| Using Ground Penetrating Radar to investigate spoil layers in rehabilitated minesoils | Paterson, D. G. | 1999 |
KeywordsGround penetrating radar, mine rehabilitation, soil mapping, spoil material AbstractOpencast coal mining on the Highveld of Mpumalanga involves the disturbance of highly productive soils, which must then be rehabilitated on top of the mined spoil. Various problems in this process may occur, however, which may lead to water-logging, compaction and/or decreased soil volume. Ground penetrating radar (GPR) is a useful technique in the characterisation of the rehabilitated soil and in determining the depth contours of the spoil layer. Studies with GPR were conducted at three rehabilitated opencast coal mines. In most cases GPR was able to clearly detect the top of the spoil layer and thus identify the variations in soil depth covering the spoil. Three-dimensional imaging can be achieved by means of a grid system, thereby identifying basins which could cause waterlogging. Advantages in the use of GPR include its capacity for obtaining continuous imagery and penetration to greater depths than is possible by soil augering. Time, manpower and financial savings can be achieved, increasing the potential to improve post-mining agricultural conditions. AuthorsPaterson, D. G. and Laker, M. C. Year Published1999 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1999.10634998 This article contributed by:
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| Using different sample holders in determining protein and moisture content in whole wheat flour by means of Fourier transform near infrared (FT-NIR) spectroscopy | van Zyl, L. | 2001 |
KeywordsFourier transform near infrared spectroscopy, moisture, protein, sample holder AbstractFourier transform near infrared (FT-NIR) spectroscopy was used to record the spectra of 92 whole wheat flour samples presented in three different sample holders. The conventional sample cup with a sapphire-glass base (provided with the spectrophotometer), borosilicate-glass vials and soda-glass vials were used. Calibrations were derived for protein and moisture content, respectively, of whole wheat flour by performing partial least square (PLS) regression on multiplicative scatter corrected (MSC) spectra and tested using independent validation procedures. Best results were obtained with the sample set analysed in the borosilicate-glass vials, although not significantly different (P > 0.05). The standard error of prediction (SEP), root mean standard error of prediction (RMSEP) and the correlation coefficient (r) were, respectively, 0.5%, 1.16% and 0.92 for the protein calibration model, and 0.15%, 0.38% and 0.94 for the moisture calibration model. The differences in spectral data due to the use of the different sample holders were investigated using correlation coefficients (r) and maximum distances (d). The significance of differences in prediction results was determined by performing an analysis of variance (ANOVA) on predicted protein and moisture values. Differences within each type of sample holder were also determined. All differences were found to be statistically insignificant (P > 0.05). The conventional sample cup can therefore be replaced by one of the more convenient vial types where each sample can be stored and presented to the spectrophotometer individually. Authorsvan Zyl, L., Manley, M. and Osborne, B. G. Year Published2001 PublicationSouth African Journal of Plant and Soil Locations- Napier, South Africa (-34.4767, 19.8903)
- Moorreesburg, Western Cape, South Africa (-33.15, 18.6667)
- Jonaskraal, South Africa (-34.3956, 19.9018)
- Dunhye Park (-34.2314, 19.4252)
- Heidelberg, South Africa (-34.0902, 20.9501)
- Boontjieskraal, South Africa (-34.2129, 19.3318)
- Riebeeck-Wes (-33.3521, 18.87)
- Welgevallen, Western Cape, South Africa (-33.9477, 18.8617)
DOI10.1080/02571862.2001.10634403 This article contributed by:
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| Using canonical variate analysis to group small white bean cultivars canned in tomato sauce according to their canning quality | van der Merwe, M. | 2007 |
KeywordsCanning quality, canonical variate analysis, choice grade, laboratory scale canning, small white bean cultivars AbstractA laboratory-scale canning and evaluation method was employed to evaluate the canning quality of small white beans over cultivars, localities and seasons. Four small white bean cultivars, representing 15 localities from the 2001/02 season and six cultivars representing 17 localities from the 2002/03 season (n = 162 samples) were evaluated by determining the hydration coefficient, percentage washed drained weight, visual appearance, splits, size, texture, clumping and colour after canning. The data were interpreted using canonical variate analysis (CVA). Standard grade quality cultivars, PAN 185 and OPS-KW1, were used as references for the standard grade group and Teebus as the reference for choice grade. According to the CVA results, Teebus RR1, PAN 120, PAN 121 and PAN 123 corresponded with the choice grade standard canning quality of Teebus. These laboratory canning and evaluation methods in conjunction with CVA allowed cultivars to be grouped according to canning grades. The discriminative equations for CV1 and CV2, derived from the CVA, might be employed as a model in order to group the canning quality of samples to indicate similarity to a reference. After further verification this model might allow samples not included in these trials, but grown under similar conditions, to be evaluated for canning quality similarity to the choice grade reference. Authorsvan der Merwe, M., Osthoff, G. and Pretorius, A. J. Year Published2007 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2007.10634787 This article contributed by:
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| User-friendly model for chemical equilibrium of CaSO4 solutions | Jovanovic, N. Z. | 2003 |
KeywordsChemical equilibrium, computer software, gypsum AbstractUser-friendly Windows software (ChemEq) was developed for calculation of solution chemical equilibrium and precipitation- dissolution of lime and gypsum. ChemEq calculates ionic concentrations and activities, pH, solid phase gypsum and lime, sodium adsorption ratio and electrical conductivity from initial concentrations of ions, gypsum and lime. The program is written in Delphi v. 5.0 and is available for use with Windows 98/ME/2000 and NT on an IBM-PC or compatible computer. The main applications are in the calculation of chemical equilibrium of CaSO4 solutions. AuthorsJovanovic, N. Z., Annandale, J. G. and Benadè, N. Year Published2003 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2003.10634916 This article contributed by:
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| Use of the SDSS test to predict the protein content and bread volume of wheat cultivars | de Villiers, O. T. | 1995 |
KeywordsBread volume, protein content, SDS sedimentation volume, wheat AbstractThe relationship between the sodium dodecyl sulphate sedimentation volume (SDSS test) and the protein content and bread volume of wheat cultivars was determined to ascertain whether the SDSS test could be used to predict these parameters of baking quality. This test proved to be a good indication of baking quality as the SDS sedimentation volumes were positively correlated with both protein content and bread volume of the cultivars. Nitrogen fertilization affected the SDS sedimentation volume as well as the protein content and bread volume, thereby affecting the relationship between these parameters. Higher correlation coefficients between the different parameters were found at higher nitrogen applications. Some of the correlation coefficients were affected by the locality where the wheat was grown. Authorsde Villiers, O. T. and Laubscher, E. W. Year Published1995 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1995.10634353 This article contributed by:
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| Use of the microwave oven for drying herbage samples in the field | Daines, T. | 1985 |
KeywordsDry matter, herbage, microwave oven drying, quality AbstractDrying of herbage samples in the field using a microwave oven powered by a portable generator has saved time and eliminated the transporting of samples to other stations for handling. Microwave drying is compared to drying in conventional forced-air ovens and the influence of microwaves on chemical analysis of plant material is discussed. AuthorsDaines, T. and Ingpen, R. A. Year Published1985 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1985.10634147 This article contributed by:
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| Use of solid waste bagasse from a paper mill as an organic amendment and its effect on some soil properties: a case study | Hughes, J. C. | 2001 |
Keywordspaper mill bagasse waste, soil chemical properties, soil temperature, sugar cane growth AbstractAt a paper mill in KwaZulu-Natal, South Africa bagasse waste was disposed of by burying it in a layer resulting in variable sugar cane growth. The waste was mostly organic fibres, had a high water holding capacity, and contained small amounts of Ca, K, P and N. The soils were sandy with low water holding capacities and organic matter contents. Soil temperatures up to 38°C were measured in treated soils, compared to about 22°C in untreated soils. Treated soils contained more total cations, and variations in the sodium adsorption ratio and electrical conductivity of soil saturation extracts were not great or consistent across sites, suggesting neither excessive soil salinity nor sodicity. Field observations showed that the best cane growth was on soils that had been treated with the waste. Poor growth was found, either on recently treated sites or, on untreated areas within a larger treated area owing to poor distribution of the waste. Changing the method of application to mix the waste into the soil would facilitate decomposition, and avoid the problems of high soil temperatures and the creation of anaerobic conditions which discouraged root growth. AuthorsHughes, J. C. and Girdlestone, S.
J.A. Year Published2001 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2001.10634416 This article contributed by:
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| Use of linear regression and correlation matrix in the evaluation of CERES3 (Maize) | du Toit, A. S. | 1997 |
KeywordsCERES-Maize, Linear regression, Correlation matrix. AbstractA historical data set (soil water content, growth, phenology and yield) consisting of six cultivars and three planting dates was used to evaluate the CERES3 crop growth model. Linear regression and correlation matrix were used to identify algorithms in the model in need of calibration. Results indicated that the model simulates yield and kernel number with low accuracy under local conditions. The number of ears per plant and water stress before and during silking were identified as factors that could explain the low accuracy. Authorsdu Toit, A. S., Booysen, J. and Human, J. J. Year Published1997 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1997.10635104 This article contributed by:
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| Use of ethephon and chlormequat chloride to manage plant height and lodging of irrigated barley (cv. Puma) when high rates of N-fertiliser are applied | Ramburan, S. | 2007 |
KeywordsChlormequat chloride, ethephon, grain yield, lodging, plant height AbstractThe objective of this study was to evaluate the effects of the plant growth regulators (PGR's) chlormequat, ethephon and their combination on plant height, lodging, grain yield and yield components of ‘Puma’ barley with differing amounts of N (120, 150 & 180 kg N ha−1). The PGR treatments and a water control were applied at three times of application (TOA): the beginning of stem elongation, at the flag leaf stage, or as a split (double) application at elongation and the flag leaf stage at two localities (Bethlehem and Vaalharts). Field trials were planted as 4 × 32 factorials in RCBD's with 4 replications in the 2004 and 2005 seasons. Plant height, lodging (at Vaalharts) and grain yield (at both sites) were significantly reduced with applications of ethephon and the PGR combination at the flag leaf stage and as a split application. Chlormequat application alone did not produce a response. Yield reductions with ethephon and the PGR combination were attributed to reductions in grains spike−1 and mass grain−1. Higher N levels increased lodging and simultaneously reduced grain yields, however, applications of ethephon significantly controlled lodging at higher N levels. Ethephon and the PGR combination, applied at the flag leaf stage, can be utilized as lodging controlling tools with ‘Puma’ in environments conducive to lodging. AuthorsRamburan, S. and Greenfield, P. L. Year Published2007 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.2007.10634806 This article contributed by:
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| Use of estimated leaf water potential for irrigation timing of wheat | Nel, A. A. | 1991 |
KeywordsWheat, irrigation scheduling, leaf water potential, yield, evapotranspiration AbstractA regression model with which the leaf water potential (LWP) of wheat can be estimated from soil water content and potential evapotranspiration was developed from data generated during 1986. This model was used during the 1988 wheat season to decide when to relieve crop water stress by irrigation. Seven values of LWP, viz. −1.2; −1.4; −1.6; −1.8; −2.0; −2.2 and −2.4 MPa were considered as possible threshold values for irrigation. The soil water content, determined twice weekly, was used to estimate actual evapotranspiration. Midday LWP was determined on selected cloudless days and found to be most suitable as an irrigation timing criterion for several reasons. Firstly, the ratio evapotranspiration/pan evaporation was at least as well related to LWP as to soil water status. Secondly, strong relationships between grain yield, seasonal evapotranspiration, peak evapotranspiration rate and threshold LWP exist, and finally, indications are that yields near the upper limit of the evapotranspiration-yield relationship are ensured. Leaf water potential for irrigation timing purposes could be satisfactorily estimated by the model if calibrated over a sufficiently large range of leaf water potentials. The threshold potential for maximum water use efficiency was −1.82 MPa and for maximum yield −1.44 MPa. AuthorsNel, A. A. and Dijkhuis, F. J. Year Published1991 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1991.10634586 This article contributed by:
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