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The base status criterion in South African soil classification
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: M.V. Fey --- Department of Agronomy, Republic of South Africa M.J. Donkin --- , Republic of South AfricaEvidence is considered which indicates that the sum of extractable bases and acidity, termed the effective cation exchange capacity (ECEC), is a more reliable criterion than the S-value (sum of exchangeable bases only) for differentiating soils in terms of the... -
Die invloed van grondsuurheid op koringkultivars (Triticum aestivum L.) met verskillende vlakke van aluminiumverdraagsaamheid in die Oos-Vrystaat. I. Opbrengs
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: O. J.H. Bosch --- , Republlekvan Suid-Afrika W.M. Otto --- , Republlekvan Suid-Afrika J.J. Human --- Departement Agronomie, Republiek van Suid-Afrika'n Veldproef is uitgevoer oor twee groeiseisoene (1993 en 1994) in die Oos-Vrystaat om te bepaal waiter opbrengsverskille daar bestaan tussen verskillende koringkultivars wat varieër in aluminium (Al) -verdraagsaamheid. Vier verskillende pH- en suurversadigingsvlakke is gebruikom nege koringkultivars se opbrengsverskille... -
The relationship between subsoil colour and degree of wetness in a suite of soils in the Grabouw district, Western Cape I. Characterization of colour-defined horizons
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.W. van Huyssteen --- , South Africa F. Ellis --- , South AfricaSoil colour is an easily identifiable property that is invariably used as a parameter in all soil classification systems including the system used in South Africa. To test the hypothesis that soil colour is a reflection of the soil water... -
The relationship between subsoil colour and degree of wetness in a suite of soils in the Grabouw district, Western Cape II. Predicting duration of water saturation and evaluation of colour definitions for colour-defined horizons
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.W. van Huyssteen --- , South Africa F. Ellis --- Faculty of Forestry, South Africa J. J.N. Lambrechts --- Faculty of Agricultural Sciences, South AfricaExisting colour indices were evaluated to determine their correlation with duration of water saturation, for a hydrosequence in the Grabouw district, Western Cape. Correlation coefficients ranged between 0.31 and 0.63. More simple colour indices were developed. Dry soil colour is... -
The relationship between soil morphology and soil water regime: preliminary results in the Weatherley catchment
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.W. van Huyssteen --- Department of Soil, Crop and Climate Sciences, Republic of South Africa P. A.L. le Roux --- Department of Soil, Crop and Climate Sciences, Republic of South Africa M. Hensley --- Department of Soil, Crop and Climate Sciences, Republic of South AfricaSoil water contents were measured for five years at Weatherley, an intensively instrumented catchment in the north eastern part of the Eastern Cape Province. Soil water contents are expressed in terms of average duration of saturation with water above 0.7... -
Duration of water saturation in selected soils of Weatherley, South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.W. van Huyssteen --- Department of Soil, South Africa P. A.L. le Roux --- Department of Soil, South Africa M. Hensley --- Department of Soil, South Africa T.B. Zere --- Department of Soil, South AfricaSoil water contents were measured weekly for six years (1997–2005) in the Weatherley catchment in the northern Eastern Cape Province of South Africa, and used to calculate average duration of water saturation above 70% of porosity (ADs>0.7). Data were used... -
Soil water variability in the Weatherley grassland catchment, South Africa: II. Soil water content
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: CW van Huyssteen --- Department of Soil, Crop and Climate Sciences, South Africa TB Zere --- Department of Soil, Crop and Climate Sciences, South Africa M Hensley --- Department of Soil, Crop and Climate Sciences, South AfricaSoil water content is a major factor that affects the hydrological response of a hillslope or catchment. It is therefore important to have reliable soil water content data to estimate catchment water yield. Daily soil water content (θ) data was... -
The effect of degree and duration of water saturation on selected redox indicators: pe, Fe2+ and Mn2+
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: K. Smith --- Department of Soil, Crop and Climate Sciences, South Africa C.W. van Huyssteen --- Department of Soil, Crop and Climate Sciences, South AfricaIt was previously hypothesised that reduction in the soil will set in at 70% water saturation (S0.7). This study aimed to determine the effect of different degrees and durations of water saturation on reduction in soil. Reduction was measured as... -
Relating the onset of reduction to degree of soil water saturation
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Kimberly Smith --- Department of Soil, Crop and Climate Sciences, South Africa Cornelius W van Huyssteen --- Department of Soil, Crop and Climate Sciences, South AfricaLiterature does not indicate the degree of water saturation at which reduction is expected to occur. This study therefore aimed to determine the degree of water saturation (S) at which reduction is initiated. Soil cores were packed to a bulk... -
Rapid colonisation of artificial substrates by macroinvertebrates in a South African lentic environment
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: AJ Booth --- Department of Ichthyology and Fisheries Science, South Africa WT Kadye --- Department of Ichthyology and Fisheries Science, South Africa T Vu --- Department of Ichthyology and Fisheries Science, South Africa M Wright --- Department of Ichthyology and Fisheries Science, South AfricaMacroinvertebrate colonisation patterns on artificial substrates were investigated in a small reservoir in the Eastern Cape, South Africa. Semi-closed 1 000 cm3 polythene netting cages filled with either brick, gravel, shredded plastic, or equal proportions of these three materials, were... -
Refined estimates of South African pelagic fish biomass from hydro-acoustic surveys: quantifying the effects of target strength, signal attenuation and receiver saturation
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JC Coetzee D Merkle CL de Moor NM Twatwa M Barange DS ButterworthThe biomass of small pelagic fish species off the coast of South Africa has been monitored since 1984 using hydro-acoustic survey techniques. These time-series of spawner biomass and recruitment estimates form the basis for management of both the South African... -
Revised estimates of abundance of South African sardine and anchovy from acoustic surveys adjusting for echosounder saturation in earlier surveys and attenuation effects for sardine
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CL de Moor DS Butterworth JC CoetzeeHydro-acoustic surveys have been used to provide annual estimates of May recruitment and November spawner biomass of the South African sardine Sardinops sagax and anchovy Engraulis encrasicolus resources since 1984. These time-series of abundance estimates form the backbone of the... -
Design and calibration of an acoustic telemetry system subject to upwelling events
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Singh --- Department of Environmental Affairs, South Africa NJ Downey --- , South Africa MJ Roberts --- Department of Environmental Affairs, South Africa DM Webber --- , Canada MJ Smale --- , South Africa MA van den Berg --- Department of Environmental Affairs, South Africa RT Harding --- Department of Environmental Affairs, South Africa DC Engelbrecht --- , South Africa BM Blows --- , South AfricaThe experiments described were designed to calibrate a hexagonal array of VEMCO VR2 receivers and transmitters (model V9P-6L-S256) in isothermal and stratified water columns off the south coast of South Africa. The array, configured with 500 m between receivers, was... -
Acoustic niche partitioning in an anuran community inhabiting an Afromontane wetland (Butare, Rwanda)
Item type: Journal Article • Journal: African Zoology • Authors: Ulrich Sinsch --- Institute of Integrated Sciences, Department of Biology, Germany Katrin Lümkemann --- Institute of Integrated Sciences, Department of Biology, Germany Katharina Rosar --- Institute of Integrated Sciences, Department of Biology, Germany Christiane Schwarz --- Institute of Integrated Sciences, Department of Biology, Germany Maximilian Dehling --- Institute of Integrated Sciences, Department of Biology, GermanyThe species richness and calling activity of an anuran community inhabiting an agricultural wetland area at 1645 m a.s.l. near Butare, Rwanda, was assessed using visual and acoustic transects. The community included 15 species which were readily distinguishable using morphological,... -
Assessing the utility of ALOS PALSAR and SPOT 4 to predict timber volumes in even-aged Eucalyptus plantations located in Zululand, South Africa
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Riyad Ismail --- Sappi Forests, South Africa Horst Kassier --- Sappi Forests, South Africa Morries Chauke --- Sappi Forests, South Africa Francesco Holecz --- Sarmap SA, Switzerland Nico Hattingh --- Sappi Forests, South AfricaIn commercial forestry, regular terrestrial enumerations of the growing stock are required for the valuation, sustain-able management and planning of current and future timber supplies. In this study we examined whether the combination of synthetic aperture radar (ALOS PALSAR) and... -
Wetland hydrology indicators of Maluti Mountains wetlands in Lesotho
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Botle E Mapeshoane --- Department of Soil, Crop and Climate Sciences, South Africa Cornelius W van Huyssteen --- Department of Soil, Crop and Climate Sciences, South AfricaHydric soil morphological features are generally accepted to be reliable indicators of wetland hydrology. The relationship between soil water saturation and soil morphological indices is evaluated in this study from bi-weekly water level data taken over a period of two... -
Liming guidelines for soils under wheat cropping in the eastern Free State, South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: HJJ van Zyl --- University of the Free State, South Africa CC du Preez --- University of the Free State, South AfricaSoil acidity hampers the sustainability of wheat production in the eastern Free State, South Africa. Specific guidelines for liming are needed by farmers and advisors to ameliorate this condition. In this study, soils from four representative wheat producing farms were...