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  • 1990-1994  (29)
  • 1950-1954  (5)
  • 1880-1889  (1)
  • 21
    Digitale Medien
    Digitale Medien
    Soil physical factors affecting the growth of sycamore (Acer pseudoplatanus L.) in a silvopastoral system on a stony upland soil in North-East Scotland (1993)
    Springer
    Agroforestry systems 24 (1993), S. 295-306 
    Details
    ISSN: 1572-9680
    Schlagwort(e): root growth ; soil compaction ; aeration ; soil strength ; soil moisture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tree growth and soil physical properties were compared on two grazed plots planted with sycamore at 5 and 10 m square spacing on an upland Scottish site. Both plots received fertilizer and stocking density of ewes and lambs was adjusted to maintain a constant sward height. Mean tree height in 1990 and height increment (1988–90) were significantly greater in the 5 m spaced plot (P〈0.05). Although matric potential under the trees was generally greater than in the grassed rows between trees, mean penetration resistance (37–107 mm depth) was significantly greater (P〈0.01) under the trees. Even when the soil was close to field capacity, less than 10% of penetrometer readings were 〈 1 MPa under the trees, in comparison to 44% in grassed areas between trees. This demonstrates that surface compaction due to preferential treading by sheep near the base of trees was sufficient to have seriously reduced tree root growth. Penetration resistance under the 5 m spaced trees was significantly less (P〈0.05) than under the 10 m spaced trees. A technique for estimating the probability of root deflections by stones (in 35 mm depth intervals), Ps, from penetrometer readings was used. A significant relationship (P〈0.1) was found between tree height increment and depth to Ps≥0.4 in the 10 m plot.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00705628
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  • 22
    Digitale Medien
    Digitale Medien
    Can Australian farming systems be more sylvan? (1993)
    Springer
    Agroforestry systems 22 (1993), S. 17-24 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Australian farming systems ; extension ; farmer attitudes ; revegetation ; policy vision
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper discusses the extent to which Australian agriculture is integrating trees into farming systems and concludes that while broad environmental awareness and concern may have increased, Australian agriculture exemplifies essentially the same attitudes to native vegetation as those held by the first European settlers. It is suggested that for real change to occur, land users require three key ingredients — commitment, knowledge and resources. The state of play with respect to each of these key factors is reviewed and suggestions for reform mooted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00707466
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  • 23
    Digitale Medien
    Digitale Medien
    Manual recording of minirhizotron data and its application to study the effect of herbicide and nitrogen fertiliser on tree and pasture root growth in a silvopastoral system (1994)
    Springer
    Agroforestry systems 26 (1994), S. 75-87 
    Details
    ISSN: 1572-9680
    Schlagwort(e): borescope ; competition ; herbicide ; minirhizotron ; pasture ; Prunus avium ; silvopastoral
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The use of a simple counting method using a borescope and minirhizotron system to study the interaction of roots of wild cherry trees (Prunus avium L) and pasture in an upland silvopastoral system is described. Operator variation was greatest when distinguishing different tree root categories (e.g. white, brown, woody) but was not significant in relation to total tree or grass root counts or species differences. Analysis of covariance was used to take these differences into account in a field trial using several operators. The seasonal patterns of tree and pasture root growth were different. Tree roots peaked in May before maximal shoot growth. The peak in pasture roots occurred two weeks earlier. Tree height growth was increased by the use of herbicides to control grass growth but this effect was only apparent during August when the soil was dry and when pasture root counts were reduced.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00707007
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  • 24
    Digitale Medien
    Digitale Medien
    Sex attractant pheromone of damson-hop aphid Phorodon humuli (Homoptera, aphididae) (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 3455-3465 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Pheromone ; sex ; attractant ; aphid ; Phorodon humuli ; Homoptera ; Aphididae ; nepetalactol ; monoterpenoid ; electrophysiology ; single cell recording ; mass spectrometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Behavioral studies using an olfactometer demonstrated that sexual females (oviparae) of the damson-hop aphid,Phorodon humuli, release a pheromone to which males respond. Volatiles produced by the oviparae were analyzed by coupled gas chromatography-single cell recording from the secondary rhinaria on the male antenna and showed the presence of one peak with major activity. Coupled gas chrornatography-mass spectrometry suggested a nepetalactol, which was shown to have the 4aR, 7S, 7aS stereochemistry by synthesis from the corresponding nepetalactone isolated from the labiate plantNepeta mussinii. Although the stereochemistry at carbon-1 is not yet established, a synthetic sample comprising ca. 70% 1S and 30% 1R attracted highly significant numbers of males to water traps placed within and adjacent to a hop garden. Initial studies also indicated attraction of males in both the olfactometer and in the field by volatiles from the primary host.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00982110
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  • 25
    Digitale Medien
    Digitale Medien
    Comparison of techniques for extracting volatile compounds from conifer needles (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2713-2722 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Monoterpenes ; Abies grandis ; Picea pungens ; steam distillation ; extraction ; secondary chemicals ; grand fir ; blue spruce ; coefficient of variation ; MANOVA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Five extraction techniques were used to obtain quantitative measurements of monoterpenes from blue spruce and grand fir needles. Multivariate analysis of variance indicated that there was a significant difference in the amount of each monoterpene extracted by using different techniques. For both species, an 8-hr steam distillation of 10 g of material yielded the greatest amount of each monoterpene. This technique was also the most reproducible in that the coefficients of variation were lowest. A rapid steam distillation was relatively effective for grand fir, but not for blue spruce. A CO2 extraction was unreliable for both species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00988080
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  • 26
    Digitale Medien
    Digitale Medien
    Spring migration of damson-hop aphid,Phorodon humuli (Homoptera, Aphididae), and summer host plant-derived semiochemicals released on feeding (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1569-1576 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Damson-hop aphid ; Phorodon humuli ; Homoptera ; Aphididae ; methyl salicylate ; (E)-2-hexenal ; β-caryophyllene ; semiochemicals ; aggregation ; attractant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Behavioral studies using an olfactometer demonstrated that spring migrants of the damson-hop aphid,Phorodon humuli, respond to semiochemicals released by spring migrants feeding on hop leaves. Samples of the total volatiles released on feeding were analyzed by coupled gas chromatographysingle cell recording techniques and showed the presence of several active components. Three compounds were identified, using coupled gas chromatography-mass spectrometry, as methyl salicylate, (E)-2-hexenal andβ-caryophyllene. These three compounds elicited responses from separate olfactory receptors on the antenna. In the olfactometer, both (E)-2-hexenal andβ-caryophyllene gave positive responses from spring migrants, and a mixture of the two compounds in the natural ratio was more attractive than (E)-2-hexenal alone. Addition of methyl salicylate eliminated the response to the active binary mixture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00984897
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  • 27
    Digitale Medien
    Digitale Medien
    Mr. Edwards on “ordinary language and absolute certainty” (1950)
    Springer
    Philosophical studies 1 (1950), S. 60-63 
    Details
    ISSN: 1573-0883
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Philosophie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02216992
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  • 28
    Digitale Medien
    Digitale Medien
    Distribution of soil invertase in relation to the root systems ofPicea sitchensis (Bong.) Carr. andAcer pseudoplatanus L. during development of young plants (1994)
    Springer
    Plant and soil 167 (1994), S. 73-77 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acer ; invertase ; Picea ; rhizosphere ; roots ; statistics ; trees
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A method is described for sampling rhizosphere soil under newly establishedPicea sitchensis andAcer pseudoplatanus. The technique involves taking soil samples to a depth of 150 mm at 100 mm intervals along transects, each 45° from its neighbour, radiating from the base of the stem. Invertase activities were measured in the soil samples and compared to their activities in fallow and rhizosphere soils. When the field soil was dry, the tree root systems were carefully excavated to retain as many fine roots as possible. The distribution of the soil invertase was matched to the spatial distribution of the roots showing the precise position of the rhizosphere relative to the initial ‘blind’ soil sampling. Statistics were applied to derive equations for calculating the percentage enzyme activity relative to that found in rhizosphere soil at various locations radiating from the base of the stem. This information was subsequently applied to soil sampled under trees of the same age as those excavated to give a non-destructive method for sampling rhizosphere soil routinely from under a large number of trees.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01587601
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  • 29
    Digitale Medien
    Digitale Medien
    A method for counting roots observed in minirhizotrons and their theoretical conversion to root length density (1993)
    Springer
    Plant and soil 153 (1993), S. 1-9 
    Details
    ISSN: 1573-5036
    Schlagwort(e): borescope ; minirhizotron ; pasture ; root length density ; silvopastoral ; wild cherry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A method for counting root intersections with observation tubes (mini- or micro-rhizotrons) is proposed that allows a theoretical conversion of root counts to estimated root length density and which is robust to the effects of tracking along the tubes. A field test showed that the method agreed well with measured root length densities in cores for wild cherry roots but not for roots of pasture species. The circumstances in which the method might be expected to perform well are discussed. Analysis of data from a field trial revealed that root counts were not uniformly distributed around the circumference of the observation tube. Implications for the design of such trials are noted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010539
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  • 30
    Digitale Medien
    Digitale Medien
    Current status and future strategy in breeding grasspea (Lathyrus sativus) (1993)
    Springer
    Euphytica 73 (1993), S. 167-175 
    Details
    ISSN: 1573-5060
    Schlagwort(e): ODAP ; BOAA ; neurotoxin ; Lathyrism ; drought-tolerance ; toxicology ; interspecific-hybridization ; mutation breeding ; germoplasm collections
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Efforts in grasspea (Lathyrus sativus) improvement have increased since the development of lines that are very low in the neurotoxin Beta-N-oxalyl-L-alpha-beta-diamino propionic acid (ODAP); also referred to as Beta-N oxalyl-amino-L-alanine (BOAA). Many programs now address several related aspects of improvement simultaneously. These include reduced ODAP concentrations, insect and disease resistance, nitrogen fixation, agronomic practices, fodder and forage production, and components for increased yielding ability. The coordinated, multidisciplinary approach now being applied to the genetic improvement of grasspea should allow the potential of this largely neglected grain legume to be fully realized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027192
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