ALBERT

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  • 1
    Electronic Resource
    Electronic Resource
    Nitrogen fertilization and sex expression affect size variability of fibre hemp (Cannabis sativa L.) (1995)
    Springer
    Oecologia 103 (1995), S. 462-470 
    Details
    ISSN: 1432-1939
    Keywords: Cannabis sativa L. ; Allometry ; Nitrogen fertilization ; Competition ; Sexual dimorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mechanical harvesting and industrial processing of fibre hemp (Cannabis sativa L.) require uniformity of stem length and weight. In 1991 and 1992 we carried out field experiments to investigate the effects of soil nitrogen level (80 and 200 kg ha-1N) and row width (12.5, 25 and 50 cm) on the variability of weight and height in hemp plants. The crops were sampled 5 times between early June and early September. Row width did not affect size variability. At final harvest coefficients of variation (CV) of both weight and height were about 1.5 times higher at 200 than at 80 kg ha-1N. Distributions of dry weight were positively skewed at all sampling dates except the first, with skewness larger at 200 than at 80 kg ha-1N. Distributions of height were negatively skewed at all sampling dates except the first at 80 kg ha-1N. At 200 kg ha-1N they changed from negative skewness during the first part of the growing season to negative kurtosis in the second part of the growing season. More suppressed plants were present at 200 than at 80 kg ha-1N. Contrary to most published results, we did not find a reduction of CV of weight nor of CV of height at the onset of self-thinning. Suppressed hemp plants can survive relatively well in the low-light environment under the canopy. Sexual dimorphism contributed to variability of height and weight, but the effects were smaller than those of nitrogen fertilization. The ratio of female to male plants was higher at 200 than at 80 kg ha-1N, as a result of a shift in sex-ratio within the population of suppressed plants. As suppressed plants were much more slender than dominating plants, self-thinning eliminated the most slender individuals in a hemp crop. However, the presence of many more heavy individuals of low slenderness at 200 than at 80 kg ha-1 N was probably the major cause of the difference in slenderness between 200 and 80 kg ha-1 N.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328684
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  • 2
    Electronic Resource
    Electronic Resource
    Tolerances of Old World bluestems to an acid soil high in exchangeable aluminum (1987)
    Springer
    Plant and soil 99 (1987), S. 39-46 
    Details
    ISSN: 1573-5036
    Keywords: Al toxicity ; Bothriochloa caucasica ; Bothriochloa intermedia ; Bothriochloa ischaemum ; Low imput agriculture ; Marginal soils ; Warm season grasses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Twenty-nine genotypes of Old World bluestems (Bothriochloa intermedia, B. ischaemum andB. caucasica) were screened for Al tolerance in greenhouse pots of acid Tatum subsoil which was unlimed at pH 4.1 and limed at pH 5.3. Three strains of weeping lovegrass (Eragrostis curvula) and El Reno side-oats grama grass (Bouteloua curtipendula) were also included as indicators of acid and alkaline soil tolerance, respectively. At pH 4.1 only 5 of the 29 bluestems and the 3 weeping lovegrasses produced measurable yields of tops or roots. The remaining 24 bluestems and side-oats grama either died or barely remained alive (due to frequent watering) with no appreciable growth. Weeping lovegrass was significantly more tolerant to the acid soil than any of the bluestems; relative top yields (pH 4.1/pH 5.3) were 101, 94 and 79% for the FQ71, common and FQ22 strains, respectively. Among the 5 bluestems that survived at pH 4.1, relative top yields ranged from 19 to 46%. Bluestems PI 300860 and PI 300857 (bothB. intermedia) appeared more tolerant than PI 300886 (B. intermedia) and PI 312442 (B. caucasica) with PI 300858 (B. intermedia) being intermediate; however, all 5 showed promise for use on acid soils that are high in exchangeable Al. Genotypes that failed to grow at pH 4.1 included members ofB. intermedia, B. ischaemum andB. caucasica. Some of these, such as PI 300825 (B. intermedia) and PI 300765 (B. caucasica), were among the highest yielders at pH 5.3. None of the 10 genotypes ofB. ischaemum survived at pH 4.1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02370152
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