Small

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
Assessing the potential soil acidification risk under dryland agriculture in the Mlondozi district in the Mpumalanga Province of South AfricaBeukes, D.J.2009

Assessing the potential soil acidification risk under dryland agriculture in the Mlondozi district in the Mpumalanga Province of South Africa

Keywords

Acidification rates, acid production loads, buffer capacity, lime requirement

Abstract

Abstract The farming community in the Mlondozi district in the Mpumalanga Province of South Africa has been part of a government liming intervention with the objective to ameliorate the serious soil acidity problem in the district. The current study was undertaken in order to evaluate the impact of the liming intervention and the risk of re-acidification of the soil due to natural and agricultural activities. Acid production in the 0-250 mm depth varied from a measured 0.21 to 10.31 (mean 3.70 kmol H+ ha- 1 year- 1) in crop production sites. Approximately 190 kg lime ha- 1 yr- 1 is required to maintain current soil pH levels under crop production. The rate of pH decline for the top 0-250 mm depth was between 0.051 and 0.918 (mean 0.237) pH units year- 1. In the absence of remedial lime applications, pH(H2O) values in most of the area are projected to decrease to the critical value of 5.68 or lower within 4 years. The upper and lower critical pH(H2O) were found to be between ca. 5.73 and 5.68. Below the lower critical value a reduction in crop production can be expected and above the upper critical value, accelerated acidification takes place. Soils with an extractable Al and acidity of <0.253 cmol (+) kg−1 soil, respectively, a clay content of 26%, and an ECEC value of 3.29 cmol (+) kg soil−1, or high initial soil pH values, are more at risk to accelerated acidification than soils with lower extractable Al and acidity, higher clay contents and higher ECEC values.

Authors

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

Year Published

2009

Publication

South African Journal of Plant and Soil

Locations
DOI

10.1080/02571862.2009.10639962

This article contributed by:

Original

The effect of the adjuvant, Break-Thru S240, on whorl penetration and efficacy of foliar insecticide applications against Chilo partellusSlabbert, O.2009

The effect of the adjuvant, Break-Thru S240, on whorl penetration and efficacy of foliar insecticide applications against Chilo partellus

Keywords

Chemical control, organo-trisiloxane, stem borer

Abstract

Abstract Insecticide sprays registered for the control of maize stem borers are all intended for whorl application. Chemical control of these pests is complicated by their cryptic feeding habit inside plant whorls. The aim of this study was to investigate whether addition of the organosilicone adjuvant, Break-Thru S240, to insecticide sprays would result in improved stem borer control. In one experiment the position of stem borer feeding damage inside plant whorls was quantified to have a standard for comparison and evaluation of the effective distances of downwards movement of spray applications into whorls. The distance of movement of spray applications at five adjuvant rates (50, 100, 200, 400 & 600 ml ha−1) into whorl leaves was determined. A colorant was added to spray applications to facilitate measuring the distances of downwards movement of water into each whorl leaf. A 14% increase in downwards movement of sprays into the target zone was observed with addition of the adjuvant. Efficacy of insecticide sprays for control of C. partellus with and without the adjuvant was evaluated under field conditions. Increased levels of efficacy were observed with addition of the adjuvant but not with all the insecticides.

Authors

Slabbert, O. and den Berg, J. Van

Year Published

2009

Publication

South African Journal of Plant and Soil

Locations
    DOI

    10.1080/02571862.2009.10639963

    This article contributed by:

    Original

    Evaluation of near infrared spectra for the prediction of post harvest quality in canning peachesManley, M.2009

    Evaluation of near infrared spectra for the prediction of post harvest quality in canning peaches

    Keywords

    MARS, near infrared spectroscopy, peaches, post-storage quality, SIMCA

    Abstract

    Abstract Huge production losses occur because of deterioration of quality of clingstone peaches during cold storage, rendering the fruit unsuitable for canning. Near infrared (NIR) spectra recorded from intact clingstone peaches were evaluated to predict post harvest quality of these peaches. The NIR spectra were recorded, before storage, on the fresh peaches while the subjective post-storage quality, fruit firmness and diameter (reference data) were determined after either three- (2002 season) or two-week (2003 season) cold storage periods at -0.5ºC. Poor post-storage quality was indicated by softening of the flesh, loosening of the skin and adhesion of the flesh to the stone after destoning. Soft independent modeling by class analogy (SIMCA) gave correct total classifications of between 53 and 60% in comparison to the 57 to 65% obtained by multivariate adaptive regression splines (MARS). However, when predicting only poor post-storage quality, correct classfication rates of between 60 and 80% were obtained using MARS. Using classification trees, the fruit were classified into good and poor post-storage quality classes according to fruit firmness and diameter. Only reasonable results were obtained due to the poor relationship between the NIR spectra and firmness measurements.

    Authors

    Manley, M., Joubert, E., Myburgh, L., Lotz, L. and Kidd, M.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639946

    This article contributed by:

    Original

    Morpho-physiological response of durum wheat genotypes to drought stressSolomon, K.F.2009

    Morpho-physiological response of durum wheat genotypes to drought stress

    Keywords

    Drought stress, net assimilation rate, relative growth rate, phenology

    Abstract

    Abstract The impact of moisture stress on phenology and growth varies for genotypes and the growth stages at which stress is encountered. The aim of this study was to determine the effect of moisture stress on some morpho-physiological traits of durum wheat genotypes under optimum and stress moisture conditions. Genotypes differing in their responses to moisture stress were grown under differing water regimes, one at 70% and the other at 35% available soil moisture. Differences in days to heading, anthesis and physiological maturity were highly significant among genotypes at the two moisture levels. Drought stress delayed the major growth stages. Although this was not expected, it has been reported previously in durum wheat. Variability in relative growth rate, components of relative growth rate, net assimilation rate and leaf area ratio was significant. Drought tolerant genotypes had fast early growth. Variation in relative growth rate was associated with both the net assimilation rate and leaf area ratio. The variation in leaf area ratio under control conditions was both due to specific leaf area and leaf weight ratio. However, under stress conditions, ability to maintain higher leaf area ratio was mainly due to higher specific leaf area.

    Authors

    Solomon, K.F. and Labuschagne, M.T.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639947

    This article contributed by:

    Original

    Relationships between soil particle size fractions and infiltrabilityMedinski, T.V.2009

    Relationships between soil particle size fractions and infiltrability

    Keywords

    Dispersion, particle size distribution, soil crusting

    Abstract

    Abstract The influence of particle size fractions on infiltrability was investigated in soils sampled across Namibia and western South Africa. Infiltrability was determined using a laboratory technique calibrated with rainfall simulation, which measures the passage of a suspension of soil particles through a packed soil column. Water-dis-persible soil particle size fractions were determined using a high definition digital laser particle size analyser. Total (calgon-dispersed) particle size fractions were determined by hydrometer. Dispersion of soil particles resulting in crust formation on the soil surface appeared to be a main mechanism reducing infiltrability. Water-dispersible clay and fine silt determined by laser analyser showed higher correlation with infiltrability (r2 = −0.43 for clay and −0.47 for fine silt) than total clay and fine silt determined by hydrometer (r2 = −0.30 and −0.28, respectively). Clay, fine silt, coarse silt, very fine sand and fine sand fractions ( 5% infiltrability was inevitably restrained. The 120–200 µm fraction showed no clear relationship with infiltrability. It played either a plasmic or skeletal role, depending on its ratio to the 200 µm fractions. Fine, medium and coarse sand fractions (>200 µm) showed a probable skeletal role in soil crusts, i.e. forming pores that enhanced infiltrability. At levels >50% of these fractions, infiltrability was potentially maximal. This potentially maximal infiltrability was also explained by the concomitant decrease in plasmic fraction content with an increase of the skeletal fraction.

    Authors

    Medinski, T.V., Mills, A.J. and Fey, M.V.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639948

    This article contributed by:

    Original

    Infiltrability in soils from south-western Africa: effects of texture, electrical conductivity and exchangeable sodium percentageMedinski, T.V.2009

    Infiltrability in soils from south-western Africa: effects of texture, electrical conductivity and exchangeable sodium percentage

    Keywords

    Electrical conductivity, ESP, gypsum, particle size distribution, soil crusting

    Abstract

    Abstract The effects of particle size, electrical conductivity (EC) and exchangeable sodium percentage (ESP) on infiltra-bility were investigated in 35 soils from Namibia and western South Africa. Samples were grouped as follows: sand (5–9% clay + silt), loamy sand (16–20%) and silty loam (73–80%). Subgroups included: low EC and low ESP (LL); low EC and high ESP (LH) and high EC and ESP (HH). Infiltrability was measured using a rapid laboratory syringe method. To investigate dispersion and flocculation processes the effect of four mobile phases on infiltrability was examined. Mobile phases included distilled water (W), a gypsum solution (G), a 1:5 soil suspension in gypsum solution (GS), and a 1:5 soil suspension in water (WS). Infiltrability was highest in the sand group, and lowest in the silty loam group. Electrical conductivity and ESP effects varied between particle size groups. In the silty loam group, EC and ESP effects were not significant due to swelling of clay minerals and rapid blockage of soil pores with dispersed particles. In the sand group, soils with high ESP (22) had significantly lower (p<0.05) infiltrability than soils with low ESP (4) levels. The application of gypsum in these soils enhanced infiltrability and minimized the negative effect of high ESP. The ameliorating effect of gypsum was apparent in treatment GS, but not treatment G, which highlights the dominant effects of mechanical disturbance and clay dispersion on crust formation and infiltrability.

    Authors

    Medinski, T.V., Mills, A.J. and Fey, M.V.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639949

    This article contributed by:

    Original

    Grain yield and rainfall use efficiency responses of maize and alternative rotating crops under marginal production conditions in the western Highveld of South AfricaNel, A.A.2009

    Grain yield and rainfall use efficiency responses of maize and alternative rotating crops under marginal production conditions in the western Highveld of South Africa

    Keywords

    Cowpea, fallow, groundnut, soyabean, sunflower

    Abstract

    Abstract Crop rotation is known to enhance crop yields. It is therefore recommended, regardless of rainfall and soil type, as a counter measure for the risks associated with monoculture maize (Zea mays). Experience in the western Highveld where rainfall is low and erratic, has shown that the yield of maize does not necessarily improve as expected when preceded by alternative crops, but in fact, is often reduced. The present study was initiated to determine the effect of crop rotation with cowpea, groundnut, soyabean, sunflower or fallow on the yield and rainfall use efficiency of maize under marginal conditions on the western Highveld. Dryland maize was grown in five crop rotation systems on Hutton type soils at the farms Holfontein (four years) and Noodshulp (five years), both situated close to Ottosdal (26° 49’ S; 26° 00’ E). The soil profiles had an effective depth of <1.5 m at Hol-fontein and 1.25 m at Noodshulp. Crop rotation systems consisted of two-year rotations of cowpea-, groundnut, soybean-, sunflower-, and fallow-maize; as well as groundnut-, soybean-, and sunflower-fallow. A continuous monoculture maize treatment was included to serve as control. At Noodshulp where the rainfall was more variable, crop rotation induced maize yield deviations from the monoculture control occurred more often than at Holfontein. Apart from yield neutral and positive effects, instances of a decline in maize yield in some years due to crop rotation with cowpea, groundnut and sunflower also occurred. Taking the long-term rotational effect and the possibility of a yield decline into account, fallowing and the rotational crops ranked from best to worse were groundnut, soyabean, fallowing, cowpea and sunflower. The long-term effect of cowpea on the yield of maize was neutral and that of sunflower negative. The mean rainfall use efficiency of monoculture maize was, with the exception of maize preceded by groundnut, similar to that of maize grown in rotation.

    Authors

    Nel, A.A.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639950

    This article contributed by:

    Original

    Soil water variability in the Weatherley grassland catchment, South Africa: I. EvapotranspirationHuyssteen, CW van2009

    Soil water variability in the Weatherley grassland catchment, South Africa: I. Evapotranspiration

    Keywords

    crop coefficient, evapotranspiration, grassland catchment, soil water balance, water stress

    Abstract

    Abstract Evapotranspiration (ET) is a major component of the soil water balance and therefore requires accurate determination to quantify catchment water yield. Six-year daily ET was determined at 300 mm depth intervals in the root zone of 28 soil profiles in the Weatherley catchment in South Africa. Daily ET was calculated based on the soil water balance equation and interpretation of the physical and morphological properties of the soils. Water losses by ET were studied at various soil water contents. This established the ET/ET0 for veld grass and therefore enabled the calculation of daily ET from daily ET0. Resulting annual mean daily ET ranged from 1.4 mm d- 1 (50% of rainfall) at the driest hillslope site to 2.6 mm d- 1 (90% of rainfall) at the marsh. Results indicated that the proposed procedure enabled fairly accurate determination of ET for the grassland catchment.

    Authors

    Huyssteen, CW van, Zere, TB and Hensley, M

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639951

    This article contributed by:

    Original

    Soil water variability in the Weatherley grassland catchment, South Africa: II. Soil water contentZere, TB2009

    Soil water variability in the Weatherley grassland catchment, South Africa: II. Soil water content

    Keywords

    Hydropedology, model, soil water, water saturation

    Abstract

    Abstract Soil 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 calculated based on weekly measured and other data for the Weatherley grassland catchment in South Africa. A modelling procedure, based on the soil water balance equation and the interpretation of the physical properties of soils was used to calculate daily θ for all 28 sites for the six-year period. A statistical model performance indicated that the mean index of agreement was 0.88, root mean square error (RMSE) was 6.8 mm water per 300 mm soil and mean unsystematic RMSE to total RMSE was 93%. These results indicated that the calculated soil water contents agreed well with the measured values and could therefore be used with reasonable confidence to fill data gaps. The proposed procedure therefore affords the possibility to increase the resolution of irregular measured soil water content data. This would significantly advance the usability of such data, because the influence of rainfall events on soil water content is frequently missed by manual soil water content measurements.

    Authors

    Zere, TB, Hensley, M and Huyssteen, CW van

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639952

    This article contributed by:

    Original

    FAO-type crop factor determination for irrigation scheduling of hot pepper (Capsicum annuum L.) cultivarsAnnandale, J.G.2009

    FAO-type crop factor determination for irrigation scheduling of hot pepper (Capsicum annuum L.) cultivars

    Keywords

    basal crop coefficient, crop coefficient, crop evapotranspiration, crop model, SWB model

    Abstract

    Abstract Hot pepper (Capsicum annuum L.) is an irrigated, high value cash crop. Irrigation requirements can be estimated following a FAO crop factor approach, using information on basal crop coefficients (Kcb), crop coefficients (Kc) and duration of crop growth stages. However, this information is lacking for hot pepper cultivars differing in growth habit and length of growing season under South African conditions. Detailed weather, soil and crop data were collected from three field trials conducted in the 2004/05 growing season. A canopy-cover based procedure was used to determine FAO Kcb values and growth periods for different growth stages. A simple soil water balance equation was used to estimate the ETc and Kc values of cultivar Long Slim. In addition, initial and maximum rooting depth and plant heights were determined. A database was generated containing Kcb and Kc values, growing period duration, rooting depth, and crop height for different hot pepper cultivars, from which the seasonal water requirements were determined. The length of different growth stages and the corresponding Kcb values were cultivar and growing condition dependent. The database can be used to estimate Kcb and Kc values for new hot pepper cultivars from canopy characteristics. The Soil Water Balance (SWB) model predicted the soil water deficits to field capacity and fractional canopy cover well, using the FAO crop factor approach.

    Authors

    Annandale, J.G., Steyn, J.M. and Alemayehu, Y.A.

    Year Published

    2009

    Publication

    South African Journal of Plant and Soil

    Locations
    DOI

    10.1080/02571862.2009.10639953

    This article contributed by:

    Original

    Recent Articles

    Perspectives on the Principles and Structure of the Soil Classification System in South Africa: Discussion and Practical Examples

    by Turner, David P

    The paper discusses revised principles, perspectives and structure for soil classification of natural soils in South Africa. An expanded ‘sphere of pedological interest’ is proposed through the formal recognition of a wider range of subsurface soil materials. The concept of soil groups has been recognised and is further developed as a formal classification category. In addition, a subgroup cate...

    published 2013 in South African Journal of Plant and Soil

    Phytochemical Content, Antioxidant Capacity and Physicochemical Properties of Pomegranate Grown in Different Microclimates in South Africa

    by Mditshwa, Asanda, Fawole, Olaniyi A, Al-Said, Fahad, Al-Yahyai, Rashid and Opara, Umezuruike L

    We investigated the antioxidant and physicochemical properties of pomegranate (Punica granatum cv. Bhagwa) fruit grown in three microclimates in South Africa. The physicochemical properties of fruit peel and arils differed among the growing locations, including weight and redness color of both peel and arils. Contents of vitamin C, anthocyanin and total phenolics were 0.67–1.41 mg ml−1, 0.07–0....

    published 2013 in South African Journal of Plant and Soil


    Estimation of Thrips (fulmekiola Serrata Kobus) Density in Sugarcane Using Leaf-Level Hyperspectral Data

    by Abdel-Rahman, Elfatih M, Way, Mike, Ahmed, Fethi, Ismail, Riyad and Adam, Elhadi

    The aim of this study was to investigate the potential use of leaf-level hyperspectral data to predict the density of sugarcane thrips Fulmekiola serrata (Kobus). A hand-held spectroradiometer was used to make the spectral measurements on spindle leaves of 4- to 5-month-old plants of sugarcane cv. N19 growing in commercial fields near Umfolozi, South Africa. A random forest algorithm followed b...

    published 2013 in South African Journal of Plant and Soil

    A Revised Perspective on Principles of Soil Classification in South Africa

    by Turner, David P

    Limited significance has been given to the formal recognition of certain subsoil materials in the South African Soil Classification System. Three principles in the current classification system are discussed using variants of soil profiles associated with the Avalon soil form. The retention of the arbitrary depth criterion is questioned in favour of the recognition of an enlarged ‘sphere of ped...

    published 2013 in South African Journal of Plant and Soil