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Nendel C.,Leibniz Center for Agricultural Landscape Research
International Journal of Biometeorology | Year: 2010

Statistical analysis of bud break data for grapevine (Vitis vinifera L. cvs. Riesling and Müller-Thurgau) at 13 sites along the northern boundary of commercial grapevine production in Europe revealed that, for all investigated sites, the heat summation method for bud break prediction can be improved if the starting date for the accumulation of heat units is specifically determined. Using the coefficient of variance as a criterion, a global minimum for each site can be identified, marking the optimum starting date. Furthermore, it was shown that the application of a threshold temperature for the heat summation method does not lead to an improved prediction of bud break. Using site-specific parameters, bud break of grapevine can be predicted with an accuracy of ± 2.5 days. Using average parameters, the prediction accuracy is reduced to ± 4.5 days, highlighting the sensitivity of the heat summation method to the quality and the representativeness of the driving temperature data. © ISB 2009. Source

Zasada I.,Leibniz Center for Agricultural Landscape Research | Zasada I.,TU Munich
Land Use Policy | Year: 2011

Peri-urban areas around urban agglomerations in Europe and elsewhere have been subject to agricultural and land use research for the past three decades. The manner in which farming responds to urban pressures, socio-economic changes and development opportunities has been the main focus of examination, with urban demand for rural goods and services representing a driving factor to adapt farming activities in a multifunctional way. Working within the peri-urban framework, this review pays particular attention to the relevance of multifunctional agriculture. Academic discourses and empirical insights related to farm structure and practices beyond conventional agriculture are analysed. Diversification, recreational and environmental farming, landscape management and specialisation, as well as direct marketing are all taken into consideration and discussed within the context of landscape functions. The provision of rural goods and services is contrasted with societal demands on peri-urban agriculture. This review finds that multifunctional agriculture has been commonly recognised in peri-urban areas - a phenomenon that includes a large variety of activities and diversification approaches within the context of environmental, social and economic functions of agriculture. In response to the post-productive, consumption-oriented requirements of the urban society, peri-urban farmers have intensified their uptake of multifunctional activities. Nevertheless, not all multifunctional opportunities are being fully developed when one considers the large and growing urban demand for goods and services provided by agriculture carried out near the city. This paper discusses policy and planning approaches to support multifunctional agriculture in peri-urban areas. © 2011 Elsevier Ltd. Source

Miller B.A.,Leibniz Center for Agricultural Landscape Research
Cartography and Geographic Information Science | Year: 2014

Digital terrain analysis (DTA) provides efficient, repeatable, and quantified metrics of landscape characteristics that are important to the Earth sciences, particularly for detailed soil mapping applications. However, DTA has not been field tested to the extent that traditional field metrics of topography have been. Human assessment of topography synthesizes multiple parameters at multiple scales to characterize a landscape, based on field experience. In order to capture the analysis scale used by field scientists, this study introduces a method for calibrating the analysis scale of DTA to field assessments. This method is used to calibrate land-surface derivatives of relative elevation, profile curvature, and slope gradient in the context of the commonly used field description of hillslope position. For a topographically diverse landscape in MI, USA, a peak in agreement between field assessment and DTA was found at field equivalent distances of 135 m for relative elevation, 63 m for profile curvature, and 9 m for slope gradient. Given the field experience of soil scientists, these calibrations of DTA metrics are likely to have stronger correlations with hillslope properties and could be used together to classify hillslope position consistently across large extents. © 2014 Cartography and Geographic Information Society. Source

Kampen H.,Friedrich Loeffler Institute | Werner D.,Leibniz Center for Agricultural Landscape Research
Parasites and Vectors | Year: 2014

The Asian bush or rock pool mosquito Aedes japonicus japonicus is one of the most expansive culicid species of the world. Being native to East Asia, this species was detected out of its original distribution range for the first time in the early 1990s in New Zealand where it could not establish, though. In 1998, established populations were reported from the eastern US, most likely as a result of introductions several years earlier. After a massive spread the mosquito is now widely distributed in eastern North America including Canada and two US states on the western coast. In the year 2000, it was demonstrated for the first time in Europe, continental France, but could be eliminated. A population that had appeared in Belgium in 2002 was not controlled until 2012 as it did not propagate. In 2008, immature developmental stages were discovered in a large area in northern Switzerland and bordering parts of Germany. Subsequent studies in Germany showed a wide distribution and several populations of the mosquito in various federal states. Also in 2011, the species was found in southeastern Austria (Styria) and neighbouring Slovenia. In 2013, a population was detected in the Central Netherlands, specimens were collected in southern Alsace, France, and the complete northeastern part of Slovenia was found colonized, with specimens also present across borders in adjacent Croatia. Apparently, at the end of 2013 a total of six populations occurred in Europe although it is not clear whether all of them are completely isolated. Similarly, it is not known whether these populations go back to the same number of introductions. While entry ports and long-distance continental migration routes are also obscure, it is likely that the international used tyre trade is the most important mode of intercontinental transportation of the mosquito. Aedes j. japonicus does not only display an aggressive biting behaviour but is suspected to be a vector of various disease agents and to displace indigenous culicid species. Therefore, Aedes j. japonicus might both cause public health problems in the future and have a significant impact on the biodiversity of the invaded territories. © 2014 Kampen and Werner; licensee BioMed Central Ltd. Source

Gerke H.H.,Leibniz Center for Agricultural Landscape Research
Vadose Zone Journal | Year: 2012

This study attempts to quantify the interface between flow domains in macroscopic dual porosity flow and transport models. For a structured soil, this interface could be related to the surfaces of soil aggregates and bioprocess that may serve as preferential flow paths. Mass exchange with the soil matrix domain across this interface requires including the combined effect of various structural shapes and sizes, which has not yet been properly defined. The objective was to test an approach for independent soil structure quantification by characterizing domain interfaces based on surface area/volume ratios using two soil samples with contrasting structures. X-ray computed tomography data from undisturbed soil cores from a medical scanner were analyzed. For a range of density threshold values, surface areas were identified on a vowel basis. The resulting functions were found to be characteristic for the subsoil sample with cylindrical pinhole pores as well as for the aggregated topsoil sample. The results suggest that the interdomain interface area could be used for deriving mass exchange coefficients and a macroscopic characteristic related to visual inspection of the soil structure. The approach, representing an up scaling of individual structural features to the macroscopic scale, may improve the applicability of two-domain models by finding a way to obtain relatively simple estimates of the geometry coefficient from qualitative soil structure information given in soil protocols. Although this analysis did not allow determination of a well-defined interface between porous domains, it enabled narrowing of the range of possible values in a physically plausible region. Still more effort is required to identify specific types of structural surfaces among other features. © Soil Science Society of America. Source

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