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Articles published from 1984-2014.

Description

Publishes original articles and commentaries on research in the fields of fundamental and applied soil and plant science. Original research papers, short communications including germplasm registrations, relevant book reviews, commentaries on papers recently published and, exceptionally, review articles will be considered for publication in the Journal. Manuscripts considered will address aspects of: Agronomical and Horticultural research including breeding and genetics, cultivar evaluation, management, nutrition, physiology, production, and quality; Soil Science research including biology, chemistry, classification, fertility, mineralogy, pedology and hydropedology, physics, and soil and land evaluation of agricultural and urban ecosystems; Weed Science research including biological control agents, biology, ecology, genetics, herbicide resistance and herbicide-resistant crops, and physiology and molecular action of herbicides and plant growth regulators; Agro-climatology; Agro-ecology; Forage, Pasture and Turfgrass science including production and utilisation; Plant and Soil Systems Modelling; Plant–Microbe Interactions; Plant–Pest Interactions; and Plant–Soil Relationships.

latest article added on October 2013

ArticleFirst AuthorPublished
A review of research achievements on maize stem borer, Busseola fusca (Fuller) and Diplodia ear rot caused by Stenocarpella maydis (Berk. Sutton)Flett, B.C.2010

A review of research achievements on maize stem borer, Busseola fusca (Fuller) and Diplodia ear rot caused by Stenocarpella maydis (Berk. Sutton)

Keywords

Busseola fusca, Stenocarpella maydis, Zea mays

Abstract

Research that focused on maize production on the central Highveld of South Africa was traditionally, since the early twentieth century, dealt with by the Department of Agriculture at Potchefstroom. During the 1970s the Highveld Region at Potchefstroom assigned a group of researchers with an interest in maize to a unit termed the Summer Grain Centre that in 1992 became part of the Agricultural Research Council’s Grain Crops Institute. Members of this group in particular gave research attention to various aspects of crop protection in maize, including the soil insect complex, the maize stem borer complex, maize streak disease, the ear rot complex and various leaf diseases. This paper deals with research progress on the African stem borer, Busseola fusca, and ear rot caused by Stenocarpella maydis. The emphasis is on research with a practical application rather than that of an academic nature.

Authors

Flett, B.C. and Rensburg, J.B.J. van

Year Published

2010

Publication

South African Journal of Plant and Soil

Locations
    DOI

    10.1080/02571862.2010.10639972

    This article contributed by:

    Original

    An overview of the context and scope of wheat (Triticum aestivum) research in South Africa from 1983 to 2008Barnard, A.2010

    An overview of the context and scope of wheat (Triticum aestivum) research in South Africa from 1983 to 2008

    Keywords

    Agronomy, crop protection, cultivar adaptation, quality, wheat breeding

    Abstract

    The domestic requirement for wheat in South Africa is approximately 2.8 million tons and annually the shortfall on local production is imported to meet the demand. During the past 25 years two distinct wheat marketing mechanisms characterised the wheat industry, impacting significantly on both research and industry. In 1996 the single channel marketing system through the Wheat Board made way for a liberal marketing environment in which market forces of supply and demand determine price. This refocused most research activities on factors to lower input costs and risks, while increasing the profitability of wheat production. Significant challenges were experienced with much stricter milling and baking quality requirements impacting on not only the development of adapted wheat cultivars for South African conditions, but also on fertiliser and cultivar recommendations, as well as production practices. Minimum tillage, preharvest sprouting, as well as the threat of Russian wheat aphid and stripe rust were some of the pertinent challenges faced during this time. Significant scientific breakthroughs of international importance were made with regard to the physiological and biochemical nature of insect resistance and plant defence as well as the transfer of resistance genes from alien species. This review provides an overview of the most pertinent wheat research undertaken from 1983 to 2008.

    Authors

    Barnard, A., Pretorius, Z.A., Otto, W.M., Smit, H.A., Tolmay, V.L., Jordaan, J.P., Koekemoer, F.P., Purchase, J.L. and Tolmay, J.P.C.

    Year Published

    2010

    Publication

    South African Journal of Plant and Soil

    Locations
      DOI

      10.1080/02571862.2010.10639973

      This article contributed by:

      Original

      A review of the post harvest handling of fruits in South Africa over the past twenty five yearsDodd, M.2010

      A review of the post harvest handling of fruits in South Africa over the past twenty five years

      Keywords

      Cold chain, export, packaging, subtropical fruit, tropical fruit

      Abstract

      During the past 25 years there has been a tremendous amount of positive change in the post harvest handling of fruits in South Africa, primarily due to the adoption of many new technologies developed in response to changes in the industry. Important factors that impacted on the fruit industry during this time were a variable profitability due to large changes in the exchange rate of the Rand compared to other trading currencies and freeing up the market which has aided in the growth of the industry. This review provides an overview of the scientists and developments in the citrus, avocado, mango, litchi, pome fruit, table grape, stone fruit including plums, nectarine, peach and apricot industries. The fruit industry is vitally important to South Africa as a foreign currency earner and a large provider of stable employment.

      Authors

      Dodd, M., Cronje, P., Taylor, M., Huysamer, M., Kruger, F., Lotz, E. and Merwe, K. van der

      Year Published

      2010

      Publication

      South African Journal of Plant and Soil

      Locations
      DOI

      10.1080/02571862.2010.10639974

      This article contributed by:

      Original

      Soil compaction under sugar cane (Saccharum hybrid sp.) cropping and mechanization in MauritiusCheong, L.R. Ng2009

      Soil compaction under sugar cane (Saccharum hybrid sp.) cropping and mechanization in Mauritius

      Keywords

      Bulk density, controlled traffic, mechanized harvesting, water infiltration rate

      Abstract

      Abstract Farm machinery is increasingly used in sugar cane production in Mauritius and is expected to cause soil compaction. A study was undertaken to ascertain whether the five major cane-growing soil groups of Mauritius were being compacted as a result of sugar cane cropping and mechanized harvesting. Bulk density was measured in situ using the excavation method and stabilized infiltration rate was determined with the CSIRO disc per-meameter on pristine soils under native vegetation, manually harvested sugar cane soils and mechanically harvested sugar cane soils. Bulk density results were generally not significantly different between pristine soils and manually harvested soils or between manually harvested soils and mechanically harvested soils. The only exception was in the super-humid Latosolic Brown Forest soil, where bulk density was significantly higher in the manually harvested soil by up to 0.4 g cm- 3 compared to the pristine soil. The stabilized infiltration rate of the sub-humid Low Humic Latosol and Latosolic Reddish Prairie soils was significantly higher with manually harvested sugar cane under irrigated conditions compared to pristine conditions, increasing from about 100 mm h- 1 to more than 200 mm h- 1. The mechanically harvested soils had significantly lower stabilized infiltration rate than the manually harvested soils, a minimum value of 55 mm h- 1 being measured in the Humic Latosol. It appears that compaction is not serious enough to affect sugar cane yield, as the bulk density of the soils under sugar cane in Mauritius varies between 1.0 and 1.3 g cm- 3, still lower than the threshold values of 1.5 to 1.7 g cm- 3 that were determined for other countries. However, the threshold values applicable for Mauritius must be determined before any firm conclusion can be drawn. There is a greater risk of runoff and erosion under high intensity rainfall with mechanized harvesting, and management of sugar cane plantations should aim at reducing or alleviating topsoil compaction. It is therefore suggested that minimum tillage and controlled traffic are the two most appropriate strategies for reducing compaction in the sugar industry of Mauritius.

      Authors

      Cheong, L.R. Ng, Kee Kwong, K.F. Ng and Preez, C.c. Du

      Year Published

      2009

      Publication

      South African Journal of Plant and Soil

      Locations
      DOI

      10.1080/02571862.2009.10639955

      This article contributed by:

      Original

      Agricultural suitability of dune system and Limpopo Basin soils near Xai-Xai, MozambiqueSamimi, C2009

      Agricultural suitability of dune system and Limpopo Basin soils near Xai-Xai, Mozambique

      Keywords

      Arenosol, dune soils, Fluvisol, South-East Africa, tropical soils

      Abstract

      Abstract Quaternary dune systems, as well as the Limpopo Basin near the rural city of Xai-Xai in southern Mozambique were studied concerning their soil fertility and sustainability for crop cultivation. Due to population growth, most sites, which are not overbuilt, are used for crop production. The Arenosols and Regosols of the dune area have slope of 20° and sandy textures. A poor water-holding capacity and a low capability of bonding nutrients are the consequence. A lack of food prevents a disciplined crop rotation including longer fallow periods. Despite persistent cultivation for decades, the soils have a high base saturation, but already a slight decline in the base saturation has considerable effects on crop quality. Shifting cultivation along the coastal dunes leads to a massive clearing of woodlands which destabilises the sensitive dune systems and exposes them to erosion. The Fluvisols of the Limpopo River valley on the other hand cannot be used without restrictions either. High salt contents influence plant growth and the clayey soils constrain root penetration, water availability, drainage and cultivation. Nevertheless, the soils are rich in nutrients and organic matter, and there is no water stress, even during the dry season. The valley soils appear to be a reasonable platform for agriculture.

      Authors

      Samimi, C, Brandt, M. and Bäumler, R.

      Year Published

      2009

      Publication

      South African Journal of Plant and Soil

      Locations
      DOI

      10.1080/02571862.2009.10639956

      This article contributed by:

      Original

      Obtaining the parameters required to model labile phosphorus for South African soilsPreez, C.c. Du2009

      Obtaining the parameters required to model labile phosphorus for South African soils

      Keywords

      Modelling, phosphorus, soil parameters, SWB-Sci

      Abstract

      Abstract Modelling phosphorus (P) in the environment can increase our understanding of potential transfer pathways into receiving water bodies as well as the plant availability of this nutrient in soil. Many current models make use of algorithms originally developed for the EPIC model over two decades ago. These algorithms were developed primarily using continental USA soils. Obtaining the required input parameters can therefore be challenging when applying this approach to soils not classified according to the USA system, and for soils for which similar parameters are not available. In this paper, new equations for the estimation of labile P from Ambic P, Bray 2 P and the modified ISFEI method are proposed. Guidelines for the classification of South African soils as calcareous, slightly weathered and highly weathered are further suggested, and we propose that only topsoil properties be used for this purpose. Depending on the amount of soil information available, this classification can be achieved using the clay fraction SiO2:Al2O3 molecular ratio, the sum of exchangeable Ca, Mg, K and Na, or a newly proposed categorization system for South African soil forms. It is clear that the above approaches should be thoroughly tested and relevant local research carried out to improve our ability to model P in South African soils.

      Authors

      Preez, C.c. Du, Annandale, J.G., der Laan, M. Van and Lorentz, S.A.

      Year Published

      2009

      Publication

      South African Journal of Plant and Soil

      Locations
      DOI

      10.1080/02571862.2009.10639957

      This article contributed by:

      Original

      Attempts to obtain Huanglongbing resistant or tolerant sweet orange by embryo rescue from healthy chimeras of diseased citrus fruitVuuren, S.P. Van2009

      Attempts to obtain Huanglongbing resistant or tolerant sweet orange by embryo rescue from healthy chimeras of diseased citrus fruit

      Keywords

      Embryo rescue, greening, polymerase chain reaction, psylla

      Abstract

      Abstract Huanglongbing remains a threat in the cooler citrus production areas of South Africa despite restrictions on the movement of citrus material from infected areas, cultural control measures, planting of healthy certified trees and the eradication of infected material. The ultimate control strategy would be the use of resistant plant material. Attempts to obtain resistance with conventional breeding have been unsuccessful. A new approach is to utilize embryo rescue of seed from healthy chimera sections of diseased fruit. The embryos were obtained from wide, asymptomatic sections of symptomatic fruit and cultured on Murashige and Tucker medium. Once the embryos developed to approximately 1 cm, they were micro-grafted to virus-free rootstocks. After further development to 10 to 15 mature buds, they were multiplied on virus-free rootstocks by budding. Growing shoots were challenged with “Candidatus Liberibacter africanus” via the psylla insect vector, Trioza erytreae Del G. for seven days on a young shoot. Afterwards, the psylla were collected from the plants and tested by polymerase chain reaction (PCR) and dot blot hybridisation, using the primer pair A2/J5, or probes to the amplicon, to determine if the insects used were infectious. Three months after the Liberibacter challenge, the same primer pair was used to evaluate the plants by PCR for the presence of the bacterium. Two clones remained negative after challenge, but the ultimate evaluation will be in the field where they will be exposed to repeated natural infection by the insect vector.

      Authors

      Vuuren, S.P. Van and Manicom, B.Q.

      Year Published

      2009

      Publication

      South African Journal of Plant and Soil

      Locations
      DOI

      10.1080/02571862.2009.10639958

      This article contributed by:

      Original

      Development of Phakopsora pachyrhizi on soybean at controlled temperature, relative humidity and moisture periodsPretorius, Z.A.2009

      Development of Phakopsora pachyrhizi on soybean at controlled temperature, relative humidity and moisture periods

      Keywords

      Asian soybean rust (ASR), epidemiology, lesion size, number of pustules

      Abstract

      Abstract The influence of temperature, relative humidity (RH) and moisture period (MP) was studied in relation to infection of soybean plants (Glycine max (L.) Merr.) by Asian Soybean Rust (ASR) caused by Phakopsora pachyrhizi Syd. Disease development was investigated at 15, 19, 21, 24, 26, 28 and 30°C and 6, 9, 12, 14 and 16 h MP at 75–80%, 85–90% and 95–100% RH. Following treatments in an electronically controlled dew chamber, plants were placed in a growth chamber (21-22°C, 80% RH). Number of pustules per lesion (abaxial leaf surface) and lesion size (abaxial and adaxial leaf surfaces) were calculated at 21 days after inoculation. The expression of disease was greatly influenced by post-inoculation temperatures, RH and MP. The highest number of pustules per lesion occurred at 21–24°C at all RH and MP levels tested. However, the number of pustules per lesion was significantly higher at both 85–90% and 95–100% than at 75–80% RH. On the adaxial leaf surface, lesion size only increased significantly at 75–80% RH after a 16 h MP reaching a maximum length at 24°C. At 85–90% and 95-100% RH, lesion size increased significantly after a 14 h MP with the largest lesion size produced at 21°C and 24°C, respectively. On the abaxial leaf surface, lesion size increased significantly after a 16 h MP at 75–80%, whereas at 85-90% and 95–100% RH, an increase in lesion size was found after a 14 h MP and was largest at 21°C after a 16 h MP. Infection did not occur on plants incubated at 15°C and 30°C at 85–90% and 95–100% RH whereas at 75–80% infection did not occur on plants incubated at 15°C, 19°C and 30°C, regardless of MP. No infection occurred with a MP of 6 h at any temperature and RH level tested. The results suggest that ASR is unlikely to occur at high temperatures (>28°C) and short MP (<6 h). However, in soybean production areas of South Africa where moisture is provided by mist, light rain, irrigation or dew, with temperatures of 21–28°C and RH of 75–100%, infection can occur after a 6 h MP. Success of infection is enhanced if plants are exposed to these conditions for 16 h.

      Authors

      Pretorius, Z.A., Nunkumar, A. and Caldwell, P.M.

      Year Published

      2009

      Publication

      South African Journal of Plant and Soil

      Locations
        DOI

        10.1080/02571862.2009.10639959

        This article contributed by:

        Original

        Spatial variation of soil and plant properties and its effects on the statistical design of a field experimentVenter, A.2009

        Spatial variation of soil and plant properties and its effects on the statistical design of a field experiment

        Keywords

        Block design, covariate, geostatistics, randomization, spatial variability, yield

        Abstract

        Abstract The standard procedure in field experimentation is to use a randomized complete block (RCB) design, striving for the most homogeneous conditions as possible among plots in the same block. However, geostatistical concepts dictate that a spatial dependence exists for observations of a particular property, where closely spaced are more similar than those taken at a greater distance. The present study was conducted on an 18 ha lucerne (Medicago sativa) stand in which a 113 m X 145 m experimental area was demarcated. To determine spatial characteristics of soil and plant properties, 48 sampling points were selected using a 20 m square grid with an additional 75 points on a 2.5 m grid at five random node points. A RCB design trial was superimposed on the geostatistical grid design and consisted of seven pseudo (i.e. non-existent) treatments, replicated four times. Soil and plant samples were taken in June 2001 at all sampling points and plots and analyzed for various properties, including green biomass yield. Analysis of variance of the RCB design revealed statistically non-significant differences among the pseudo treatments, as expected, for various soil and plant properties, including yield. Although large yield differences (2.1 – 5.3 t ha- 1) were observed, the conclusion could be made that the experimental field was homogeneous enough to lay out a RCB design experiment. However, it was found that the estimate map of soil pH(H2O) indicated a spatial dependence. The question was posed that if spatial variation in soil pH(H2O) had been considered, would it have had any effect on the results of this field experiment, for example, in terms of yield? Scrutiny of the latter variability revealed that the standard RCB designs did not provide homogeneous blocks with respect to soil variability. The redesign of the experiment where all plots were randomly allocated to treatments and replications, led to significant differences obtained for plant and soil properties as a function of the pseudo treatments. Analysis of co-variance was then applied to eliminate variability between plots and the resultant pseudo treatments showed no significant differences. From this study it became evident that spatial variability of soil and plant properties can jeopardize the results of a standard RCB designed field experiment and should be taken cognizance of.

        Authors

        Venter, A., Smith, M.F., Beukes, D.J., Claassens, A.S. and Meirvenne, M. Van

        Year Published

        2009

        Publication

        South African Journal of Plant and Soil

        Locations
        DOI

        10.1080/02571862.2009.10639960

        This article contributed by:

        Original

        Relationships between soil buffer capacity and selected soil properties in a resource-poor farming area in the Mpumalanga Province of South AfricaBeukes, D.J.2009

        Relationships between soil buffer capacity and selected soil properties in a resource-poor farming area in the Mpumalanga Province of South Africa

        Keywords

        Potentiometric titration curves, principal component analysis, soil buffering capacity, yield

        Abstract

        Abstract In this study, the soil buffer capacity (soil BC) was measured for 80 topsoil samples of the most dominant soil forms in a small-scale farming area. Soils used in the study ranged from weakly to strongly buffered, with soil BC values ranging from 0.12 to 2.23 cmol (+) kg−1 pH unit−1. Relationships of soil BC over limited pH ranges showed that at soil BC(pHorganic C>clay. At soil BC(pH4.5–6.5) the buffering mechanism was extractable Al>clay>CBD-Al>organic C>CBD-Fe. The main buffering mechanism between pH 6.5–8.5 was clay>CBD-Fe, organic C>CBD-Al. At the general pH range of buffering (4.5-8.5), clay>organic C>extractable Al>CBD-Al>CBD-Fe were the main buffering mechanisms. The main soil forms, viz., Clovelly and Hutton, tended towards lower soil BC, extractable Al (or acidity) and acid saturation, and higher pH, extractable Ca and Mg values, compared to the Magwa and Inanda soil forms which had higher soil BC but lower extractable Al (or acidity), pH and extractable Ca and Mg levels. Clovelly soils tended to have lower clay, CBD-Fe and CBD-Mn contents than the Hutton soils in the study area.

        Authors

        Beukes, D.J., Claassens, A.S. and Jansen van Rensburg, H.G.

        Year Published

        2009

        Publication

        South African Journal of Plant and Soil

        Locations
        DOI

        10.1080/02571862.2009.10639961

        This article contributed by:

        Original

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