Papers by Paul Van Der Voet
GlobVolcano: Earth Observation Services for Global Monitroing of Active Volcanoes
ESASP, Mar 1, 2010
Zenodo (CERN European Organization for Nuclear Research), Dec 15, 1999
Satellite-and ground-based measurement of WDVI to reduce herbicide use in potato haulm killing
ABSTRACT When using variable-rate technology (VRT), tractor-mounted sensors are typically used to... more ABSTRACT When using variable-rate technology (VRT), tractor-mounted sensors are typically used to measure crop status. Crop status can also be measured with a satellite. The first objective of our work was to establish a relationship between the Weighted Difference Vegetation Index (WDVI) in potato as measured with a Cropscan reflectance meter on the one hand and WDVI as measured with the Aster and Worldview satellites on the other hand. The scale at which VRT is applied is an important determinant of the reduction in input use. The second objective was to estimate the potential to reduce herbicide use for potato haulm killing as a function of the size of decision units, using the above-determined relationship between Cropscan-WDVI and satellite-WDVI, satellite imagery of 13 producers’ fields and a previously developed decision rule for herbicide application. We found that ground-based WDVI and satellite-based WDVI are strongly and linearly related, thus making it feasible to calculate herbicide application rate for potato haulm killing on the basis of satellite-based measurements. We found that when the size of the decision unit was 15 x 15 m2 (the size of an Aster pixel), a reduction in herbicide use of at least 50% would be achieved in one out of every two of the fields, and a reduction of at least 33% would be achieved in all fields. When the size of the decision unit was 30 x 30 m2, a reduction of at least 33% would be achieved in one out of every two of the fields. In conclusion, satellite-measurements can be used in place of ground-based crop reflectance measurements for determining herbicide application rate for potato haulm killing. Our work confirms previous estimates that a 50% reduction in herbicide use for potato haulm killing can be achieved with VRT.
… 2010, held 2-7 May …, 2010
The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate ...
ESA Living Planet Symposium, Dec 1, 2010
Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del p... more Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del programma Data User Element (DUE). Il progetto è finalizzato alla realizzazione e dimostrazione di un servizio a scala globale, basato su dati di osservazione della terra (EO Earth Observation), a supporto delle attività degli Osservatori Vulcanologici e/o Enti di Protezione Civile incaricati della sorveglianza in aree vulcaniche attive. Nel corso della prima fase del progetto il sistema informativo è stato progettato, sviluppato e validato. La validazione è stata effettuata per un numero limitato di aree test (Colima in Messico,
GlobVolcano pre-operational services for global monitoring active volcanoes
The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate users (e.g. Civil Protection) in their monitoring activities. The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. In a first phase, a complete information system has been designed, implemented and validated, involving a limited number of test areas and respective user organizations. In the currently on-going second phase, GlobVolcano is delivering pre-operational services over 15 volcanic sites located in three continents and as many user organizations are involved and cooperating with the project team. The set of GlobVolcano offered EO based information products is composed as follows: Deformation Mapping DInS...
Journal of Environmental Management, 2009
The overall objective of the Ramsar Convention, signed in 1971, is the conservation and wise use ... more The overall objective of the Ramsar Convention, signed in 1971, is the conservation and wise use of wetlands by national action and international cooperation as a means to achieving sustainable development. This complex and challenging task requires national, local and international bodies involved in the implementation of the convention to rely on suitable geo-information to better understand wetland areas, complete national inventories, perform monitoring activities, carry out assessments and put in practice suitable management plans based on updated and reliable information. In the last years, Earth Observation (EO) technology has been revealed as a key tool and unique information source to support the environmental community in different application domains, including wetlands' conservation and management. In this context, the European Space Agency (ESA) in collaboration with the Ramsar Secretariat launched in 2003 the ''GlobWetland'' project in order to demonstrate the current capabilities of Earth Observation technology to support inventorying, monitoring, and assessment of wetland ecosystems. This paper collects the main results and findings of the ''GlobWetland'' project, providing an overview of the current capabilities and limits of EO technology as a tool to support the implementation of the Ramsar Convention. The project was carried out in collaboration with several regional, national and local conservation authorities and wetland managers, involving 50 different wetlands across 21 countries on four continents. This large range of users provided an excellent test bed to assess the potential of this technology to be applied in different technical, economic and social conditions.
European Journal of Agronomy, 2012
A low basal N application combined with in-season adjustment of the sidedress N rate has been pro... more A low basal N application combined with in-season adjustment of the sidedress N rate has been proposed as a means to save N in growing potato (Solanum tuberosum L.). We hypothesize that a measurement of canopy reflectance provides information which can be used to adjust sidedress N rate. The objective of our work was to develop and test a canopy reflectance-based N sidedress system for potato in humid climates. In four years of experiments with ware potato on a sandy soil it was determined that the reflectance index WDVI correlates well with N uptake, that sidedress N should be applied at around the time of canopy closing, and that the sidedress N rate should be calculated as the difference between a (fixed) desired N uptake and a reflectance-based measurement of N uptake. The calculated N saving in these experiments was between 10 and 109 (average 56) kg N ha −1 . The reflectance-based N sidedress system was tested at an additional two locations, with ware potatoes on a loamy soil and with starch potatoes on a sandy soil, in two further years of experiments. N saving in these experiments was between 8 and 88 (average 44) kg N ha −1 . In both sets of experiments, yields with the sidedress system were generally at the same level as yields obtained with recommended N rates (basal N only). We conclude that the reflectance-based sidedress N system allows saving of N while maintaining yield.
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Papers by Paul Van Der Voet