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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
Effects of liming on microbial activity and N mineralization in broiler manure-amended soils from Bizana, Eastern Cape, South AfricaAverbeke, W. van2009

Effects of liming on microbial activity and N mineralization in broiler manure-amended soils from Bizana, Eastern Cape, South Africa

Keywords

Biological activity, chicken manure, lime, nitrogen mineralization, soil acidity

Abstract

A laboratory incubation study was conducted to determine the effects of liming on microbial activity and N mineralization in two Bizana soils amended with broiler manure. The experimental layout was a 4 x 3 complete factorial experiment with three replicates, arranged in a randomized design. Soil pH, CO2 evolution, and mineral N concentration were measured. After 56 days the soil pH ranged from 4.50 to 5.74 and 4.99 to 5.94, in the Magusheni and Nikwe soils, respectively. The effect of liming on microbial activity and N mineralization differed between the soils. In the Nikwe soil (acid saturation 4.0%), microbial activity and N mineralization increased as the rate of broiler manure application was raised, but liming had no effect. In the Magusheni soil (acid saturation 25%), microbial activity increased as both lime and chicken manure application rates increased, but liming reduced N mineralization, suggesting N immobilization was being driven by an active microbial population in the limed soils. The rates of lime and/or chicken manure application, percentage Ca2 + and soil acid saturation were important factors influencing microbial activity and N mineralization, but the effect of soil pH on N mineralization was not evident in either of the soils.

Authors

Averbeke, W. van, Jezile, G.G., Westfall, D.G., Peterson, G., Child, D.R. and Turner, D.P.

Year Published

2009

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2009.10639927

This article contributed by:

Original

Grain yield response and Chilo partellus infestation in diverse sorghum-cowpea intercrop arrangementsAyisi, K. K.2001

Grain yield response and Chilo partellus infestation in diverse sorghum-cowpea intercrop arrangements

Keywords

Chilo partellus, cowpea, intercropping, sorghum

Abstract

Yield improvement and insect pest control in intercropping systems relative to sole cultures has been variable and inconsistent over habitats, component species, varieties, density, row arrangement, soil fertility and moisture. This study was initiated to quantify yield response of two sorghum varieties (Macia and SV-2) and a cowpea variety, PAN311 to different crop arrangements and to assess the level of Chilo partellus infestation in sorghum in the intercropping system. Superior intercropped sorghum yield was obtained when component crops were arranged in alternate rows at a 0.90 m spacing whereas cow- pea yields were similar to or lower than sole crop yield in the different component crop arrangements. The overall land use efficiency, assessed by the land equivalent ratio (LER), was improved by an average of 11% with intercropping at a row spacing of 0.90 m. However, no yield benefit was observed when crops were arranged in an alternate row pattern at a narrow row spacing of 0.45 m. Intercropping reduced C. partellus infestation in mixed and alternate intercropping systems, relative to the sole cultures.

Authors

Ayisi, K. K., Mposi, M. S. and Van den Berg, J.

Year Published

2001

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2001.10634399

This article contributed by:

Original

Grain yield and contribution of symbiotically fixed nitrogen to seed in cowpea varieties using the 15N natural abundance techniqueAyisi, K. K.2000

Grain yield and contribution of symbiotically fixed nitrogen to seed in cowpea varieties using the 15N natural abundance technique

Keywords

Cowpea, grain yield, natural abundance, variety, yield component

Abstract

Identification of cowpea varieties with superior grain yield and high nitrogen fixing potential is crucial to increasing productivity of the crop among small-scale farmers in the Northern Province. A field experiment was established during the 1997/98 growing season to evaluate six cowpea varieties for their grain yield, protein content, yield components and proportion of seed N derived from symbiotic fixation (%Ndfa) through the natural abundance technique. The varieties evaluated were PAN311, Glenda, Bechauana white, Chappy, Encore and NWK. PAN311 produced the highest grain yield of 1635 kg ha−1 which was 90% higher than the average across varieties. The lowest yielding variety was Glenda with an average of 368 kg ha−1. The high grain yield of PAN311 could be attributed to its high number of pods per plant, seed mass as well as harvest index. Seed protein concentration ranged from 237–275 g kg−1 but did not differ among the varieties. Estimates of %Ndfa in seed ranged from 23.02–28.80% with Bechuana white showing the highest dependance and PAN311 the least. PAN311 is clearly the highest grain yielding variety, though several of the other varieties have the potential of improving farmers yield which is estimated to be about 400 kg ha−1.

Authors

Ayisi, K. K.

Year Published

2000

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2000.10634889

This article contributed by:

Original

Fitting underutilised crops within research-poor environments: Lessons and approachesAzam-Ali, S.N.2010

Fitting underutilised crops within research-poor environments: Lessons and approaches

Keywords

Bambara, biodiversity, transdisciplinary, underutilised

Abstract

Underutilised crops, the cropping systems in which they are cultivated and the people who manage, protect and conserve them represent important elements of agricultural biodiversity. Each of these components and our knowledge of them is increasingly marginalised by the structures and rewards of modern agricultural research. The ‘silofication’ of research into rigid disciplines, the incentives for fundamental research on major crops and the preference for short-term research on simple cropping systems all mitigate against progress on agricultural biodiversity, in general, and underutilised crops, in particular. This paper considers the lessons that can be learned from current research projects on one underutilised crop – bambara groundnut – and argues that new ‘trans-disciplinary’ approaches are necessary for future progress.

Authors

Azam-Ali, S.N.

Year Published

2010

Publication

South African Journal of Plant and Soil

Locations
    DOI

    10.1080/02571862.2010.10639997

    This article contributed by:

    Original

    Underutilised indigenous and traditional crops: why is research on water use important for South Africa?Backeberg, G.R.2010

    Underutilised indigenous and traditional crops: why is research on water use important for South Africa?

    Keywords

    Drought stress, indigenous crops, research, traditional crops, water use

    Abstract

    The answer to the question ‘why is research on water use important for South Africa?’ is quite straightforward: more research is needed because there is a major gap in knowledge on water use of indigenous crops. These indigenous edible plants have sustained rural populations in developing countries for many decades if not centuries. Traditional crops are native to specific localities, are therefore better adapted to the environmental conditions and can be cultivated without the need for expensive inputs such as irrigation water and agri-chemicals (Water Research Commission, 2008). This must be seen in the context of the fact that the biggest share of water is used for farming, while at least 15 million people in rural areas of South Africa live below the poverty line. In the Research and Development Strategy for Water Utilisation in Agriculture (Water Research Commission, 2008) it is therefore stated that two relevant objectives are to (1) increase biological, technical and economic efficiency of water use; and (2) reduce poverty through water-based agricultural activities. Although farming makes a relative small contribution (7 – 12%) to income for livelihoods of the rural poor population (Van Aver-beke, 2008), there are many unutilised opportunities for production and earning of income, particularly from indigenous crops. Agriculture (farming and agri-processing activities) is therefore the key to rural development, but this requires that water use and production must be analysed as a value adding process in the food value chain (Backeberg & Sanewe, 2006).

    Authors

    Backeberg, G.R. and Water, A.J. Sanewe

    Year Published

    2010

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2010.10639996

    This article contributed by:

    Original

    Improving the isolation of actinomycetes from soil by high-speed homogenizationBaecker, A. A.W.1987

    Improving the isolation of actinomycetes from soil by high-speed homogenization

    Keywords

    Actinomycetes, comminution, high-speed liquid homogenization, soils

    Abstract

    Quantitative isolation of actinomycetes from five South African soils with different physical and chemical properties was conducted by hammer-mill comminution followed by high-speed liquid homogenization of resultant soil particles using a shaft homogenizer. Soil homogenates were serially diluted and plated in starch-casein agar and chitin agar for enumeration of isolates. For comparative purposes isolations were also conducted using conventional soil dilution techniques. The results were analysed using a GENSTAT computer program. Analysis showed that homogenization consistently suspended significantly greater numbers of spores from soil particles. Significant differences between magnitudes of actinomycete populations in different soils were also observed. During the initial standardization of the homogenization period required to separate maximum numbers of spores from the soil particles it was found that rates of suspension differed among soils and it is suggested that the particle size distribution and cation exchange capacity in each soil contributed to these differences. Significant differences in the numbers of actinomycetes isolated from different soils were attributed to the amount and nature of the carbon fraction in each soil. It is suggested that comminution, homogenization and dilution plating with appropriate selective culture media could be used to enumerate actinomycetes and other micro-organisms in various substrates not amenable to conventional dilution plating provided the degree of homogenization used is standardized for each new application of the technique.

    Authors

    Baecker, A. A.W. and Ryan, K. C.

    Year Published

    1987

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1987.10634967

    This article contributed by:

    Original

    Comparative patterns of sodium accumulation in leaves of selected savanna species growing on sodic and nonsodic soilsBailey, Catherine L.1997

    Comparative patterns of sodium accumulation in leaves of selected savanna species growing on sodic and nonsodic soils

    Keywords

    Exclusion mechanisms, foliar nutrient levels, herbivores, sodic soil, sodium

    Abstract

    Plants show differing mechanisms of tolerance to high sodium levels in soils. Physiological and biochemical mechanisms have been investigated for many crop species but little information is available for indigenous tree and grass species. Foliar concentrations of sodium, calcium, potassium, magnesium and nitrogen were measured in selected savanna species growing on and off sodic soils. Sodic soils are those defined as having a high exchangeable sodium percentage or a high sodium adsorption ratio. Sodium concentrations of up to 6% were measured in the leaf tissue of species found growing solely on sodic sites. Species that grow both on and off sodic sites did not show significantly different levels of foliar nutrients although the levels of exchangeable soil cations were quite different on the two sites. The data suggest that plants which grow specifically on sodic soils have inclusion mechanisms which allow for high levels of sodium in the leaf tissue which do not disrupt physiological functioning whereas other species have the ability to exclude sodium either at the root membrane level or by sequestration in the root tissue. In all cases there was an inverse relationship between calcium and sodium levels in the tissue suggesting competitive uptake. Although sodic-soil sites have low vegetation cover, herbivores tend to congregate at these sites. It is suggested that sodium, magnesium and potassium in the leaves are influential in attracting herbivores to sodic-soil sites.

    Authors

    Bailey, Catherine L. and Scholes, Mary C.

    Year Published

    1997

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1997.10635090

    This article contributed by:

    Original

    Phosphorus sorption in Natal soilsBainbridge, S. H.1995

    Phosphorus sorption in Natal soils

    Keywords

    Isotherms, near infra-red reflectance spectroscopy, organic matter, phosphorus sorption

    Abstract

    Phosphorus (P) sorption poses a severe constraint on the ability of many soils to supply adequate amounts of P to plants. In an effort to quantify the P sorption capacities of soils in Natal, P sorption isotherms of 50 topsoils from a number of localities in the province were established. The amount of P sorbed at a solution P level of 0.2 mg P L−1, defined as the standard P requirement, varied from 5 to 1174 mg kg−1. Standard P requirement was greatest in highly weathered clay soils and lowest in sands. Various soil parameters were correlated with standard P requirement and isotherm slope at 0.2 mg P L−1. Oxalate-extractable aluminium, organic matter and sample density gave the best correlations. Because the method for the determination of sorption isotherms is tedious and does not lend itself to routine use, the feasibility of predicting the isotherm slope by near infra-red reflectance spectroscopy was also investigated. Preliminary results were encouraging and a calibration based on the samples used in this study yielded an r 2 of 0.82 and a residual standard deviation of 184.

    Authors

    Bainbridge, S. H., Miles, N., Praan, R. and Johnston, M. A.

    Year Published

    1995

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.1995.10634338

    This article contributed by:

    Original

    The effect of poor quality seed and various levels of grading factors on the germination, emergence and yield of wheatBarnard, A.2011

    The effect of poor quality seed and various levels of grading factors on the germination, emergence and yield of wheat

    Keywords

    Falling number, hectoliter mass, preharvest sprouting, protein content

    Abstract

    Abstract High quality seed is essential for establishing productive stands of wheat. Seed should have, amongst others, a high germination percentage, be free of seed borne diseases and should not contain any weed seed. Protein content (PC), hectolitre mass (HLM) and falling nudmber (FN) are three important quality characteristics determining the grading of wheat at delivery point. Seed with high and low values of these three quality requirements were planted over a two year period under dryland and irrigation conditions to determine the effect of these quality parameters on the yield of the following crop. Seed with various levels of preharvest sprouting damage were also planted to determine the effect of sprouting on the field performance of the crop. Results from this study showed that germination was not affected by grading factors, but the emergence of seed with low HLM was significantly reduced compared to high HLM seed. Low PC had a significant effect on the crop, especially under dryland conditions, while FN did not have an effect. Severely sprouted seed had a significant negative effect on the emergence and yield, especially when seeds were carried over to the next planting season. However, a low intensity of sprouting did not affect the yield negatively. End results indicated that using low quality seed for planting can have a negative effect on crop yield. It is concluded that producers should use certified seed that is true to variety, is clean and has a high germination percentage for crop production.

    Authors

    Barnard, A. and Calitz, F.J.

    Year Published

    2011

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2011.10640009

    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

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