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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 101 (1987), S. 211-221 
    ISSN: 1573-5036
    Schlagwort(e): aeration ; calcium ; cotton ; flooding ; magnesium ; manganese ; phosphorus ; potassium ; sodium chloride ; waterlogging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment was conducted to investigate the effects of intermittent waterlogging on the nutrient status of cotton (Gossypium hirsutum cv. Deltapine 61). The crop was grown in a sloping plot of soil in which a gradient of water-table depth ranging from 0.04m above to 0.60m below the soil surface was established during two periods of waterlogging in mid summer and early autumn. The first waterlogging lasted 8 days; the second lasted 16 days. Dry matter increases were less for severely waterlogged plants than for plants with well-aerated root systems during the first flooding, but the increases were similar during the second. Waterlogging impaired uptake of most nutrients by young plants in the first flooding, but had much less effect on nutrient uptake by older plants in the second. Waterlogging consistently reduced concentrations of P and K in the petioles and laminae of young fully-expanded leaves, and severely waterlogged plants were deficient in these nutrients by the end of the first flooding. Mn did not accumulate to toxic levels in waterlogged plants. During each flooding, waterlogged plants gained in total content of all nutrients studied, but the gains of each nutrient, except for Na, were proportionally smaller than for well-aerated plants. Fluxes of K-, Cl- and HPO4- ions in xylem sap exuded from stumps of detopped plants which had been waterlogged were lower than those from plants with well-aerated root systems. Seed cotton yields and concentrations of nutrients in mature bolls were not affected by the two periods of waterlogging. It is concluded that although intermittent waterlogging induced nutrient stress in cotton plants, especially for P and K in young plants before flowering, they recovered with no detrimental effect upon yield.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 126 (1985), S. 3-10 
    ISSN: 1573-5117
    Schlagwort(e): calcium ; bicarbonate ; sulphate ; acidity ; Rhine ; Rhone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Data on the chemical composition of the hard water rivers Rhine and Rhone, published elsewhere, are stored in a new data bank, RRQUE. In this paper the seasonal variation in pH and concentrations of calcium, bicarbonate and sulphate at 7 stations in the Rhine and 7 in the Rhone are described. The concentrations of calcium, bicarbonate and sulphate show important increases with increasing distance from the source. In both rivers acidification gradually occurs downstream and is thought to be caused by the decomposition of disposed organic matter. It is shown that the normal seasonal patterns of these 4 chemical variables are negated by anthropogenic effects.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1573-5117
    Schlagwort(e): pH ; calcium ; bicarbonate ; sulphate ; Rhine ; Rhone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the hard water rivers Rhine and Rhone the quotient Ca/HCO3 is strongly related to the sulphate concentration and not to the pH. The relationship can be described (by least square analysis) for the Rhine: Ca/HCO3) = 0.70 + 0.5 (SO4), for the Rhone: (Ca/HCO3) = 0.85 + 0.43 (SO4). With a Teissier analysis (reduced major axis) a slope for both rivers of 0.58 has been found. These values equal the theoretically expected value of 0.5, when a solution of CaSO4 is added to a saturated solution of CaCO3. The source of the CaSO4 (gypsum) is thought to be natural in the Rhone and anthropogenic in the Rhine. Acidification of both rivers is probably the result of decomposition of disposed organic matter.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1573-5117
    Schlagwort(e): calcium ; o-phosphate ; apatite ; solubility product ; Rhine ; Rhone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ionic product of 10750oxy-apatite has been calculated from data sets from the hard water rivers Rhine and Rhone. An overall value of 10−50 has been obtained, but this value has an uncertainty due to the uncertainty of the third ionisation constant of phosphoric acid. Implicitly it has been shown that these rivers are saturated with respect to 10750oxy-apatite and that thus calcium controls the solubility of o-phosphate.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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