quality assessment at delivery points. Seed quality parameters (oil content, protein content, hullability and amount... -
Effects of nutrient supply on nutrient element content of two lachenalia cultivars
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F. Roodbol --- , Republic of South Africa J.G. Niederwieser --- , Republic of South AfricaThe N, K, Ca, P and Mg content (% dry mass) of bulbs and leaves of two lachenalia cultivars, Romelia and Namakwa, was determined at different application levels of a basic nutrient formulation to develop norms for tissue analysis and... -
Evaluation of maize cultivars and rotation crops for resistance to damage by fungus-growing termites
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H.F. Riekert --- , South Africa J. van den Berg --- , South AfricaThe fungus-growing termites, Microtermes spp. and Allodontermes spp. are important maize pests in sub-Saha- ran Africa. The use of sunflower and sorghum as alternate or rotation crops with maize to reduce termite infestations was evaluated in field trials in South... -
Weed survey in cotton (Gossypium hirsutum L.) and sunflower (Helianthus annuus L.) fields in the Pandamatenga plains of northeastern Botswana
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.E. Abdullahi --- Department of Agricultural Research, BotswanaSunflower and cotton fields in the Pandamatenga plains of northeastern Botswana were surveyed in 1998 and 1999 for weed infestations. Twenty-seven and 24 species were identified from the fields in 1998 and 1999, respectively. Nineteen and 17 species were found... -
Potassium nitrate and urea sprays affect flowering and yields of ‘Tommy Atkins’ (Mangifera indica) mango in Ethiopia
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: T. Yeshitela --- Department of Plant Production and Soil Sciences, South Africa P.J. Robbertse --- Department of Plant Production and Soil Sciences, South Africa P. J.C. Stassen --- Department of Horticulture, South AfricaThe effects of leaf applications of potassium nitrate (KNO3), alone and in combination with urea at different concentrations on flowering, fruit set and fruit quality of Tommy Atkins' mango grown in the rift valley of Ethiopia were evaluated. The trees... -
Chemical control of Nysius natalensis Evans (Hemiptera: Orsillidae), a pest of sunflower in South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: H. du Plessis --- , South Africa M.J. Byrne --- Ecophysiological Studies Research Group, South Africa J. van den Berg --- School of Environmental Sciences and Development, South AfricaNo insecticide is currently registered for Nysius natalensis Evans (Hemiptera: Orsillidae), control on sunflower [Helianthus annuus L. (Asteraceae)]. Field as well as laboratory trials were conducted to evaluate efficacy of insecticides for N. natalensis control. During budding prior to anthesis,... -
The effect of MCPA and paclobutrazol on flowering, berry set, biomass production, tuber yield and quality of potato
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: T. Tekalign --- Department of Plant Production and Soil Science, South Africa P.S. Hammes --- Department of Plant Production and Soil Science, South AfricaThe effects of MCPA and paclobutrazol on potato (Solanum tuberosum L.) flowering, berry formation, dry matter production and allocation, tuber yield and quality were investigated under greenhouse and field conditions at the Experimental Farm of the University of Pretoria. Both... -
Screening of South African sunflower (Helianthus annuus L.) cultivars for alachlor sensitivity
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: J. Allemann --- Department of Soil, Crop and Climate Sciences, South Africa G.M. Ceronio --- Department of Soil, Crop and Climate Sciences, South AfricaOccasionally a herbicide that is considered safe to use at prescribed rates causes damage to crop plants at those same rates. Alachlor (Lasso EC®) is registered for use on sunflower at a rate of 1.5 to 1.92 kg ai ha−1... -
Redox conditions related to interflow in a soil of the Kroonstad form in the Weatherley catchment
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: K. Jennings --- , South Africa P.A.L. Le Roux --- , South Africa C.W. Van Huyssteen --- , South Africa M. Hensley --- , South Africa T.B. Zere --- , South AfricaThe Kroonstad soil form, in the Weatherley catchment, Eastern Cape Province consists of an orthic A / E / G horizon sequence, and is a typical gleyed soil of South Africa. The profile has an uncommon diffuse E / G... -
Grain yield and rainfall use efficiency responses of maize and alternative rotating crops under marginal production conditions in the western Highveld of South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A.A. Nel --- ,Crop rotation is known to enhance crop yields. It is therefore recommended, regardless of rainfall and soil type, as a counter measure for the risks associated with monoculture maize (Zea mays). Experience in the western Highveld where rainfall is low... -
Evaluation of electrical conductivity of the fertiliser solution on growth and flowering of a Cymbidium hybrid
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: SK Naik --- , India D Barman --- , India Rampal --- , India RP Medhi --- , IndiaThe effects of three fertiliser solutions (20:20:20, 15:5:25 and 12:30:10 NPK) with electrical conductivity (EC) of 1, 1.5 or 2 mS cm−1 on growth and flowering of Cymbidium ‘Sleeping Nymph’ were investigated over three years. One-year-old tissue-cultured propagules of ‘Sleeping... -
Elucidation of seasonal pigmentation patterns in the involucral leaves of Leucadendron ‘Safari Sunset’
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Michael Schmeisser --- Department of Horticultural Science, South Africa Gerard J Jacobs --- Department of Horticultural Science, South Africa Willem J Steyn --- Department of Horticultural Science, South AfricaThis study investigates seasonal pigmentation patterns found in the involucral leaves of Leucadendron ‘Safari Sunset’, with the long-term aim of colour manipulation. Treatments comprised deconed shoots and shoots in which the opening of the flower head was physically prevented. During... -
The effect of canola (Brassica napus) as a biofumigant on soil microbial communities and plant vitality: a pot study
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Clarissa Potgieter --- North-West University, South Africa Misha De Beer --- North-West University, South Africa Sarina Claassens --- North-West University, South AfricaCanola (Brassica napus) may be incorporated into soil as a biofumigant for control of pathogens such as Sclerotinia sclerotiorum. Yet, the effect of biofumigants on natural microbial communities required to maintain soil functions is still unclear. A pot experiment with... -
FUTURE CHALLENGES IN WATER QUALITY MODELLING WITH PARTICULAR REFERENCE TO OPERATIONALLY CLOSED CATCHMENTS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: S.F. Forster --- Department of Water Affairs, South Africa F.A. Stoffberg --- Department of Water Affairs, South Africa J.A. van Rooyen --- Department of Water Affairs, South AfricaAs a result of the declining quality of many water sources, the use of water quality models in planning is increasing. To date applications have involved the simulation of total dissolved salts and nutrients, largely in catchments affected by urban... -
UNDERSTANDING THE PHYSICAL STRUCTURE OF SOUTHERN AFRICA'S STANDING WATERS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: B.R. Allanson --- , South AfricaAn examination of the nature of the stratification in polymictic and monomictic Southern African reservoirs is presented. Wind stirring is the principal mode of heat transfer during spring heating. In high summer radiation from stable heated surface layers is responsible... -
CIRCULATION IN HIGHLY STRATIFIED SOUTHERN AFRICAN ESTUARIES
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: J.L. Largier --- , USA J.H. Slinger --- Council for Scientific and Industrial Research, South AfricaThe nature of estuarine circulation under highly stratified conditions is reviewed in the context of southern African estuaries that are small and have a constricted connection to the ocean. While the focus is on the generic hydrodynamic processes and features,... -
FURTHER COMMENT ON THE RESPONSE OF EASTERN CAPE PROVINCE ESTUARIES TO VARIABLE FRESHWATER INFLOWS
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: B.R. Allanson --- , South Africa G. H.L. Read --- , South AfricaRiver flow patterns in the Kariega, Great Fish and Keiskamma estuaries, South Africa are examined to assess the impact variation in flow has upon the delivery of inorganic nutrients, total organic carbon, primary productivity and the heterotrophic components, bacteria and... -
VARIABILITY IN THE INVERTEBRATE FAUNA OF AN INTERMITTENT STREAM OVER THREE CONSECUTIVE MIDSUMMER PERIODS
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: M. C. Uys --- , South Africa J. H. O'Keeffe --- , South AfricaNon-perennial rivers in semi-arid regions are exposed to unpredictable and highly variable rainfall and hydrology which can have considerable effects on faunal organisation at different scales. Spatial and temporal dynamics in the aquatic invertebrate fauna of an aseasonal intermittent river... -
A PRELIMINARY BIOCHEMICAL GENETIC STIJDY OF TWO POPULATIONS OF LITHOGNATHUS AURETI (PERCIFORMES: SPARIDAE)
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: F. H. van der Bank --- , , South Africa J. A. Holtzhausen --- , NamibiaTwo populations of Lithognathus aureti were electrophoretically analysed to determine the extent of genetic divergence between, and variation within them. Gene products of 35 protein coding loci showed no fixed allele differences between these populations. However, significant genotypic differentiation between... -
A REVIEW OF THE MACROBENTHIC FAUNA OF THE MHLATHUZE ESTUARY: SETTING THE ECOLOGICAL RESERVE
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: C. F. Mackay --- , , South Africa D. P. Cyrus --- , , South AfricaThis paper reviews historical and current ecological information on macrobenthos from the Mhlathuze Estuary before and after development of the Richards Bay Harbour. The fauna is described in terms of the potential influence of a change in freshwater inflow to... -
Research note: Vernalization requirements of Lolium multiflorum Lam. cv. Tetrone
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: A. Landman --- Agricultural Research Council, Republic of South Africa P.J. Robbertse --- Department of Botany, Republic of South Africa A. Smith --- Agricultural Research Council, Republic of South AfricaThis study was undertaken mainly to attempt to understand why Italian type plants of Lolium multiflorum Lam. (Italian ryegrass) fail to become vernalized in certain climatic regions of South Africa. The vernalization requirements of seed and plants for the induction... -
The minimum required yield for profitable sawtimber production from Pin us patula in the escarpment area of Mpumalanga
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: M.P. Falcão --- Faculty of Agronomy and Forestry Engineering, Mozambique H. J.E. Uys --- Department of Forest Science, South AfricaIn a recent study (1998) the minimum required yield for profitable sawtimber production from Pinus patula in the escarpment area of Mpumalanga was established. Net Present Value was used as financial profitability criterion. All cost components were 1996 costs (the... -
Fluid Dynamics of Parallel Plates Viscometer: a Case Study of Methods Of Series Summation
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: O.D. MakindeThe fluid dynamics of parallel plates viscometer is investigated mathematically using both the Navier-Stokes and continuity equations for an incompressible viscous fluid. The problem admits similarity solutions, thereby reducing the unsteady Navier-Stokes equations to a parameter dependent fourth order nonlinear... -
On boundary layer flow of a Sisko fluid over a stretching sheet
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Masood Khan --- Department of Mathematics, Pakistan Azeem Shahzad --- Department of Mathematics, PakistanIn this paper, the steady boundary layer flow of a non-Newtonian fluid over a nonlinear stretching sheet is investigated. The Sisko fluid model, which is combination of power-law and Newtonian fluids in which the fluid may exhibit shear thinning/thickening behaviors,... -
The IFR process: beyond the specialist workshop
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D Louw D Hughes A BirkheadThe process of determining Instream Flow Requirements (IFRs) has been well developed to the point at which an IFR table which quantifies the temporal distribution of discharge, upon which the modified flow regime is based, is produced. During the last... -
Some aspects of the ecology of the Groot Letaba River in the Northern Province, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: W Vlok JS EngelbrechtThe aim of this pilot study was to evaluate the current ecological status of the Groot Letaba River and to compare this information with historical data. The objective was to determine the effects of various impacts on the fish populations... -
The macroinvertebrates of the Cunene River from the Ruacana Falls to the river mouth and assessment of the conservation status of the river
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: FC de Moor HM Barber-James AD Harrison CR Lugo-OrtizThe proposed construction of a second hydroelectric power-generating dam on the Cunene (Kunene) River on the Namibia-Angola border, more than 100km downstream of the Ruacana hydroelectric power plant, will have a major influence on the aquatic biota of this river... -
The application of a hydraulic biotope matrix to the assessment of available habitat: Potential application to IFRs and river health monitoring
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: RA Wadeson KM RowntreeIn an attempt to meet the requirement of the new South African Water law a number of initiatives are under way to determine the flow requirements for our rivers. An essential component of this initiative is the determination of the... -
Beacons in the limnological landscape
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: BR AllansonAn overview is given of a number of major developments in the limnology of South Africa, Zimbabwe and Namibia. None was possible without the involvement of enthusiastic investigators who, over some 70 years, stimulated the growth of freshwater research in... -
Oualidia lagoon, Morocco: an estuary without a river
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: K Hilmi VG Koutitonsky A Orbi JI Lakhdar M ChagdaliThis study describes some physical oceanography features of an estuary maintained by fresh groundwater inflow. The mesoscale variability of currents, temperature and salinity are documented from moored current meter observations of 12 days duration at three stations. Current speeds exceeded... -
Estimation of preferred water flow parameters for four species of Simulium (Diptera: Simuliidae) in small clear streams in South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: NicholasA Rivers-Moore FerdinandC de Moor SharonA Birkholz RobertW PalmerBlackfly larvae typically occur in fast-flowing riffle sections of rivers, with different blackfly species showing preferences for different hydraulic conditions. Very little quantitative data exist on hydraulic conditions linked to the blackfly species occurring in South African streams. Stones-in-current biotopes... -
Application of the Indicators of Hydrological Alteration method to the Mkomazi River, KwaZulu-Natal, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: V Taylor --- , South Africa R Schulze --- , South Africa G Jewitt --- , South AfricaHydrological regimes play a major role in structuring the biotic diversity within river ecosystems and hydrological variation is recognised as a primary driving force within those ecosystems. The US Nature Conservancy developed a method known as the Indicators of Hydrological... -
River and wetland classifications for freshwater conservation planning in KwaZulu-Natal, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: NA Rivers-Moore --- Ezemvelo KZN Wildlife, South Africa PS Goodman --- Ezemvelo KZN Wildlife, South AfricaTo provide the foundation for a freshwater conservation plan for KwaZulu-Natal, three-level hierarchical river and wetland type classifications, based on spatio-temporal scaling relationships, are proposed. This resolution of classification is appropriate for regional- or provincial-scale conservation planning. The hierarchical structure... -
Composition, abundance, distribution and seasonality of zooplankton in the Sundays Estuary, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: K Sutherland --- Department of Zoology, South Africa TH Wooldridge --- Department of Zoology, South Africa NA Strydom --- Department of Zoology, South AfricaThe zooplankton assemblage in the permanently open Sundays Estuary, on the south-east coast of South Africa, was studied seasonally. Samples were collected once per season between winter 2007 and autumn 2009 by means of boat-based plankton tows. A total of... -
Treatment Effects on Annual and Dry Period Streamflow at Cathedral Peak
Item type: Journal Article • Journal: South African Forestry Journal • Authors: J.M. Bosch --- Department of Forestry,Total annual streamflow and dry season flows of treated catchments at Cathedral Peak, Natal, were compared and related to those of index catchments. -
An Integrated System for Forest Management and Silvicultural Planning and Control in South African State Forestry
Item type: Journal Article • Journal: South African Forestry Journal • Authors: H.W. Kassier --- Forest Management Division, Department of Water Affairs, Forestry and Environmental Conservation,A computerised plantation analysis system (COMPAS) for commercial plantation management, planning and control is described and illustrated. Present uses in South African State forestry and future development of the system are discussed. -
Overland Flow on Small Plots at the Jonkershoek Forestry Research Station
Item type: Journal Article • Journal: South African Forestry Journal • Authors: D.B. Versfeld --- Department of Environment Affairs,Overland flow was found to be negligible on small plots at Jonkershoek in the Western Cape. Treatments such as the burning or hoeing of fynbos and the thinning of a plantation had no significant effect on this phenomenon and the... -
Could phosphorus concentrations increase with the development of cage culture in Lake Kariba, Zimbabwe?
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: L Mhlanga --- Department of Biological Sciences, Zimbabwe W Mhlanga --- Department of Environmental Science, Zimbabwe P Mwera --- Lake Harvest, Zimbabwe P Tendaupenyu --- Department of Biological Sciences, ZimbabweA comparison between historical and current data was done to determine whether the concentrations of total phosphorus, orthophosphate and chlorophyll a, and Secchi disc transparency, have changed in the Sanyati Basin of Lake Kariba following the commencement of cage culture... -
FUTURE CHALLENGES IN WATER QUALITY MODELLING WITH PARTICULAR REFERENCE TO OPERATIONALLY CLOSED CATCHMENTS
Item type: Journal Article • Journal: Southern African Journal of Child and Adolescent Mental Health • Authors: S.F. Forster --- Department of Water Affairs, South Africa F.A. Stoffberg --- Department of Water Affairs, South Africa J.A. van Rooyen --- Department of Water Affairs, South AfricaAs a result of the declining quality of many water sources, the use of water quality models in planning is increasing. To date applications have involved the simulation of total dissolved salts and nutrients, largely in catchments affected by urban... -
Characteristics and value of the Thukela Banks crustacean and linefish fisheries, and the potential impacts of changes in river flow
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JK Turpie --- Anchor Environmental Consultants, South Africa SJ Lamberth --- Branch Fisheries, Department of Agriculture, Forestry and Fisheries, South AfricaThis study describes the Thukela Banks crustacean and linefish fisheries and investigates the potential impacts of reduced flow from the Thukela River on the value of these fisheries. Data were obtained from published and unpublished material, key informants and government... -
A Parametric Study of a Natural Flow Solar Air Heater with a Rectangular Air-Duct Profile
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: H. O. Ondieki [d858022e20] J. K. TonuiThis article presents a theoretical analysis of a solar air heater (SAH) with a rectangular air duct profile operated in a natural airflow mode. The study involves modelling the SAH system and simulated results are used to study the effects... -
A new approach to modelling streamflow reductions resulting from commercial afforestation in South Africa
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: M.B. Gush --- Environmentek CSIR, D.F. Scott --- Department of Earth and Environmental Sciences, Canada G.P.W. Jewitt --- School of Bio-Resources Engineering and Environmental Hydrology, R.E. Schulze --- School of Bio-Resources Engineering and Environmental Hydrology, L.A. Hallowes --- , A.H.M. Görgens --- Dept. of Civil Engineering,The Department of Water Mfairs and Forestry has, for some time, needed a comprehensive tool to incorporate the impacts of commercial afforestation on water resources into water use authorisation and allocation processes. Simulation modelling on a national scale, using the... -
Modelling maximum canopy conductance and transpiration in Eucalyptus grandis stands not subjected to soil water deficits
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: J. M. Campion --- , Republic of South Africa P.J. Dye --- Environmentek, CSIR, c/o Agrometeorology, Republic of South Africa M.C. Scholes --- School of Animal, Plant and Environmental Sciences, Republic of South AfricaThere is much current interest in predicting the maximum amount of water that can be transpired by Eucalyptus trees. It is possible that industrial waste water may be applied as irrigation water to eucalypts and it is important to predict... -
Confirmation of cytotype stability in autotetraploid black wattle (Acacia mearnsii) trees using flow cytometry and size differences of the reproductive gametes
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: SaschaL Beck-Pay --- , South AfricaAcacia mearnsii (black wattle) is grown commercially in South Africa for its timber and bark. However, the invasive nature of the species has resulted in it being considered an alien invader and for this reason research has been aimed at... -
Amplified Fragment Length Polymorphism markers reveal population structuring in Dimidiochromis kiwinge (Teleostei: Cichlidae), a commercially-exploited species from Lake Malawi
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Daud Kassam Shingo Seki Kosaku YamaokaThe understanding of between- and within-population genetic variation and its partitioning on the basis of geographic origin is crucial in designing efficient fishing and conservation strategies of populations and/or species. However, for Lake Malawi's cichlid species, such population genetic studies... -
Impact of winter flow regulation on pest-level populations of blackfly (Diptera: Simuliidae) and non-target faunal communities in a South African river
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: NA Rivers-Moore FC de MoorThe mid-reaches of the Great Fish River in the Eastern Cape Province of South Africa experience regular outbreaks of the pest blackfly Simulium chutteri as a direct consequence of increased flows caused by an inter-basin transfer scheme. There are opportunities... -
Changes in the trophic structure of the southern Benguela before and after the onset of industrial fishing
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: KE Watermeyer LJ Shannon CL GriffithsDespite a human presence in the Benguela region for at least one million years, exploitation of marine resources by European seafarers only began in earnest in the 1400s. Ecopath with Ecosim was used to construct and compare mass-balanced foodweb models... -
Changes in the trophic structure of the northern Benguela before and after the onset of industrial fishing
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: KE Watermeyer LJ Shannon J-P Roux CL GriffithsExploitation of marine resources has been occurring in the northern Benguela ecosystem for centuries. Understanding the cumulative long-term effects of this exploitation is important toward effective management of the modern system. Retrospective mass-balanced models of the ecosystem have been constructed,... -
Comparison of, and the effects of altered freshwater inflow on, fish assemblages of two contrasting South African estuaries: the cool-temperate Olifants and the warm-temperate Breede
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SJ Lamberth L van Niekerk K HutchingsThis study compares the fish assemblages of the permanently open cool-temperate Olifants and warm-temperate Breede estuaries on the west and south coasts of South Africa respectively, and their responses to altered freshwater flows. Both estuaries have experienced a >35% reduction... -
A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AK Whitfield JB Adams GC Bate K Bezuidenhout TG Bornman PD Cowley PW Froneman PT Gama NC James B Mackenzie T Riddin GC Snow NA Strydom S Taljaard AI Terörde AK Theron JK Turpie L van Niekerk PD Vorwerk TH WooldridgeIn 2005/2006 a multidisciplinary research programme that included studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fish and birds of the temporarily open/closed East Kleinemonde Estuary was conducted. Particular attention was given to the responses... -
High genetic homogeneity of the moon jelly Aurelia aurita (Scyphozoa, Semaeostomeae) along the Mediterranean coast of Tunisia
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AR Ben Faleh A Ben Othmen T Deli A Annabi K SaidThe moon jelly Aurelia aurita is one of the most common and widespread species of scyphomedusa in the Mediterranean Sea. In all, 18 allozyme loci were studied to investigate the genetic variation and population structure of 11 A. aurita populations... -
Why do we need to integrate population genetics into South African marine protected area planning?
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: S von der Heyden --- Evolutionary Genomics Group, Department of Botany and Zoology, South AfricaSouth Africa is home to a wide variety of marine flora and fauna distributed over at least three biogeo-graphic provinces. Currently, 9% of the coastline is protected by ‘no-take’ marine protected areas (MPAs), but the distribution of MPAs is uneven... -
Reproductive biology of Corymbia citriodora subsp. variegata and effective pollination across its native range in Queensland, Australia
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: CFE Bacles J Brooks DJ Lee PM Schenk AJ Lowe A KremerThe spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora subsp... -
The effect of bacterial-based biofertilisers and cytokinin on the emergence of sunflower at non-limiting and supra-optimal temperatures
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Andries A Nel --- Agricultural Research Council–Grain Crops Institute, South AfricaSubsurface sunflower (Helianthus annuus L.) seedling growth often deteriorates on sandy-textured soils due to supra-optimal temperature levels on the Highveld area of South Africa leading to poor emergence and suboptimum plant population densities. It has been shown that seedling growth... -
Unravelling population structure of black musselcracker Cymatoceps nasutus: evidence for multiple populations in South African coastal waters
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: TS Murray --- Department of Ichthyology and Fisheries Science, South Africa G Gouws --- South African Institute for Aquatic Biodiversity, South Africa M Mwale --- South African Institute for Aquatic Biodiversity, South Africa BQ Mann --- Oceanographic Research Institute, South Africa PD Cowley --- South African Institute for Aquatic Biodiversity, South AfricaGenetic studies on South African marine fishes have shown that many species exist as single, well-mixed stocks throughout their core distribution. The black musselcracker or poenskop Cymatoceps nasutus is a slow-growing, late-maturing and long-lived sparid (Perciformes: Sparidae) that is endemic... -
Seasonal pattern of chytridiomycosis in common river frog (Amietia angolensis ) tadpoles in the South African Grassland Biome
Item type: Journal Article • Journal: African Zoology • Authors: Werner Conradie --- Department of Herpetology, South Africa Ché Weldon --- Unit for Environmental Research: Zoology, North-West University, South Africa Kevin G. Smith --- Tyson Research Centre, Washington University in St. Louis, U.S.A. Louis H. Du Preez --- Unit for Environmental Research: Zoology, North-West University, South AfricaEnvironmental parameters such as temperature and rainfall influence the biology of amphibians and are likely to similarly influence the growth and prevalence of associated pathogens. Amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), causes an infectious disease, chytridiomycosis, in amphibians worldwide. Field... -
Integrating research with management: the case of Katavi National Park, Tanzania
Item type: Journal Article • Journal: African Zoology • Authors: T. Caro --- Department of Wildlife, Fish and Conservation Biology, U.S.A. M. Elisa --- Katavi National Park, Tanzania J. Gara --- Katavi National Park, Tanzania D. Kadomo --- Katavi National Park, Tanzania A. Martin --- Department of Wildlife, Fish and Conservation Biology, U.S.A. D. Mushi --- Katavi National Park, Tanzania C. Timbuka --- Katavi National Park, TanzaniaMany protected areas in Africa and elsewhere suffer from several external pressures making it difficult for management to set priorities. For example, aerial censuses show that many mammal populations in the Katavi-Rukwa ecosystem of western Tanzania are declining. Vehicle transect... -
Historical demography of southern African patellid limpets: congruence of population expansions, but not phylogeography
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: KL Mmonwa --- SANBI Marine Programme, South Africa PR Teske --- Department of Zoology, South Africa CD McQuaid --- Coastal Research Group, Department of Zoology and Entomology, South Africa NP Barker --- Molecular Ecology and Systematics Group, Department of Botany, South AfricaGlobal climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum... -
Reproductive biology of the critically endangered tropical tree Talbotiella gentii
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Daniel Dompreh --- Department of Plant and Soil Science, UK Michael D Swaine --- Department of Plant and Soil Science, UK Christopher C Wilcock --- Department of Plant and Soil Science, UKTalbotiella gentii is a critically endangered caesalpiniaceous legume endemic to Ghana, restricted in distribution to the margins of the forest zone where there has been extensive fire damage in recent decades. It occurs as isolated, near-monospecific populations, some of which... -
A tool for identifying potential Eucalyptus nitens seed orchard sites based on climate and topography
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Ilaria Germishuizen --- Institute for Commercial Forestry Research, South Africa Robin AW Gardner --- Institute for Commercial Forestry Research, South AfricaShy seed production in orchards of Eucalyptus nitens is a major barrier to the deployment of genetic gain in South African plantations. A machine learning method was used to identify optimal sites for the establishment of E. nitens seed orchards... -
On the distributions of cash flow ratios of listed South African industrial companies
Item type: Journal Article • Journal: South African Journal of Accounting Research • Authors: W D Hamman --- Graduate School of Business, E V d M Smit --- Graduate School of Business, A C Jordaan --- Graduate School of Business,This paper investigates the assumption of normality in the distribution of cash flow ratios of listed South African industrial companies over the period 1974 to 1993. Twenty eight cash flow ratios are defined and the distributions are investigated for the... -
The value relevance of earnings, operating cash flow and accruals: A study on UK data
Item type: Journal Article • Journal: South African Journal of Accounting Research • Authors: N Garrod --- Law and Management, Republic of South Africa B Giner --- University of Valencia, Spain M Larrán --- University of Cadiz, SpainThe purpose of the work reported in this paper is to establish the value relevance of earnings, operating cash flows and accruals for UK companies. Innovations in this paper are threefold: the use of a valuation rather than a returns... -
The time series behaviour of net profit, cash flow from operating activities and accruals of South African listed industrial companies for the period December 1988 to November 2002
Item type: Journal Article • Journal: South African Journal of Accounting Research • Authors: B W Steyn --- Department of Accountancy, W D Hamman --- Graduate School of Business,Harmonising South African accounting methods with international trends led to basically all South African accounting statements being revised after December 1994. This resulted in changes in accounting policies and methods and, quite often, involved more conservative requirements than previously. -
Capital budgeting: A case study analysis of the role of formal evaluation techniques in the decision making process
Item type: Journal Article • Journal: South African Journal of Accounting Research • Authors: E Gilbert --- Graduate School of Business, University of Cape Town,This paper furthers the understanding of capital budgeting by reviewing two individual capital investment decisions taken by manufacturing firms in South Africa. This study indicates that managers do not base their capital investment decisions on a comparison of the expected... -
Basic Financial Statements: Objectives, Categories, Principles and Presentation
Item type: Journal Article • Journal: De Ratione • Authors: J.A. Miller --- University of Natal,Objectives ae suggested for each of the basic financial statements in the annual report of a business entity. Categories of information required and the principles used in their classification, are identified and defined. A suggested presentation reflects cash flow alongside... -
Reforming taxation of business for rationalisation and inflation-neutrality
Item type: Journal Article • Journal: De Ratione • Authors: Wesley J Gavin --- Professor in the Department of Accounting at Rhodes University,Taxation of business in South Africa needs reforming to avoid inflationary distortions and investment disincentives. Inflation adjusted income has largely been abandoned as a feasible tax base. Taxing both corporate and non-corporate business income at a flat rate on the... -
Production potential of Italian and Westerwolds ryegrass established at different planting dates
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Philip R Botha --- Western Cape Department of Agriculture, Outeniqua Research Farm, South Africa Lethu B Zulu --- Western Cape Department of Agriculture, Outeniqua Research Farm, South Africa Janke van der Colf --- Western Cape Department of Agriculture, Outeniqua Research Farm, South Africa Pieter A Swanepoel --- Department of Agronomy, South AfricaFodder flow planning is essential for dairy-pasture systems because its implementation allows fodder to be available throughout the year. Italian and Westerwolds ryegrass varieties (Lolium multiflorum var. italicum and westerwoldicum, respectively) are temperate annuals often planted in the southern Cape... -
The dimensionality of the Work Related Flow Inventory (WOLF): a South African study
Item type: Journal Article • Journal: Journal of Psychology in Africa • Authors: Ita Geyser --- School of Tourism and Hospitality Management, South Africa Madelyn Geldenhuys --- Industrial Psychology and People Management, South Africa Freddie Crous --- Industrial Psychology and People Management, South AfricaThe objective of this study was to validate and explore the factor structure of the Work-Related Flow Inventory (WOLF) as a measure of flow within the South African work context. The sample consisted of N = 415 employees from various organisations in... -
Effect of heat stress on seed yield components and oil composition in high- and mid-oleic sunflower hybrids
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Rouxléne van der Merwe --- Department of Plant Sciences, South Africa Maryke T Labuschagne --- Department of Plant Sciences, South Africa Liezel Herselman --- Department of Plant Sciences, South Africa Arno Hugo --- Department of Microbial, Biochemical and Food Biotechnology, South AfricaHigh temperature stress is a major environmental factor influencing processes such as growth, yield and quality of crops. The objective of this study was to assess the effect of heat stress, applied during grain-filling, on seed yield- and oil quality... -
What factors drive fishery yields in the Lower Shire River, Malawi?
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D Tweddle --- South African Institute for Aquatic Biodiversity, South AfricaThe Shire River drains from Lake Malawi to the Lower Zambezi River. Annual flow is dependent mainly on lake level, partially controlled by the operation of a barrage at Liwonde to regulate flows for hydroelectricity generation in the escarpment reaches... -
The case for environmental flow determination for the Phongolo River, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: T Dube --- Laboratory of Aquatic Ecology, Evolution and Conservation, Belgium V Wepener --- Research Unit for Environmental Sciences and Management, South Africa JHJ van Vuren --- Department of Zoology, South Africa N Smit --- Research Unit for Environmental Sciences and Management, South Africa L Brendonck --- Laboratory of Aquatic Ecology, Evolution and Conservation, BelgiumThe construction of Pongolapoort Dam in 1973 on the Phongolo River in KwaZulu-Natal, South Africa, has considerably altered the hydrological behaviour and ecological response of the downstream floodplain. Changes in the flooding regime have had implications for the socio-economic importance... -
Global and African: exploring hip-hop artists in Philippi Township, Cape Town
Item type: Journal Article • Journal: Anthropology Southern Africa • Authors: Heike Becker --- Dept of Anthropology & Sociology, Nceba Dastile --- Dept of Anthropology & Sociology,This article investigates hip-hop, identity and global cultural flows among young people in contemporary Cape Town. We argue that hip-hop functions as a vehicle for identity negotiations in contemporary South Africa. The discussion of hip-hop in an ‘African’ township shows... -
Movement behaviour of largemouth bass Micropterus salmoides in a South African impoundment
Item type: Journal Article • Journal: African Zoology • Authors: Dylan H Howell --- Department of Ichthyology and Fisheries Science, South Africa Paul D Cowley --- Department of Ichthyology and Fisheries Science, South Africa Amber-Robyn Childs --- Department of Ichthyology and Fisheries Science, South Africa Olaf LF Weyl --- Department of Ichthyology and Fisheries Science, South AfricaThe objectives of this study were to describe movements and area use patterns of largemouth bass Micropterus salmoides in relation to abiotic factors (water temperature, river inflow and water level). The study was conducted in the Kubusi arm of Wriggleswade... -
The routine paediatric human immunodeficiency virus visit as an intervention opportunity for failed maternal care, and use of point-of-care CD4 testing as an adjunct in determining antiretroviral therapy eligibility
Item type: Journal Article • Journal: Southern African Journal of Infectious Diseases • Authors: S C Picken --- HOPE Cape Town Association and Trust, Faculty of Medicine and Health Sciences, Stellenbosch University, S Williams --- HOPE Cape Town Association and Trust, Faculty of Medicine and Health Sciences, Stellenbosch University, J Harvey --- Centre for Statistical Consultation, Stellenbosch University, M M Esser --- Head of Immunology Unit, NHLS Tygerberg Division of Medical Microbiology, Department of Pathology, Stellenbosch University,South African women and children remain at the centre of the human immunodeficiency virus (HIV) pandemic, and maternal well-being plays a critical role in child health. In this study, we evaluated the impact of the paediatric visit on the determination... -
Skull morphometrics of male Subantarctic fur seals (Arctocephalus tropicalis) from Marion and Gough Islands
Item type: Journal Article • Journal: African Zoology • Authors: Graham I.H. Kerley --- Zoology Department, South Africa Bryce R. Allen --- Zoology Department, South Africa Marthán N. Bester --- Department of Zoology and Entomology, South AfricaSkull morphometrics of two populations of Subantarctic fur seal (Arctocephalus tropicalis) were compared in order to identify possible geographic variation as an indicator of gene flow between the populations, as well as a potential tool to identify the source of... -
The role of teammate relationships, communication and self-efficacy in predicting athlete flow experience
Item type: Journal Article • Journal: Journal of Psychology in Africa • Authors: Frederick W. Stander --- Optentia Research Focus Area, South Africa Sebastiaan Rothmann --- Optentia Research Focus Area, South Africa Elrie Botha --- Optentia Research Focus Area, South AfricaThis study aimed at testing a structural model of athlete flow in a sample of South African students. A quantitative, cross-sectional research design was implemented. Participants completed self-report measures at pre-arranged times that were in close proximity to the completion... -
Influence of the annual flood-pulse on catch per unit effort, condition and reproduction of Clarias gariepinus from the upper Okavango Delta, Botswana
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: T Bokhutlo --- Department of Biology and Biotechnological Sciences, Botswana OLF Weyl --- South African Institute for Aquatic Biodiversity, South Africa K Mosepele --- Okavango Research Institute (University of Botswana), Botswana GG Wilson --- Ecosystem Management, School of Environmental and Rural Science, AustraliaCatch per unit effort (CPUE), length, weight and maturity data for Clarias gariepinus were collected during monthly gillnet surveys in the upper Okavango Delta between 2001 and 2009 to investigate their relationship with the annual flood-pulse. CPUE, condition factor (K)... -
Monitoring eucalypt bud temperature using mobile temperature loggers
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Robin AW Gardner --- Institute for Commercial Forestry Research, South Africa Michael J Savage --- Agrometeorology Discipline, School of Agricultural, Earth and Environmental Sciences, South Africa Isa Bertling --- Horticultural Science Discipline, School of Agricultural, Earth and Environmental Sciences, South AfricaWinter chilling is a key environmental trigger of floral induction in temperate Eucalyptus. Over the past two decades, considerable site × eucalypt flowering interaction research has been undertaken over a range of high elevation (>1 100 m asl) forestry sites in... -
Common-wide information flow in CDS markets: The case of earnings surprises of industry leaders
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Paulo Pereira da Silva --- CMVM-Portuguese Securities Commission, Rua Laura Alves n.° 4, Lisbon, PortugalThis paper examines the way common-wide information is disseminated in credit default swap (CDS) markets. I find strong supporting evidence that earnings announcements of CDS references with greater liquidity and higher credit risk help in predicting the subsequent CDS spread... -
South African seed oils are safe for human consumption
Item type: Journal Article • Journal: South African Journal of Clinical Nutrition • Authors: M Opperman --- Functional Foods Research Unit, Department of Biotechnology and Consumer Science, AJS Benadé --- Functional Foods Research Unit, Department of Biotechnology and Consumer Science, CF Abrecht --- Cancer Association of South Africa, LL Matsheka --- Functional Foods Research Unit, Department of Biotechnology and Consumer Science,Objectives: A diet that is high in fat and low in carbohydrates is advocated in the recently published The Real Meal Revolution. A suggestion was made in this publication that seed oils are toxic. The authors stated that available seed... -
A system-level modelling perspective of the KwaZulu-Natal Bight ecosystem, eastern South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: UM Scharler --- School of Life Sciences, South Africa RC van Ballegooyen --- Coastal Systems Research Group, South Africa MJ Ayers --- School of Life Sciences, South AfricaThe KwaZulu-Natal Bight comprises the only sizeable shelf region on the eastern coast of South Africa, and is influenced by both the Agulhas Current on its seaward side and rivers and estuaries on its landward side. Established knowledge of the... -
The annual pattern of sap flow in two Eucalyptus species established in the vicinity of gold-mine tailings dams in central South Africa
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Peter Dye --- Ecological Engineering and Phytotechnology Programme, Restoration and Conservation Biology Research Group, School of Animal, Plant and Environmental Sciences, South Africa Alistair Clulow --- Agrometeorology, South Africa Eric Prinsloo --- CSIR, Built Environment, South Africa Vivek Naiken --- CSIR, Natural Resources and the Environment, c/o Agrometeorology, South Africa Isabel Weiersbye --- Ecological Engineering and Phytotechnology Programme, Restoration and Conservation Biology Research Group, School of Animal, Plant and Environmental Sciences, South AfricaSeveral hundred mine tailings dams occur in the Witwatersrand Basin Goldfields in central South Africa. Seepage of acid mine drainage (AMD) from these unlined structures is widespread, and a variety of contaminants is released into soil and groundwater. The ‘Mine... -
Effect of conservation agriculture associated crop rotation systems on root and crown rot severity and respective soil-borne pathogens of maize (Zea mays L.) in the Highveld area of South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Maryke Craven --- Agricultural Research Council – Grain Crops Institute, South Africa André A Nel --- Agricultural Research Council – Grain Crops Institute, South AfricaAlthough crop rotation reduces the incidence of soil-borne diseases, reduced tillage practices create the risk of increased disease incidence. Monoculture maize (MM) under both conventional tillage (CT) and conservation agriculture (CA) crop systems were evaluated against two-and three-year rotation CA... -
Emergence response of sunflower (Helianthus annuus) cultivars to supra-optimal soil temperatures
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Lize Henning --- Department of Soil, Crop and Climate Sciences, South Africa Gert Ceronio --- Department of Soil, Crop and Climate Sciences, South Africa André A Nel --- Agricultural Research Council–Grain Crops Institute, South AfricaSeedling emergence is a sensitive stage during sunflower (Helianthus annuus L.) establishment. Abiotic stresses, such as high soil temperatures (above 40 °C), can cause delayed emergence resulting in uneven stand and ultimately poor yields. Therefore, the emergence and early growth... -
Growth and phenology of a three- to four-year-old Sclerocarya birrea international provenance trial in Malawi
Item type: Journal Article • Journal: Southern Hemisphere Forestry Journal • Authors: PW Chirwa RJ Bwanali G Meke W Sagona CRY Munthali L MwabumbaIndigenous wild fruits of Sclerocarya birrea have been used to supplement diets in time of critical food shortage, generate income when sold and as a source of raw materials for natural food-based industries in many developing countries. However, the widespread... -
Domestic Resource Mobilization in Africa: State, Capacity Imperatives and Policy Actions
Item type: Journal Article • Journal: Africa Journal of Management • Authors: Emmanuel Nnadozie --- The African Capacity Building Foundation, Zimbabwe Thomas Munthali --- The African Capacity Building Foundation, Zimbabwe Robert Nantchouang --- The African Capacity Building Foundation, Zimbabwe Barassou Diawara --- The African Capacity Building Foundation, ZimbabweIn Agenda 2063 and Agenda 2030, Africa has its major development aspirations defined in the broader global and continental economic development context. Implementation of the two Agendas calls for substantial financial resources at a time when the global development finance... -
Fish recruitment into a South African temporarily open/closed temperate estuary during three different hydrological mouth phases
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GP Tweddle --- Department of Zoology, South Africa PW Froneman --- Department of Zoology and Entomology, South AfricaQuantitative recruitment of ichthyofauna into a South African temporarily open/closed estuary (TOCE) was investigated during three distinct hydrological phases: closed overwash, open outflow and tidal mouth conditions. Maximum recruitment densities occurred during outflow conditions and declined when the system became... -
The potential of Vachellia kosiensis (Acacia kosiensis) as a dryland forestry species in terms of its water use, growth rates and resultant water-use efficiency
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Mark B Gush --- CSIR Natural Resources and the Environment, South AfricaThe potential of the country’s numerous indigenous tree species to address challenges facing the commercial forestry industry in South Africa is under-explored. Relevant issues include the rising demand for timber and non-timber forest products due to population and economic growth,... -
Do mutual fund flows drive the disposition behaviour of fund managers?
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Min-Hsien Chiang --- Institute of International Business, Taiwan Hsin-Yi Huang --- Department of Finance, TaiwanThis study examines the relationship between fund flows and the disposition behaviour of fund managers. During our sample period of 1996–2014, we find that the disposition biases of fund managers are significantly and negatively correlated with unexpected fund flows but... -
Genetic structure of wild and domesticated grasscutters (Thryonomys swinderianus) from south-western Nigeria
Item type: Journal Article • Journal: African Zoology • Authors: Oluwakayode M Coker --- Department of Wildlife and Ecotourism Management, Nigeria Abosede O Omonona --- Department of Wildlife and Ecotourism Management, Nigeria Olusegun A Fagbohun --- Department of Veterinary Microbiology and Parasitology, Nigeria Cortney Pylant --- Department of Wildlife Ecology and Conservation, USA James D Austin --- Department of Wildlife Ecology and Conservation, USAGrasscutter (Thryonomys swinderianus) is a large rodent distributed across sub-Saharan Africa that is highly valued as a source of protein. There has been little effort to evaluate the genetic structure of grasscutters despite long-term harvesting pressure and over 40 years... -
A South African softwood sawtimber supply chain case study
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Pierre A Ackerman --- Department of Forest and Wood Science, South Africa Elizabeth A van der Merwe --- Department of Forest and Wood Science, South Africa Reino E Pulkki --- Department of Forest and Wood Science, South AfricaSupply chain management principles were analysed by investigating the effects of smaller-scale and incremental interventions in a forest-to-mill value chain on financial returns and forest resource use in an Eastern Cape case study area. Three previous studies provided input by... -
The impact of river flooding and high flow on the demersal fish assemblages of the freshwater-dominated Great Fish Estuary, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: P Nodo --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa NC James --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa A-R Childs --- Department of Ichthyology and Fisheries Science, South Africa MDV Nakin --- Department of Biological and Environmental Sciences, South AfricaFreshwater inflow has a strong impact on the biological, chemical and physical characteristics of estuaries, which in turn affect the distribution and abundance of estuarine organisms. Increased climatic variability associated with climate change is predicated to modify precipitation patterns, which... -
Single-tree water use and water-use efficiencies of selected indigenous and introduced species in the Southern Cape region of South Africa
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Tatenda Mapeto --- School of Natural Resources Management, South Africa Mark Gush --- CSIR, Natural Resources and Environment, South Africa Josua Louw --- School of Natural Resources Management, South AfricaIn South Africa, the development of a plantation tree industry using fast-growing introduced species was accelerated by the limited extent of indigenous forests. However, concerns about the impacts of plantations on the country’s limited water resources has initiated forest hydrology... -
Inventive activity and knowledge flows in the Mediterranean area: A social network analysis based investigation approach
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Massimiliano Ferrara --- Mediterranean University of Reggio Calabria, Italy Roberto Mavilia --- University for Foreigners ‘Dante Alighieri’, MEDAlics, Via del Torrione 95, Italy Francesca Larosa --- University for Foreigners ‘Dante Alighieri’, MEDAlics, Via del Torrione 95, ItalyThis paper investigates the collaboration of inventive activities at firm level in the Mediterranean area by investigating, through social network analysis, the collaboration between the two shores of Mediterranean area. Using patent data, our aim is to capture some relevant... -
The winner takes it all: Outperformance drives subsequent flows in South African Unit Trust Funds
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Jennifer Arendse --- Gordon Institute of Business Science, South Africa Chris Muller --- Gordon Institute of Business Science, South Africa Michael Ward --- Gordon Institute of Business Science, South AfricaThe relationship between unit trust (mutual fund) performance and subsequent investment flows into and out of funds has been the focus of many international studies. Emerging markets, which are characterised by higher risk, weaker institutions, volatile economies and fewer participants,... -
Alternative method for the identification of critical nodes leading to voltage instability in a power system
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Isaiah G. Adebayo --- Department of Electrical Engineering, South Africa Adisa A. Jimoh --- Department of Electrical Engineering, South Africa Adedayo A. Yusuff --- Department of Electrical and Mining Engineering, South Africa Yanxia Sun --- Department of Electrical and Electronic Engineering Science, South AfricaThe introduction of new operation enhancement technologies plus increasing application of power electronics, coupled with the continuous increase in load demand, has increased the risk of power networks to voltage instability and susceptibility to voltage collapse. This frequent occurrence of... -
Genetic diversity and population connectivity of the sea urchin Tripneustes gratilla along the South African coast
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: M Brink --- Molecular Breeding and Biodiversity Group, Department of Genetics, South Africa R Dale Kuys --- Molecular Breeding and Biodiversity Group, Department of Genetics, South Africa C Rhode --- Molecular Breeding and Biodiversity Group, Department of Genetics, South Africa BM Macey --- Branch: Fisheries Management, Department of Agriculture, South Africa KW Christison --- Branch: Fisheries Management, Department of Agriculture, South Africa R Roodt-Wilding --- Molecular Breeding and Biodiversity Group, Department of Genetics, South AfricaThe collector sea urchin Tripneustes gratilla has been identified as a species with potential for aquaculture production in South Africa. The species’ roe is considered a culinary delicacy in Asia and Europe. However, T. gratilla remains genetically uncharacterised in South... -
Liquidity and the convergence to market efficiency
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Nicara Young --- School of Economic and Business Sciences, South Africa Christo Auret --- School of Economic and Business Sciences, South AfricaThe aim of this study is to investigate the relationship between market liquidity changes on the Johannesburg Stock Exchange (JSE) and the market’s degree of efficiency. Market efficiency is characterised in terms of two philosophies: Fama’s (1970) Efficient Markets Hypothesis... -
Relationships of water temperature and aquatic macroinvertebrate community structure with non-native riparian plant densities in the southern Cape, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: NA Rivers-Moore --- Centre for Water Resources Research, South Africa HF Dallas --- Freshwater Research Centre, South Africa, and Nelson Mandela Metropolitan University, South Africa FC de Moor --- Albany Museum and Department of Zoology and Entomology, South Africa J Barendse --- Sustainability Research Unit/South African National Parks, South AfricaNon-native vegetation in the riparian zone impacts on water temperatures, flow patterns, degree of shading, channel modification, and changes to natural sediment loads. Freshwater ecosystems in the Garden Route Initiative planning domain are of particular conservation value, because of the... -
Whole-tree sap flow responses to soil water and weather variables for Pinus radiata and three indigenous species in a southern afrotemperate forest region
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Tatenda Mapeto --- School of Natural Resources Management, Nelson Mandela University, George Campus, South Africa Josua Louw --- School of Natural Resources Management, Nelson Mandela University, George Campus, South Africa Mark Gush --- Council for Scientific and Industrial Research, South Africa Jeanette Pauw --- School of Natural Resources Management, Nelson Mandela University, George Campus, South AfricaIn a water-scarce country such as South Africa, timber and fibre production often stands in conflict with catchment water yields. The optimal provision of both is sought. Forest hydrological experiments improve our understanding of the soil–plant–atmosphere continuum and facilitate the... -
Inoculum availability and infection patterns of Fusarium mangiferae, the causal agent of mango malformation in South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Maritha H Schoeman --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa Ncobile B Zulu --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa F André Botha --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa Frikkie J Calitz --- Agricultural Research Council–Biometry, South AfricaMango malformation, caused by Fusarium mangiferae, is a serious disease of mango in South Africa, causing severe economic losses annually. The occurrence of conidia of F. mangiferae on malformed inflorescences and leaves and the timing of airborne infections were studied... -
Greenhouse evaluation of Trichoderma harzianum for the control of Sclerotinia wilt (Sclerotinia sclerotiorum) of sunflower
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: James R Mathews --- Discipline of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, College of Agriculture and Environmental Sciences, South Africa Benice J Sivparsad --- Discipline of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, College of Agriculture and Environmental Sciences, South Africa Mark D Laing --- Discipline of Plant Pathology, School of Agriculture, Earth and Environmental Sciences, College of Agriculture and Environmental Sciences, South AfricaSclerotinia sclerotiorum, the causal organism of Sclerotinia wilt, is an economically important disease affecting sunflower in South Africa. The goal of this investigation was to evaluate the potential of a strain of Trichoderma harzianum, T77, for control of S. sclerotiorum... -
Integrated control of mango blossom malformation in South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Magaritha H Schoeman --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa Ncobile B Zulu --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa F André Botha --- Agricultural Research Council–Tropical and Subtropical Crops, South Africa Frikkie J Calitz --- Agricultural Research Council–Biometry, South AfricaMango malformation disease (MMD) is a serious disease worldwide, causing severe economic losses annually. In South Africa, recommendations for managing MMD are to break out malformed inflorescences when clearly visible. Despite these recommendations, high incidences of MMD were reported during... -
Financial Profitability of Carbon Offset Monoculture Plantation Forestry on Smallholder Farms in Trans Mara Sub-County, Kenya
Item type: Journal Article • Journal: East African Agricultural and Forestry Journal • Authors: J. Chemuliti --- Kenya Agricultural and Livestock Research Organization, Kenya C. Ackello-Ogutu --- Department of Agricultural Economics, Kenya S. Mbogoh --- Department of Agricultural Economics, Kenya P. Irungu --- Department of Agricultural Economics, KenyaThere is growing interest in the development of smallholder carbon offset forestry projects in Africa as a means of mitigating climate change while providing co-benefits of development and environmental protection and conservation. Financial profitability of carbon projects is a key... -
Assessment of consumer preference traits of indigenous sheep type and market channels in Bensa District, Southern Ethiopia
Item type: Journal Article • Journal: East African Agricultural and Forestry Journal • Authors: H Kenfo --- Southern Agricultural Research Institute, Ethiopia Y Mekasha --- International Livestock Research Institute, Ethiopia Y Tadesse --- Haramaya University, EthiopiaThis study was carried out in Bensa district of Sidama Zone, southern Ethiopia. The objective of this study was to assess consumer preference traits of indigenous sheep type in the study area. Data were analysed using SPSS versions 16. There... -
Incidence and Severity of Common Bean (Phaseolus vulgaris L.) Pests in Agro-Ecological Zones and Farming Systems of Western Kenya
Item type: Journal Article • Journal: East African Agricultural and Forestry Journal • Authors: JO Ogecha --- Kenya Agricultural and Livestock Research Organization, Kenya W Arinaitwe --- International Centre for Tropical Agriculture, Kampala Uganda JW Muthomi --- Department of Crop Protection, Kenya V Aritua --- International Centre for Tropical Agriculture, Kampala Uganda JN Obanyi --- Kenya Agricultural and Livestock Research Organization, KenyaInfestation by insect pests is a serious problem in legume up scaling activities and a threat to future production in Kenya. The survey aimed at determining incidence and severity of insect pests of common beans in different districts and agro-ecological... -
Design, fabrication and performance evaluation of centrifugal sunflower dehuller for small-scale enterprises in developing countries
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Yuda Lyangalo Benjamin --- Department of Engineering Sciences and Technology, Tanzania Ezra Lazaro --- Department of Engineering Sciences and Technology, TanzaniaSunflower is grown by small-scale farmers in many developing countries like Tanzania. Lack of effective machines for dehulling sunflower seeds has resulted in high oil losses during extraction, especially for small- and medium-scale enterprise. This paper reports on the design,... -
Performance comparison between genetic programming and sediment rating curve for suspended sediment prediction
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Adesoji Tunbosun Jaiyeola --- Faculty of Engineering, Department of Civil Engineering and Surveying, South Africa Josiah Adeyemo --- University of Washington, United States of AmericaThe accurate prediction of suspended sediment flowing into reservoirs is very important during their design and operation stage. It is also of great significance in environmental engineering, hydroelectric equipment longevity, river aesthetics, pollution and channel navigability. Hence the development of... -
Morpho-agronomical characterisation of local and international sweetpotato germplasm from the South African collection
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Sonia IM Naidoo --- , South Africa Sunette M Laurie --- , South Africa Hussein Shimelis --- , South Africa Mark D Laing --- , South AfricaConsiderable genetic diversity is present amongst the sweet potato (Ipomoea batatas (L.) Lam.) accessions that can be selected for breeding. The Agricultural Research Council of South Africa maintains 360 sweetpotato accessions that were bred locally, and introductions from various regions... -
Application of metaheuristic algorithms in DC-optimal power flow
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Oluwafemi Ajayi --- , South Africa Nnamdi Nwulu --- , South Africa Uyikumhe Damisa --- , South AfricaThis paper presents the application of two metaheuristic algorithms (Exchange Market Algorithm and Ant Lion Optimizer) in solving the DC optimal power flow problem. The objective of this study is to minimize fuel costs associated with electricity generation. Advanced Interactive... -
Cross-shelf movement of Chrysaora fulgida (Scyphozoa; Discomedusae) off Namibia inferred from stable isotopes (δ15N and δ13C)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: H Skrypzeck --- , South Africa CD van der Lingen --- , South Africa MJ Gibbons --- , South AfricaLarge and small specimens of two species of metagenic Scyphozoa (true jellyfishes) can be found in nearshore waters off central Namibia throughout the year. Whereas populations of Chrysaora africana are largely restricted to inshore waters, C. fulgida occurs across the... -
Genetic diversity of the Ankober Serin (Crithagra ankoberensis) at Simien Mountains National Park and Guassa Community Conservation Area, Ethiopia
Item type: Journal Article • Journal: African Zoology • Authors: Abebayehu Dessalegn --- , Ethiopia Mundanthra Balakrishnan --- , Ethiopia Till Töpfer --- , Germany Lars Podsiadlowski --- , Germany Tilaye Wube --- , EthiopiaThe genetic diversity of the Ethiopian endemic Ankober Serin Crithagra ankoberensis was studied in two populations at Simien Mountains National Park and Guassa Community Conservation Area using five microsatellite markers. Blood samples were taken from 16 and 14 birds, respectively... -
Agricultural supply response for sunflower in South Africa (1947–2016): The partial Nerlovian framework approach
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Kenneth Nhundu --- , South Africa Colleta Gandidzanwa --- , South Africa Petronella Chaminuka --- , South Africa Manana Mamabolo --- , South Africa Sandile Mahlangu --- , South Africa Moraka N. Makhura --- , South AfricaThe study estimates sunflower supply response in South Africa using time series data from 1947 to 2016, modelled through the Nerlovian Partial Adjustment approach. Short- and long-run price elasticities of 0.238 and 0.313 respectively, suggest that farmers do not easily... -
Disaggregation and assessment of estuarine pressures at the country-level to better inform management and resource protection – the South African experience
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: L van Niekerk --- , South Africa S Taljaard --- , South Africa SJ Lamberth --- , South Africa JB Adams --- , South Africa SP Weerts --- , South Africa CF MacKay --- , South AfricaGlobally, the ability of estuaries to sustain functionality and productivity is deteriorating rapidly under ever-increasing anthropogenic pressures. We present a systematic approach to identify, characterise and rank global pressures affecting estuaries. Six main pressure categories are reviewed: freshwater flow modification;... -
Drivers of periphyton biomass in south-western Cape rivers, South Africa, and the implications for management
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: JL Ewart-Smith --- , South AfricaIn open-canopied temperate rivers, periphyton plays a pivotal role by converting dissolved nutrients into food for biota. International research suggests that periphyton is particularly responsive to flow and nutrient alterations and therefore ideally suited to aiding the prediction and monitoring... -
Flow alterations and nutrient loading reduce primary producer variability in a temporarily closed microtidal estuary in KwaZulu-Natal, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Monique Nunes --- , South Africa Daniel A Lemley --- , South Africa Janine B Adams --- , South AfricaPrimary producer responses to cumulative regulating factors were investigated in a temporarily closed microtidal estuary. We hypothesised that the phytoplankton chlorophyll-a concentration (Chl a) and invasive alien aquatic plant (IAAP) abundance would be highest during the low-flow season and that... -
An assessment of water and sediment quality of aquatic ecosystems within South Africa’s largest floodplain
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D van Rooyen --- , South Africa R Gerber --- , South Africa NJ Smit --- , South Africa V Wepener --- , South AfricaNdumo Game Reserve (NGR), a Ramsar site, situated in South Africa’s largest floodplain (Phongolo River floodplain) in northern KwaZulu-Natal, with important aquatic ecosystems: the Usuthu and Phongolo rivers and their associated floodplain lakes. While the Phongolo River is regulated, the... -
Zooplankton distribution and community structure as a function of environmental variables in the Niger River and its tributaries in Niger
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: H Souley Adamou --- Université de Toulouse, France B Alhou --- Université Abdou Moumouni de Niamey, Niger M Tackx --- Université de Toulouse, France F Azémar --- Université de Toulouse, FranceThe Niger River and its main tributaries (Sirba, Tapoa and Mékrou) in Niger were sampled during high and low water flow with the objectives of (1) comparing the taxonomic structure, diversity and abundance of the zooplankton community (rotifers, copepods, crustaceans)... -
A note on reducing resistance in snarks
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Imran Allie --- University of Cape Town,In this paper, we define new parameters which measure the edge uncolourability of cubic graphs. These parameters count the minimum number of vertex reductions required to render a 3-edge-colourable graph, given a cubic graph G. Two of these parameters we... -
Understanding the effects of climate change on Southern Ocean ecosystems
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CD McQuaid --- Rhodes University, South AfricaUnderstanding the future of Southern Ocean ecosystems requires approaches at micro to macro scales. The Southern Ocean has experienced both top-down and bottom-up perturbations driven by man. The removal of whales and finfish was a top-down disruption, removing enormous levels... -
Gradient estimates of a nonlinear Lichnerowicz equation under the Finsler-geometric flow
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Shahroud Azami --- Imam Khomeini International University, IranLet (Mn , F(t), m), t ∈ [0, T], be a compact Finsler manifold with F(t) evolving by the Finsler-geometric flow , where g(t) is the symmetric metric tensor associated with F, and h(t) is a symmetric (0, 2)-tensor. In... -
Water quality monitoring and measuring physicochemical parameters using wireless sensor networks
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: N Satyanarayana Murthy --- , India SF Ahamed --- , IndiaIn a world grappling with the dire consequences of poor sanitation and inadequate water conditions, there is an urgent need for a comprehensive solution. The staggering statistics of over 400 million affected cases and 15–25 million lives lost worldwide underscore... -
E-government’s role in enhancing foreign direct investment to sub-Saharan African countries: An application of system GMM
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Getahun Tolossa Adugna --- School of Economics, College of Business and Economics, University of Gondar, Ethiopia Wondemhunegn Ezezew Melesse --- School of Economics, College of Business and Economics, University of Gondar, Ethiopia Yinges Alemu Muche --- School of Economics, College of Business and Economics, University of Gondar, EthiopiaIn recent years, the provision of government services through electronic platforms has significantly increased due to the rapid development of digital technologies. The significant shift in digital governance is expected to have an effect on key macroeconomic variables through its... -
The cumulative prospect theory and fund flows in emerging markets
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Amit Pandey --- Indian Institute of Technology Roorkee, India Anil Kumar Sharma --- Indian Institute of Technology Roorkee, IndiaThis study is the first to examine the efficacy of the Cumulative Prospect Theory value of the past return (CPTV) to explain fund flow in emerging markets funds by considering the impact of fund managers’ characteristics and behavioural biases on... -
Well-posedness result for the flow of Maxwell viscoelastic fluid of White-Metzner type
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Djohra Dekhil --- University of Science and Technology Houari Boumdiene USTHB, Algeria Toufik Laadj --- University of Science and Technology Houari Boumdiene USTHB, Algeria Khaled M’hamed-messaoud --- University of Science and Technology Houari Boumdiene USTHB, AlgeriaIn this paper, we investigate the flow characteristics of an unsteady quasistatic Maxwell viscoelastic fluid of White-Metzner type within a three-dimensional bounded domain. Our objective is to establish the well-posedness of the resulting partial differential equations initial boundary value problem,... -
How and when does employees’ learning goal orientation contribute to taking charge behaviour? The roles of empowering leadership and work-related flow
Item type: Journal Article • Journal: Journal of Psychology in Africa • Authors: Lingnan Kong --- North China Electric Power University, China He Ding --- North China Electric Power University, China Sha Liu --- North China Electric Power University, China Shunkun Yu --- North China Electric Power University, China Chengju Qin --- North China Electric Power University, ChinaWe explored the mediating role of work-related flow and the moderating role of empowering leadership in the relationship between employees’ learning goal orientation and taking charge behaviour. Chinese employees (n = 313; female =57.51%; mean age =32.26 years, SD =... -
Flows with constant slope on the Klein bottle
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Luís Barreira --- Universidade de Lisboa, Portugal Jaume Llibre --- Universitat Autònoma de Barcelona, Spain Claudia Valls --- Instituto Superior Técnico, Universidade de Lisboa, PortugalWe consider smooth flows with constant slope on the 2-dimensional (flat) torus and on the (flat) Klein bottle. It is well known that for a flow with constant slope on the torus either all orbits are periodic or all orbits... -
Techno-economic and environmental assessment of battery integrated wind farm siting across offshore Nigeria
Item type: Journal Article • Journal: African Journal of Science, Technology, Innovation and Development • Authors: Gbubemi Kevin Akporhonor --- Energy and Environment Cranfield University, United KingdomThis study investigates the economic, technical, and environmental impacts of integrating a battery energy storage system (BESS) with an offshore wind farm near Koko Sea Port, Nigeria. As renewable energy curtailment increases and Nigeria’s energy demand grows, energy storage systems... -
Influence of the Benguela Upwelling System on the genetic connectivity of blacktail seabream Diplodus capensis across southern Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: WF Olivier --- Genetics and Microbiology, University of Pretoria, South Africa WM Potts --- Rhodes University, South Africa A-R Childs --- Rhodes University, South Africa C Santos --- Agostinho Neto University, Angola PW Shaw --- Aberystwyth University, R Henriques --- Genetics and Microbiology, University of Pretoria, South AfricaOceanographic features such as upwelling cells and currents contribute to shaping the evolutionary history of marine fishes, including species that may be important socio-economic resources. However, the impacts of these barriers are often cryptic and may change, particularly in a... -
Nehari manifold approach for a singular multi-phase variable exponent problem
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Mustafa Avci --- Athabasca University, CanadaThis paper is concerned with a singular multi-phase problem with variable singularities. The main tool used is the Nehari manifold approach. Existence of at least two positive solutions with positive-negative energy levels are obtained. For the illustration of the main... -
Comparative benchmarking of fertiliser uses for oilseed crop production in South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: HT Ottermann --- , South Africa SJ Haarhoff --- Stellenbosch University, South Africa KJ Truter --- , South Africa F Meyer --- , South Africa D van der Westhuizen --- , South Africa PA Swanepoel --- Stellenbosch University, South AfricaThis study comparatively benchmarks fertiliser use over two periods (2013–2015; 2021–2023) in South Africa's oilseed crop production [soybean (Glycine max), canola (Brassica napus) and sunflower (Helianthus annuus)] against global trends, with a focus on major oilseed exporters. It explores fertiliser... -
Delta-shocks and vacuums as flux-approximation limit of solutions to the Aw-Rascle model with time-dependent source
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Mengqi Cui --- Department of Mathematics, Yunnan Normal University, P.R. China Shuai Fan --- Department of Mathematics, Yunnan Normal University, P.R. China Yu Zhang --- Department of Mathematics, Yunnan Normal University, P.R. ChinaThe flux-approximation limit of solutions to the Aw-Rascle (AR) traffic flow model with time-dependent source is considered. First, the Riemann problem containing flux perturbation and generalized Chaplygin gas (GCG) pressure is solved. Then, it is proved that, as the flux...