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Fady B. Ducci F. Aleta N. Becquey J. Diaz Vazquez R. Fernandez Lopez F. Jay-Allemand C. Lefèvre F. Ninot A. Panetsos K. Paris P. Pisanelli A. Rumpf H. 《New Forests》2003,25(3):211-225
Adaptive and wood quality trait data were collected and analyzed on commercially available Juglans regia and J. regia×J. nigra provenances and progenies planted across Europe in a multi-site network. A total of 19 seed sources, replicated 35 times per site, were planted at 13 sites from 5 European countries, encompassing the potential distribution area of timber production plantation sites. The following traits were evaluated: survival, height, diameter at breast height, stem form, apical dominance, vegetative budbreak, along with biotic and abiotic damage. Mean values were significantly different both among provenances/progenies and sites. Most common damage was late spring and early autumn frost. Bud break ranking was significantly correlated with provenance and progeny origin. Although J. regia is fast growing, southern European early budbreak plant material should not be planted under most middle European conditions where late spring frost can be expected, as it has a significant negative impact on architectural (and thus wood quality) traits. Hybrid J. regia×J. nigra progeny performed better than J. regia provenances/progenies for most traits measured. Differences were significantly in favor of hybrids at sites with medium to low fertility, although some locally selected seed sources tended to perform as well as hybrids on high fertility sites. 相似文献
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1. The development of prenatal acoustic communication was investigated in Muscovy ducks, comparing the vocalisation activities and call types in isolated eggs and pairs of embryos (two eggs in shell contact).
2. Incubator experiments showed that the number of vocalisations in embryos which had mutual acoustic contact was nearly twice that of isolated ones.
3. An acoustic interaction, that is, an exchange of signals, was only recognised after the first chick had hatched, that is, between embryos and chicks.
4. Specific call types used for communication were the double call and the trill call. 相似文献
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Addition of wood ash to acid soils will affect the soil chemistry of forests in a number of ways which were assessed for a pine stand in northern Germany. A field experiment was carried out in a fifty‐year old pine stand on a sandy Podzol at Fuhrberg (Lüneburger Heide, Lower Saxony/Germany) which involved depositing wood ash (2.4 t ha—1) on the surface. Soil solution chemistry was investigated monthly at different depths for 24 months. Prior to and 19 months after the ash addition, exchangeable cations and amounts of heavy metals were determined at different depths. Two to four months after addition of wood ash, maximum mean concentrations in the soil solution of Ca were 240 μmol l—1 at 0 cm (surface of mineral soil) and 100 μmol l—1 at 100 cm and of K 980 μmol l—1 and 140 μmol l—1, respectively. The pH values in soil solutions dropped temporarily by 0.3 units at 0 and 10 cm depth. Nitrate concentrations increased at all depths and maximum mean concentration was 230 μmol l—1 at 100 cm. Concentrations of Pb and Cr in soil solution did not change significantly (p < 0.05) after ash addition. Concentrations of Cd and Zn increased significantly at some depths but stayed well below the legal limit for drinking water and below the limits given by the German recommendation for soil conservation. Nineteen months after ash addition, the cation exchange capacity (corrected for the release of cations from the ash) of the upper 6 cm of the organic layer was almost doubled and amounts of exchangeable Ca and Mg increased significantly in the upper 8 cm of the organic layer. Amounts of Zn were increased in the entire organic layer, but changes were significant only in the upper 4 cm. The results of this study suggest that ash from untreated wood (using modest additions) may be recommended for amelioration of forest soils. 相似文献
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Günther Rumpf 《Potato Research》1973,16(4):296-301
Summary In two series of experiments, batches of potatoes, some treated by irradiation and some with chemical sprout inhibitors, were
processed into chips on an industrial scale after 7–8 months of storage. The quality of the chips and of the stored fresh
potatoes was related to gas chromatographic analyses of sugar and acid contents.
It was found that only the irradiated potatoes in which the content of fructose and glucose at the time of processing amounted
to not more than 0.07% each of the fresh weight, yielded marketable chips of good quality. If the concentrations of reducing
sugars were as low as this, then the rate of rotting was also very low, even in the irradiated batches. Shipment of the potatoes
by truck over a distance of approximately 300 km after irradiation had no detectable deleterious effect. 相似文献
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Early detection and classification of plant diseases with Support Vector Machines based on hyperspectral reflectance 总被引：5，自引：0，他引：5
T. Rumpf A.-K. Mahlein U. Steiner H.-W. Dehne 《Computers and Electronics in Agriculture》2010,74(1):91-162
Automatic methods for an early detection of plant diseases are vital for precision crop protection. The main contribution of this paper is a procedure for the early detection and differentiation of sugar beet diseases based on Support Vector Machines and spectral vegetation indices. The aim was (I) to discriminate diseased from non-diseased sugar beet leaves, (II) to differentiate between the diseases Cercospora leaf spot, leaf rust and powdery mildew, and (III) to identify diseases even before specific symptoms became visible. Hyperspectral data were recorded from healthy leaves and leaves inoculated with the pathogens Cercospora beticola, Uromyces betae or Erysiphe betae causing Cercospora leaf spot, sugar beet rust and powdery mildew, respectively for a period of 21 days after inoculation. Nine spectral vegetation indices, related to physiological parameters were used as features for an automatic classification. Early differentiation between healthy and inoculated plants as well as among specific diseases can be achieved by a Support Vector Machine with a radial basis function as kernel.The discrimination between healthy sugar beet leaves and diseased leaves resulted in classification accuracies up to 97%. The multiple classification between healthy leaves and leaves with symptoms of the three diseases still achieved an accuracy higher than 86%. Furthermore the potential of presymptomatic detection of the plant diseases was demonstrated. Depending on the type and stage of disease the classification accuracy was between 65% and 90%. 相似文献
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