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Widespread mortality of Cordilleran cypress (Austrocedrus chilensis) occurs in developed and pristine forests in south-western Argentina and possibly south-eastern Chile. Affected trees may die rapidly but mortality is commonly preceded by several decades of severely restricted radial stem growth. Roots are often affected by one or more types of decay. Cypress mortality, locally termed ‘mal del cipres’, is similar to a major forest disease in North America: Port-Orford-cedar (Chamaecyparis lawsoniana) root disease in Oregon and California and a major tree decline: Alaska yellow-cedar (Chamaecyparis nootkatensis) decline in south-east Alaska. This paper discusses several hypotheses concerning mal del cipres and compares current forest decline research in Patagonia with North America. 相似文献
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Three methods of automatic classification of leaf diseases are described based on high-resolution multispectral stereo images.
Leaf diseases are economically important as they can cause a loss of yield. Early and reliable detection of leaf diseases
has important practical relevance, especially in the context of precision agriculture for localized treatment with fungicides.
We took stereo images of single sugar beet leaves with two cameras (RGB and multispectral) in a laboratory under well controlled
illumination conditions. The leaves were either healthy or infected with the leaf spot pathogen Cercospora beticola or the rust fungus Uromyces betae. To fuse information from the two sensors, we generated 3-D models of the leaves. We discuss the potential of two pixelwise
methods of classification: k-nearest neighbour and an adaptive Bayes classification with minimum risk assuming a Gaussian mixture model. The medians of
pixelwise classification rates achieved in our experiments are 91% for Cercospora beticola and 86% for Uromyces betae. In addition, we investigated the potential of contextual classification with the so called conditional random field method,
which seemed to eliminate the typical errors of pixelwise classification. 相似文献
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Investigations were conducted to evaluate the effects of long-term (up to 100 years) wastewater irrigation on the selected microbiological and biochemical characteristics of a Cambisol and a Haplic Luvisol. The developments of soil oligotrophic and copiotrophic bacteria (including actinomycetes), the total microbial biomass (ATP content), and acitivity of enzymes catalyzing major substrate transformations in soil (β-glucosidase, β-acetyl-glucosaminidase, proteinase, phosphatase) indicated significantly differences between wastewater treated and non-irrigated soil sites. The increases of the individual indices under the effect of wastewater irrigation show that remarkable differences in the microbiological and biochemical parameters of soil quality remained detectable also 20 years after the soil treatment was terminated. 相似文献
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Obhodas Jasmina Tinivella Umberta Giustiniani Michela Durn Tatjana Vinkovic Andrija Radic Sara Soprun Filip Sudac Davorin 《Journal of Soils and Sediments》2020,20(6):2724-2732
Journal of Soils and Sediments - There is a growing understanding that methane hydrates (MHs) distributed globally in permafrost and deep sea sediments present an enormous unconventional reservoir... 相似文献