Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635136
W. Wenzel, J. Berg, M. Bloem
Combining ability of R-lines with respect to malt quality and stem borer resistance was evaluated in two trials. Crosses between three R-lines and eight R-lines were made for malt quality and three R-lines and seven R-lines for stem borer resistance evaluation. The R-line RTx432 showed superior combining ability for both characteristics, indicating its potential value to the local sorghum industry.
{"title":"The combining ability of RTx432 for Sorghum malt quality and stem borer resistance","authors":"W. Wenzel, J. Berg, M. Bloem","doi":"10.1080/02571862.1998.10635136","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635136","url":null,"abstract":"Combining ability of R-lines with respect to malt quality and stem borer resistance was evaluated in two trials. Crosses between three R-lines and eight R-lines were made for malt quality and three R-lines and seven R-lines for stem borer resistance evaluation. The R-line RTx432 showed superior combining ability for both characteristics, indicating its potential value to the local sorghum industry.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"11 1","pages":"162-163"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75659758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635125
M. Fey, H. A. Dodds
The potentially acidifying impact of air pollution coupled with agriculture and forestry has stimulated interest in the spatial assessment of soil quality deterioration in the highveld and eastern escarpment region of South Africa. Current information on soils is available as 1:250 000-scale land type maps depicting areas of relatively uniform soil pattern for which there is a quantitative inventory of soil series distribution. The objective of this study was to convert this information into a regional map showing the sensitivity of soils to acidification. Topsoils from 143 modal profiles, representing 57 soil series of the binomial classification system, were analysed for acid neutralizing capacity (ANC) using a simple method of pH measurement in acetate buffer solution. The relationship between ANC and relevant textural and chemical properties was then employed to classify, directly or by pedogenic inference, all the 504 series in the binomial system into 4 sensitivity categories. Arclnfo geographic inf...
{"title":"Classifying the sensitivity of soils of the South African highveld to acidification","authors":"M. Fey, H. A. Dodds","doi":"10.1080/02571862.1998.10635125","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635125","url":null,"abstract":"The potentially acidifying impact of air pollution coupled with agriculture and forestry has stimulated interest in the spatial assessment of soil quality deterioration in the highveld and eastern escarpment region of South Africa. Current information on soils is available as 1:250 000-scale land type maps depicting areas of relatively uniform soil pattern for which there is a quantitative inventory of soil series distribution. The objective of this study was to convert this information into a regional map showing the sensitivity of soils to acidification. Topsoils from 143 modal profiles, representing 57 soil series of the binomial classification system, were analysed for acid neutralizing capacity (ANC) using a simple method of pH measurement in acetate buffer solution. The relationship between ANC and relevant textural and chemical properties was then employed to classify, directly or by pedogenic inference, all the 504 series in the binomial system into 4 sensitivity categories. Arclnfo geographic inf...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"49 1","pages":"99-103"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83650563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635126
M. Bosman, G. A. Agenbag
A number of staining procedures were evaluated after sodium dodecyl sulphate (SDS) Polyacrylamide gel (PAGE) electrophoretic runs of different wheat cultivars of the Western Cape. The staining method developed by Neuhoff, Arold, Taube and Ehrhardt, (1988) intensified a specific high molecular weight (HMW)-Glu-1 band in comparison with the other HMW-Glu-1 bands of a cultivar. This HMW-Glu-1 band is a genetic marker for good breadbaking quality. The protein content of this band, which showed a variation in its mobility and with a mass between 113.5 kDa and 103.5 kDa, was calculated by using laser densitometric scannings. This protein content can be expressed as a percentage of the total protein content of the SDS-soluble wheat protein of the specific cultivar and can be used to classify cultivars in different groups which correspond to their bread baking quality. This is, therefore, a fast, reliable and easy way to determine or predict breadbaking quality.
{"title":"A staining method to intensify a specific high molecular weight glutenin band and the calculation of the relative protein content of the band with laser densitometer scans","authors":"M. Bosman, G. A. Agenbag","doi":"10.1080/02571862.1998.10635126","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635126","url":null,"abstract":"A number of staining procedures were evaluated after sodium dodecyl sulphate (SDS) Polyacrylamide gel (PAGE) electrophoretic runs of different wheat cultivars of the Western Cape. The staining method developed by Neuhoff, Arold, Taube and Ehrhardt, (1988) intensified a specific high molecular weight (HMW)-Glu-1 band in comparison with the other HMW-Glu-1 bands of a cultivar. This HMW-Glu-1 band is a genetic marker for good breadbaking quality. The protein content of this band, which showed a variation in its mobility and with a mass between 113.5 kDa and 103.5 kDa, was calculated by using laser densitometric scannings. This protein content can be expressed as a percentage of the total protein content of the SDS-soluble wheat protein of the specific cultivar and can be used to classify cultivars in different groups which correspond to their bread baking quality. This is, therefore, a fast, reliable and easy way to determine or predict breadbaking quality.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"36 1","pages":"104-108"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81026809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635119
G. F. Marais, W. Wessels, M. Horn, F. Toit
A stem rust resistance gene, originally derived from Triticum tauschii accession RL5289 and present in the germplasm line 87M66-2-1, is here designated Sr45. Sr45 was found to be closely linked to Sr33 (9 ± 1.9 map units) and the centromere (21 ± 3.4 map units) on chromosome arm 1DS. Sr45 is believed to be the same gene as SrX. The Russian wheat aphid resistance gene, Dn5, was loosely linked (32 ± 5 map units) to Ep-D1b, which occurs on a translocation derived from T. ventricosum, and to the cn?D1 locus (37 ± 6.3 map units) on chromosome arm 7DL. Dn5 derives from T. aestivum accession Pl294994 which was found to express two novel Ep-1 alleles (proposed designations Ep-A1d and Ep-D1e). A gene (here designated Dn7) for Russian wheat aphid resistance that was derived from the rye accession, Turkey 77', mapped 14.5 ± 3.9 map units from Lr26 on the 1BL.1RS translocation.
{"title":"Association of a stem rust resistance gene (Sr45) and two Russian wheat aphid resistance genes (Dn5 and Dn7) with mapped structural loci in common wheat","authors":"G. F. Marais, W. Wessels, M. Horn, F. Toit","doi":"10.1080/02571862.1998.10635119","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635119","url":null,"abstract":"A stem rust resistance gene, originally derived from Triticum tauschii accession RL5289 and present in the germplasm line 87M66-2-1, is here designated Sr45. Sr45 was found to be closely linked to Sr33 (9 ± 1.9 map units) and the centromere (21 ± 3.4 map units) on chromosome arm 1DS. Sr45 is believed to be the same gene as SrX. The Russian wheat aphid resistance gene, Dn5, was loosely linked (32 ± 5 map units) to Ep-D1b, which occurs on a translocation derived from T. ventricosum, and to the cn?D1 locus (37 ± 6.3 map units) on chromosome arm 7DL. Dn5 derives from T. aestivum accession Pl294994 which was found to express two novel Ep-1 alleles (proposed designations Ep-A1d and Ep-D1e). A gene (here designated Dn7) for Russian wheat aphid resistance that was derived from the rye accession, Turkey 77', mapped 14.5 ± 3.9 map units from Lr26 on the 1BL.1RS translocation.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"20 1","pages":"67-71"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82317000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635129
J. Strauss, G. A. Agenbag
The aim of this study was to compare the withholding of water and the use of polyethylene glycol (PEG) as methods of inducing water stress in spring wheat cultivars (Triticum aestivum L.) grown in the Western Cape. Water stress was induced in two cultivars that had previously shown differences in drought tolerance. Proline accumulation in plants and the reduction of 2,3,5-triphenyltetrazoliumchloride (TTC) were used as indicators of water stress in the test plants. Proline accumulation proved to be a more sensitive indicator of water stress compared to TTC, showing significant increases with both the withholding of water and PEG as methods to induce water stress. Although both methods of stress induction proved to be effective, the withholding of water may be more appropriate due to the possibility of root injuries with PEG. Good control of climatic conditions and measurements of plant water potential will, however, be essential if the withholding of water is used to induce stress.
{"title":"A comparison of two methods of inducing water stress in wheat (Triticum aestivum L.)","authors":"J. Strauss, G. A. Agenbag","doi":"10.1080/02571862.1998.10635129","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635129","url":null,"abstract":"The aim of this study was to compare the withholding of water and the use of polyethylene glycol (PEG) as methods of inducing water stress in spring wheat cultivars (Triticum aestivum L.) grown in the Western Cape. Water stress was induced in two cultivars that had previously shown differences in drought tolerance. Proline accumulation in plants and the reduction of 2,3,5-triphenyltetrazoliumchloride (TTC) were used as indicators of water stress in the test plants. Proline accumulation proved to be a more sensitive indicator of water stress compared to TTC, showing significant increases with both the withholding of water and PEG as methods to induce water stress. Although both methods of stress induction proved to be effective, the withholding of water may be more appropriate due to the possibility of root injuries with PEG. Good control of climatic conditions and measurements of plant water potential will, however, be essential if the withholding of water is used to induce stress.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"48 1","pages":"121-122"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77894854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635128
E. Smit
Maize root rot is common in South Africa and various factors may influence disease severity. Phoma spp., Trichoderma spp., Fusarium spp., Macrophomina phaseolina (Tassi) Goid. and Exserohilum pedicellatum (Henry) Leonard and Suggs are the primary fungi isolated from infected roots. Since soil micro flora are affected by prevailing soil conditions, tillage practices may affect the incidence of soilborne fungi. Field trials, to determine the effect of tillage practices on disease severity, were carried out at Bloekomspruit and Mmabatho during the 1992/93, 1993/94 and 1994/95 seasons. Tillage practices applied were no-till, rip, mouldboard, disc and chisel plough treatments. Fungi were isolated from discoloured and apparently clean root tissue, quantified and identified. Significant interactions between isolation frequencies, effect of seasons and tillage practices were recorded for Fusarium equiseti (Corda) Sacc., Fusarium moniliforme Sheldon, Exserohilum pedicellatum and Phoma spp. at Bloekomspruit and Mac...
{"title":"Complex of root infecting fungi isolated from maize grown under various tillage practices","authors":"E. Smit","doi":"10.1080/02571862.1998.10635128","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635128","url":null,"abstract":"Maize root rot is common in South Africa and various factors may influence disease severity. Phoma spp., Trichoderma spp., Fusarium spp., Macrophomina phaseolina (Tassi) Goid. and Exserohilum pedicellatum (Henry) Leonard and Suggs are the primary fungi isolated from infected roots. Since soil micro flora are affected by prevailing soil conditions, tillage practices may affect the incidence of soilborne fungi. Field trials, to determine the effect of tillage practices on disease severity, were carried out at Bloekomspruit and Mmabatho during the 1992/93, 1993/94 and 1994/95 seasons. Tillage practices applied were no-till, rip, mouldboard, disc and chisel plough treatments. Fungi were isolated from discoloured and apparently clean root tissue, quantified and identified. Significant interactions between isolation frequencies, effect of seasons and tillage practices were recorded for Fusarium equiseti (Corda) Sacc., Fusarium moniliforme Sheldon, Exserohilum pedicellatum and Phoma spp. at Bloekomspruit and Mac...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"127 1","pages":"116-120"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77892809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/02571862.1998.10635113
R. Bennet
The mechanistic basis of Al rhizotoxicity was investigated through a time-based analysis of the growth reactions seen in hydroponically-grown roots of wheat isolines (IS and IT) differing in Al tolerance, when exposed to 75 μM Al (pH 4.1) for times ranging between 2 minutes and 48 h. Notwithstanding genotypic differences in the timing and the magnitude of the reactions, it was clear that the root growth adjustments made in response to Al involved three phases, 1) the primary response (IS and IT ≤ 60 min) which produced a net increase in root extension growth, 2) an intermediate period of growth inhibition (IS, 6 h; IT, 24 h.) and 3) recovery (IT 48 h) which included growth stimulation. Close relationships also emerged between the time-dependent, Al-induced increases and decreases in root extension growth and the volume (length) of the root cap and the length of root epidermal cells which suggested that cap volume and root epidermal cell extensibility may also be components of the Al response network. Thes...
{"title":"The aluminium response network in wheat (Triticum aestivum L.): I. The root growth reactions","authors":"R. Bennet","doi":"10.1080/02571862.1998.10635113","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635113","url":null,"abstract":"The mechanistic basis of Al rhizotoxicity was investigated through a time-based analysis of the growth reactions seen in hydroponically-grown roots of wheat isolines (IS and IT) differing in Al tolerance, when exposed to 75 μM Al (pH 4.1) for times ranging between 2 minutes and 48 h. Notwithstanding genotypic differences in the timing and the magnitude of the reactions, it was clear that the root growth adjustments made in response to Al involved three phases, 1) the primary response (IS and IT ≤ 60 min) which produced a net increase in root extension growth, 2) an intermediate period of growth inhibition (IS, 6 h; IT, 24 h.) and 3) recovery (IT 48 h) which included growth stimulation. Close relationships also emerged between the time-dependent, Al-induced increases and decreases in root extension growth and the volume (length) of the root cap and the length of root epidermal cells which suggested that cap volume and root epidermal cell extensibility may also be components of the Al response network. Thes...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"22 1","pages":"38-45"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89550307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1080/02571862.1997.10635103
J. Ward, D. Nowell, M. Laing, M. Whitwell
Grey leaf spot (Cercospora zeae-maydis Tehon and E.Y. Daniels) has seriously decreased the yields of maize in KwaZulu-Natal, South Africa, and has been identified in neighbouring provinces and countries. Since no commercially grown hybrids have been identified to be resistant to the disease, a study was initiated to assess the susceptibility of hybrids to the pathogen. The objective of the study was to identify high-yielding hybrids that were least susceptible to grey leaf spot, and to identify hybrids best suited to stubble and conventionally ploughed tillage systems. Linear regression of relative yield against relative disease severity identified high-yielding maize hybrids, including PAN 6480, that were least susceptible, SNK 2888, was tolerant, whilst PAN 6528 was most susceptible to disease. The susceptibility of hybrids to grey leaf spot was affected similarly by stubble and conventional tillage practices over the seasons of the study. In the 1993/94 season with adequate rainfall and favourable for ...
{"title":"Susceptibility of maize hybrids to grey leaf spot under two tillage systems in South Africa","authors":"J. Ward, D. Nowell, M. Laing, M. Whitwell","doi":"10.1080/02571862.1997.10635103","DOIUrl":"https://doi.org/10.1080/02571862.1997.10635103","url":null,"abstract":"Grey leaf spot (Cercospora zeae-maydis Tehon and E.Y. Daniels) has seriously decreased the yields of maize in KwaZulu-Natal, South Africa, and has been identified in neighbouring provinces and countries. Since no commercially grown hybrids have been identified to be resistant to the disease, a study was initiated to assess the susceptibility of hybrids to the pathogen. The objective of the study was to identify high-yielding hybrids that were least susceptible to grey leaf spot, and to identify hybrids best suited to stubble and conventionally ploughed tillage systems. Linear regression of relative yield against relative disease severity identified high-yielding maize hybrids, including PAN 6480, that were least susceptible, SNK 2888, was tolerant, whilst PAN 6528 was most susceptible to disease. The susceptibility of hybrids to grey leaf spot was affected similarly by stubble and conventional tillage practices over the seasons of the study. In the 1993/94 season with adequate rainfall and favourable for ...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"36 1","pages":"169-176"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85637908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1080/02571862.1997.10635104
A. D. Toit, J. Booysen, J. J. Human
A 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.
{"title":"Use of linear regression and correlation matrix in the evaluation of CERES3 (Maize)","authors":"A. D. Toit, J. Booysen, J. J. Human","doi":"10.1080/02571862.1997.10635104","DOIUrl":"https://doi.org/10.1080/02571862.1997.10635104","url":null,"abstract":"A 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.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"8 350 1","pages":"177-182"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88042620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-01DOI: 10.1080/02571862.1997.10635100
C. V. van Huyssteen, F. Ellis, J. Lambrechts
Existing 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 a relatively good indicator (r = 0.77) of duration of free water. For this study the equation: Duration of free water = 2.35 x Huedry + 5.79 x Valuedry − 7.31 Chromadry – 27.89 can be used to predict duration of free water in diagnostic red apedal B, yellow-brown apedal B, yellow E and grey E horizons. It seems that the present colour definitions for diagnostic horizons in the South African soil classification system are sufficiently accurate to distinguish meaningfully between these horizons with respect to duration of free water.
现有的颜色指数进行了评估，以确定其与水饱和度持续时间的相关性，在格拉博地区，西开普。相关系数在0.31 ~ 0.63之间。更简单的颜色指数被开发出来。干土颜色是自由水分持续时间较好的指标(r = 0.77)。在本研究中，方程:游离水持续时间= 2.35 x Huedry + 5.79 x Valuedry−7.31 Chromadry - 27.89可用于预测诊断红色花瓣B、黄褐色花瓣B、黄色E和灰色E层的游离水持续时间。目前南非土壤分类系统中诊断层的颜色定义似乎足够准确，足以在自由水的持续时间方面对这些层进行有意义的区分。
{"title":"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","authors":"C. V. van Huyssteen, F. Ellis, J. Lambrechts","doi":"10.1080/02571862.1997.10635100","DOIUrl":"https://doi.org/10.1080/02571862.1997.10635100","url":null,"abstract":"Existing 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 a relatively good indicator (r = 0.77) of duration of free water. For this study the equation: Duration of free water = 2.35 x Huedry + 5.79 x Valuedry − 7.31 Chromadry – 27.89 can be used to predict duration of free water in diagnostic red apedal B, yellow-brown apedal B, yellow E and grey E horizons. It seems that the present colour definitions for diagnostic horizons in the South African soil classification system are sufficiently accurate to distinguish meaningfully between these horizons with respect to duration of free water.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"14 1","pages":"154-157"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88379623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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