| Growth and production of Vicia dasycarpa Ten., Namoi as influenced by an oat support crop and nitrogen fertilizer | Wassermann, V. D. | 1984 |
KeywordsNitrogen, oats, support crop, Vicia dasycarpa AbstractThe performance of Vicia dasycarpa cv. Namoi in pure stand and mixed with oats at four densities, grown at three levels of N fertilizer, was studied in the field under irrigation. Both the increased plant density of oats and N fertilizer reduced the percentage vetch in the mixtures. However, the percentage vetch in all mixtures increased as the growing season progressed. Compared to pure vetch, admixing oats increased total yields significantly, and the mixtures also responded positively to N application. On the other hand, the different treatments did not differ significantly in total crude protein production. It was concluded that Namoi is an excellent legume for combining with oats for high yields of good quality fodder. S. Ah. J. Plant Soil 1984, 1: 79–82 AuthorsWassermann, V. D., Heyns, Gillian and Kruger, A. J. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634114 This article contributed by:
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| Assessment of aluminium tolerance in maize using a rapid screening procedure | Mendes, Paula | 1984 |
KeywordsAluminium tolerance, maize cultivars AbstractRoutine testing for Al tolerance requires that screening procedures be both rapid and simple. Growth-chamber techniques, developed in the USA, show considerable promise in this regard and were used in this study to compare the Al tolerance of 10 maize cultivars and to test the reliability of several plant performance indices proposed in the literature. Seedlings were grown under controlled environmental conditions in complete nutrient solutions, with and without Al. Visual assessment of roots grown in the presence of Al facilitated separation of the cultivars into three groups. RS5205, SR52, CG4801 and PNR394 were classed as ‘good’; SSM2039, SNK2147, and SABI308 as ‘intermediate’; and A475W, RO422 and TX390 as ‘poor’. Visual assessments, total root length measurements and indices obtained using the primary seminal root provided measures of Al tolerance in good agreement with field performance. Topgrowth and root mass were poorly related to plant performance and relative indices obtained using root measurements in the presence and absence of Al were markedly inferior to indices obtained from Al solutions alone. The suggestion is made that screening could possibly be successfully performed using visual root ratings. Inclusion of standard genotypes would eliminate much of the subjectivity associated with such procedures. S. Afr. J. Plant Soil 1984, 1: 83–86 AuthorsMendes, Paula, Farina, M.
P.W. and Channon, P. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634115 This article contributed by:
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| Effect of moisture supply on CAM in Opuntia aurantiaca (jointed cactus) | Whiting, B. H. | 1984 |
KeywordsCAM, gas exchange, jointed cactus, moisture stress, Opuntia aurantiaca AbstractThe patterns of gas exchange exhibited by Opuntia aurantiaca under controlled conditions (photoperiod 12 h; day/night temperature regime 30/15°C) were investigated for plants subjected to various levels of moisture stress. Unstressed plants exhibited a typical full-CAM pattern of gas exchange in which all four phases of CAM-linked CO2 exchange were evident. Net CO2 uptake during phase 1 contributed up to 82% of total carbon fixed per 24 h. The transpiration: photosynthesis ratio was low (night 31; day 135), within the range exhibited by many CAM plants and indicative of a high water use efficiency. Under all conditions of water stress net carbon gain was reduced with phase IV showing the greatest reduction and phase 1 the least. On watering, stressed plants recovered rapidly. Within 48 h of receiving water total CO2 uptake per 24 h had risen from 5,8% to 76,5% of the unstressed value. S. Afr. J. Plant Soil 1984, 1: 87–91 AuthorsWhiting, B. H. and Campbell, E. E. Year Published1984 PublicationSouth African Journal of Plant and Soil Locations- field site near Uitenhage (-33.7637, 25.3936)
- Leeudoringstad, Northwest (-27.2333, 26.2333)
- Viljoenskroon, Freestate (-27.2167, 26.95)
- Sannieshof, Northwest (-26.5333, 25.8)
- Roodeplaat, Gauteng (-25.604, 28.345)
- Tovoomba, Limpopo (-24.8833, 28.2833)
- Standerton, Mpumalanga (-26.95, 29.25)
DOI10.1080/02571862.1984.10634116 This article contributed by:
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| Seisoensveranderinge in die koolhidraatinhoud van jong appelbome | Stassen, P.
J.C. | 1984 |
KeywordsApple trees, carbohydrates, hemicellulose, starch, sugar AbstractGereelde ontledings van die koolhidraatfraksies in jong appelbome het getoon dat suiker 'n relatief klein gedeelte van die koolhidrate in die boomdele uitmaak, en veral in die wortels voorkom. Stysel akkumuleer in die wortels tot finale blaarval in die winter, waarna 'n afname in styselinhoud begin, en voortduur tot ongeveer sewe weke na bottyd. Hemisellulose kom in groot hoeveelhede in die houtweefsel voor waar dit hoofsaaklik struktureel van aard is. Dit wil voorkom asof hemisellulose gedurende die herfs in die wortelweefsel gemobiliseer word, moontlik om aktiefgroeiende haarwortels te onderhou. S.-Afr. Tydskr. Plant Grond 1984, 1: 92–95 AuthorsStassen, P.
J.C. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634117 This article contributed by:
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| Effect of soil fertility on the vegetative growth, yield and water use of wheat (Triticum aestivum L.) | Annandale, J. G. | 1984 |
KeywordsLeaf area duration, soil fertility, Triticum aestivum(L.), water-use efficiency, wheat AbstractWell-fertilized wheat was found to use more water than wheat on poorly fertilized plots, but the yield was increased, resulting in increased water-use efficiency. Variations in leaf area duration after anthesis accounted for 81% of the variation in yield. AuthorsAnnandale, J. G., Hammes, P. S. and Nel, P. C. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634118 This article contributed by:
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| Effect of the amount of surface maize residue on infiltration and soil loss from a clay loam soil | Lang, P. M. | 1984 |
KeywordsErosion, infiltration, maize residue, mulch, rainfall simulator, soil loss AbstractSix levels of maize stover, expressed as percentage ground cover (0–75%) were compared under a rainfall simulator to assess the effect of surface residues on infiltration and soil loss on a clay loam soil with a 3,5% slope. Increasing the percentage ground cover resulted in increased infiltration and was even more effective in controlling soil loss. Under the experimental conditions a minimum residue ground cover of 30% was required to keep runoff and soil loss within acceptable limits. AuthorsLang, P. M. and Mallett, J. B. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634119 This article contributed by:
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| Relationship between cation exchange capacity, clay content and water retention of Highveld soils | Lambooy, Astrid M. | 1984 |
KeywordsWater retention, cation exchange capacity, clay content AbstractWater in the soil is held by capillary and adsorption forces. These forces are mainly a function of clay content and mineralogy. To neglect the influence of clay mineralogy when estimating the water-holding properties of soil, implies that only a part of these forces is considered. It is convenient to use some easily measurable soil property to quantify the effect of clay mineralogy, In this study cation exchange capacity (CEC) was used for this purpose. For 320 soil samples of the Highveld Region, water content at a matrix potential of - 33 kPa, −1 500 kPa and the percentage water retained between −33 kPa and - 1500 kPa (ΔW), were compared with different parameters. The water retentivity of disturbed soils can be predicted more accurately if variations in CEC are taken into account. Highly significant multiple correlation coefficients of 0, 97, 0, 96 and 0, 91 respectively, were calculated for the relationships of CEC (me/100 g soil) and clay content with water content at −33 kPa and - 1 500 kPa and with ΔW. S. Afr. J. Plant Soil 1984, 1: 33–38 AuthorsLambooy, Astrid M. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634106 This article contributed by:
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| Soil factors affecting tree growth and root development in a citrus orchard | Nel, D. J. | 1984 |
KeywordsCitrus, tree growth, root development, soil characteristics, porosity, air capacity AbstractTree- and root-growth parameters correlated well with a number of soil properties Useful relationships were established between unconfined penetrometer resistance, air capacity (at FWC), tree growth and root development. Tree and root growth were also restricted in the soil where the long-term air-filled porosity was almost continuously less than 15%. S. Afr. J. Plant Soil 1984, 1: 39–47 AuthorsNel, D. J. and Bennie, A.
T.P. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634107 This article contributed by:
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| A complex dormancy mechanism in seeds of the weed Rubus cuneifolius | van Staden, J. | 1984 |
KeywordsRubus cuneifolius, germination, dormancy, scarification, stratification AbstractBoth the endocarp and embryo contribute to the dormancy of Rubus cuneifolius seed. Whereas scarification was found to break the dormancy imposed by the endocarp, embryo dormancy could only be overcome by a combination of treatments. These treatments consisted of a one-month stratification period followed by incubation at an alternating temperature ot 10–20 °C in the presence of light. S. Afr. J. Plant Soil 1984, 1: 48–50 Authorsvan Staden, J. and Campbell, Peta L. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634108 This article contributed by:
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| Response of five soybean (Glycine max (L.) Merr.) cultivars to lime and phosphorus on an acid Normandien subsoil | Noble, A. D. | 1984 |
KeywordsGlycine max (L.) Merr., liming, phosphorus, tolerance to aluminium AbstractFive soybean cultivars (Hill, Geduld, Forrest, Welkom and Oribi), previously selected for Al tolerance or sensitivity by a rapid seedling evaluation method, were grown in acid soil treated with varying rates of lime and P. After 35 days the plants were harvested and measurements of leaf area, shoot, root and nodule dry mass as well as elemental analysis were carried out. Lime had a significant effect on growth whilst P had relatively little effect. Classification for tolerance to soil acidity appeared to depend on the criterion used in the classification. Agreement with the ‘rag doll’-classification was obtained when comparing the cultivars, with respect to their relative shoot and leaf area yields, at the unlimed and first liming level. In the absence of lime the highest shoot yield occurred at the Intermediate level of P. Forrest appeared to perform consistently poorly in unlimed soils and could be classified as highly sensitive to acid soil infertility. However, it would be speculative lo classify the other cultivars into tolerant sensitive or intermediate groups. There was a strong indication that yield depressions in Forrest may not be attributed entirely to Al toxicity and that the relative balance of P, Fe and Cu may be involved Significant decreases in plant Al, Zn, Fe, Mn and Mg were observed with Increasing lime levels. S. Afr. J. Plant Soil 1984, 1: 51–56 AuthorsNoble, A. D., Lea, J. D. and Fey, M. V. Year Published1984 PublicationSouth African Journal of Plant and Soil LocationsDOI10.1080/02571862.1984.10634109 This article contributed by:
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