Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Economie van de pacht
Silvis, Huib ; Voskuilen, Martien - \ 2018
Wageningen : Wageningen Economic Research (Wageningen Economic Research nota 2018-082) - 37
Deze notitie beschouwt het Nederlandse pachtstelsel in termen van marktwerking en overheidsingrijpen. Het huidige pachtstelsel is gemengd. Aan de ene kant is er de reguliere pacht die voorziet in een sterke bescherming van de pachter en in hoogst toelaatbare pachtprijzen. Aan de andere kant is er voor los land de geliberaliseerde pacht, waarvoor nauwelijks wettelijke bepalingen gelden en waarbij de pachtprijs vrij is. Sinds de jaren zestig is de koopmarkt van agrarische grond geheel vrij. Vooral vanwege de doorgaande bedrijfsvergroting is de betaalde grondprijs geen afspiegeling van de gemiddelde verdiencapaciteit van de grond. Dit levert een spanning op met de gereguleerde pachtprijs, die daar wel op gebaseerd is. Het pachtstelsel kan bijdragen aan drie functies: grondfinanciering voor landbouw, evenwichtige resultaatverdeling tussen pachter en verpachter, en doelmatig en flexibel grondgebruik. De huidige middelen van de pachtregelgeving zijn echter beperkt: pachtovereenkomsten worden vrijwillig aangegaan; op de afspraken tussen partijen is geen bestuurs- of strafrechtelijke controle door de overheid.
LiDAR derived topography and forest stand characteristics largely explain the spatial variability observed in MODIS land surface phenology
Misra, Gourav ; Buras, Allan ; Heurich, Marco ; Asam, Sarah ; Menzel, Annette - \ 2018
Remote Sensing of Environment 218 (2018). - ISSN 0034-4257 - p. 231 - 244.
Bavarian Forest National Park - Forest stand characteristics - Land cover - LiDAR - Modelling - Mountains - NDVI - Phenology - Spatial variability

In the past, studies have successfully identified climatic controls on the temporal variability of the land surface phenology (LSP). Yet we lack a deeper understanding of the spatial variability observed in LSP within a land cover type and the factors that control it. Here we make use of a high resolution LiDAR based dataset to study the effect of subpixel forest stand characteristics on the spatial variability of LSP metrics based on MODIS NDVI. Multiple linear regression techniques (MLR) were applied on forest stand information and topography derived from LiDAR as well as land cover information (i.e. CORINE and proprietary habitat maps for the year 2012) to predict average LSP metrics of the mountainous Bavarian Forest National Park, Germany. Six different LSP metrics, i.e. start of season (SOS), end of season (EOS), length of season (LOS), NDVI integrated over the growing season (NDVIsum), maximum NDVI value (NDVImax) and day of maximum NDVI (maxDOY) were modelled in this study. It was found that irrespective of the land cover, the mean SOS, LOS and NDVIsum were largely driven by elevation. However, inclusion of detailed forest stand information improved the models considerably. The EOS however was more complex to model, and the subpixel percentage of broadleaf forests and the slope of the terrain were found to be more strongly linked to EOS. The explained variance of the NDVImax improved from 0.45 to 0.71 when additionally considering land cover information, which further improved to 0.84 when including LiDAR based subpixelforest stand characteristics. Since completely homogenous pixels are rare in nature, our results suggest that incorporation of subpixel forest stand information along with land cover type leads to an improved performance of topography based LSP models. The novelty of this study lies in the use of topography, land cover and subpixel vegetation characteristics derived from LiDAR in a stepwise manner with increasing level of complexity, which demonstrates the importance of forest stand information on LSP at the pixel level.

Impacto de las variables ambientales en los niveles de PCDD/F y dl-PCB en la leche de la región agrícola de Chile
Pizarro-Aránguiz, Nicolás ; García-Mendoza, Diego ; Muñoz, Rubén ; San Martín, Betty ; Morales, Rodrigo - \ 2018
Ciencia e Investigacion Agraria 45 (2018)2. - ISSN 0304-5609 - p. 109 - 119.
Dioxin-like polychlorinated biphenyls - Environmental variables - Food contamination - Persistent organic pollutants - Polychlorinated dibenzo-p-dioxins - Polychlorinated dibenzofurans

According to a One Health perspective, the importance of persistent organic pollutants (POPs) must be assessed because of their impact on the environment, food chain and human health. However, information on these toxic compounds is limited in Latin America and the Caribbean region. Chile is no exception; therefore, this work aimed to explain previously reported dioxin levels in cow-milk samples by utilizing regression with meteorological/geographical data that were collected over a three-year survey. To accomplish this aim, a stepwise general multiple regression analysis was carried out for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs). The best statistical adjustments were achieved only for highly present congeners. Regarding PCDD/F congeners, the most relevant and significant (P <0.05) factors were the year (mostly a negative coefficient), the season, and the hectares affected by forest fires. In the case of dl-PCB congeners, there was a clear, positive relationship with the geographic parameter (UTM), and this result was consistent with previous findings that dl-PCB congeners show a trend with latitude. In contrast, wind speed was a significant negative coefficient for dl-PCBs. Despite existing knowledge on pollutant levels in milk, this study is relevant to better understand these findings in the Latin America and Caribbean regions.

Bioassays to Quantify Hygienic Behavior in Honey Bee (Apis Mellifera L.) Colonies : A Review
Leclercq, Gil ; Francis, Frédéric ; Gengler, Nicolas ; Blacquière, Tjeerd - \ 2018
Journal of Apicultural Research 57 (2018). - ISSN 0021-8839 - p. 663 - 673.
Apis mellifera - Ascosphaera apis - bioassays - hygienic behavior - Paenibacillus larvae - Varroa destructor

Individual immunity in honey bees (Apis mellifera L.) is complemented by highly evolved social behaviors. Among them, hygienic behavior has a key role involving the detection and removal of unhealthy or dead brood. Since the 1960s, several bioassays have been developed to quantify the hygienic behavior of honey bee colonies against chalkbrood, American foulbrood, and varroa infested brood. Here, we review the five main bioassays used since the late 1960s. We describe their advantages and disadvantages, including a special focus on their inherent biases. For each assay, we also discuss whether or not their use should be restricted to quantify the hygienic behavior against chalkbrood, or American foulbrood, or varroa infested brood. Overall, the bioassays involving the removal of freeze-killed brood are recommended over the bioassays relying on the removal of pin-killed brood but only for the quantification of hygienic behavior toward chalkbrood and American foulbrood. These bioassays are not recommended to quantify the hygienic behavior toward varroa infested brood, for which an accurate assessment should rely on assays based on the removal of brood artificially infested with varroa mites. Choosing an appropriate bioassay is crucial for an accurate assessment of the hygienic behavior against a defined pathogen, depending on the research question, or the goal of the breeding program. Bioensayos para cuantificar el comportamiento higiénico en las colonias de abejas melíferas (Apis mellifera L.): una revisión La inmunidad individual de las abejas melíferas (Apis mellifera L.) se complementa con comportamientos sociales altamente evolucionados. Entre ellos, el comportamiento higiénico tiene un papel clave en la detección y eliminación de crías enfermas o muertas. Desde la década de 1960, se han desarrollado varios bioensayos para cuantificar el comportamiento higiénico de las colonias de abejas melíferas frente a la cría infestada de Ascosfera, loque americana y varroa. Aquí revisamos los cinco principales bioensayos utilizados desde finales de la década de 1960. Describimos sus ventajas y desventajas, incluyendo un enfoque especial en sus sesgos inherentes. Para cada ensayo, también discutimos si su uso debe ser restringido o no para cuantificar el comportamiento higiénico contra la cría de loque americana o la cría infestada de varroa. En general, los bioensayos que involucran la eliminación de la cría muerta por congelación son más recomendables que los bioensayos que dependen de la eliminación de la cría muerta por pin, pero sólo para la cuantificación del comportamiento higiénico hacia la cría infestada de Ascosfera y la loque americana. Estos bioensayos no se recomiendan para cuantificar el comportamiento higiénico de la cría infestada de varroa, para lo cual una evaluación precisa debe basarse en ensayos basados en la extracción de la cría infestada artificialmente con ácaros de la varroa. La elección de un bioensayo apropiado es crucial para una evaluación precisa del comportamiento higiénico frente a un patógeno definido, dependiendo de la pregunta de investigación o del objetivo del programa de cría.

A global climate niche for giant trees
Scheffer, Marten ; Xu, Chi ; Hantson, Stijn ; Holmgren, Milena ; Los, Sietse O. ; Nes, Egbert H. van - \ 2018
Global Change Biology 24 (2018)7. - ISSN 1354-1013 - p. 2875 - 2883.
alternative ecosystem state - canopy height - LiDAR - precipitation temperate rainforest - remote sensing - resilience - threshold - tropical rainforest

Rainforests are among the most charismatic as well as the most endangered ecosystems of the world. However, although the effects of climate change on tropical forests resilience is a focus of intense research, the conditions for their equally impressive temperate counterparts remain poorly understood, and it remains unclear whether tropical and temperate rainforests have fundamental similarities or not. Here we use new global data from high precision laser altimetry equipment on satellites to reveal for the first time that across climate zones ‘giant forests’ are a distinct and universal phenomenon, reflected in a separate mode of canopy height (~40 m) worldwide. Occurrence of these giant forests (cutoff height > 25 m) is negatively correlated with variability in rainfall and temperature. We also demonstrate that their distribution is sharply limited to situations with a mean annual precipitation above a threshold of 1,500 mm that is surprisingly universal across tropical and temperate climates. The total area with such precipitation levels is projected to increase by ~4 million km2 globally. Our results thus imply that strategic management could in principle facilitate the expansion of giant forests, securing critically endangered biodiversity as well as carbon storage in selected regions.

Pachtnormen 2018 : Berekening hoogst toelaatbare pachtprijzen voor los land, agrarische bedrijfsgebouwen en agrarische woningen
Silvis, H.J. ; Meer, R.W. van der; Voskuilen, M.J. - \ 2018
Wageningen : Wageningen Economic Research (Wageningen Economic Research rapport 2018-055) - ISBN 9789463432849 - 25
In opdracht van het ministerie van Landbouw, Natuur en Voedselkwaliteit heeft Wageningen Economic Research de hoogst toelaatbare pachtprijzen voor 2018 berekend conform de uitgangspunten van het Pachtprijzenbesluit 2007. Voor los bouw- en grasland is de gemiddelde grondbeloning in de periode 2012-2016 lager uitgevallen dan in de periode 2011-2015, vooral door de zeer matige resultaten van de melkveehouderij in 2016. Hierdoor dalen de pachtnormen 2018 ten opzichte van de pachtnormen 2017 in dertien van de veertien gebieden. De veranderpercentages voor pachtcontracten afgesloten voor 1 september 2007 lopen uiteen van -34 voor het Zuidelijk veehouderijgebied tot +7 voor de IJsselmeerpolders.
Megaproyectos hidráulicos y aguas urbanizadas"las relaciones urbano-rurales y los territorios hidrosociales en las cuencas de Lima
Hommes, L.M. - \ 2018
In: A contracorriente / Vila Benites, Gisselle, Bonelli, Cristobal, Quito : Justicia Hídrica (Agua y Sociedad 25) - ISBN 9789942094742 - p. 359 - 399.
Mineria y conflictos sobre agua y tierra: el caso de la mineria de oro en Cerro de San Pedro, México
Stoltenborg, D. ; Boelens, R.A. - \ 2018
In: Los Caminos del Agua / Arroyo Castillo, Aline, Isch Lopez, Edgar, Quito : Justicia Hídrica (Agua y Sociedad 26) - ISBN 9789942094230 - p. 23 - 49.
Sistema multipropósito de agua Jaime Roldós Agyukera: el territorio hidrosocial como escenario de disputa y resistencia
Hidalgo, Jean Pablo ; Boelens, R.A. ; Isch Lôpez, E. - \ 2018
In: Los Caminos del Agua / Arroyo Castillo, Aline, Isch Lopez, Edgar, Quito : Justicia Hídrica (Agua y Sociedad 26) - ISBN 9789942094230 - p. 109 - 132.
Construcción de represas en el sudeste de Turquía: Iuchas y reclamos alrededor de la represa de Ilisu
Hommes, L.M. - \ 2018
In: Los Caminos del Agua / Arroyo Castillo, Aline, Isch Lopez, Edgar, Quito : Justicia Hídrica (Agua y Sociedad 26) - ISBN 9789942094230 - p. 133 - 152.
El páramo de Sunturbán, Colombia: disputas de la conceptualización y valoraciÍon de un territorio hidrosicial
Duarte, B. ; Boelens, R.A. - \ 2018
In: Los Caminos del Agua / Arroyo Castillo, Aline, Isch Lopez, Edgar, Quito : Justicia Hídrica (Agua y Sociedad 26) - ISBN 9789942094230 - p. 153 - 179.
Floristic diversity and cultural importance in agroforestry systems on small-scale farmer's livelihoods in central Veracruz, México
Pietersen, Sjoerd ; López-Acosta, Juan Carlos ; Gomez-Díaz, Jorge Antonio ; Lascurain-Rangel, Maite - \ 2018
Sustainability 10 (2018)1. - ISSN 2071-1050
Ethnobotany - Importance value index - Native woody plant species - Plant conservation - Tropic
México is a cultural and biological megadiverse country with an increased anthropogenic pressure on its tropical landscapes. The study area was the ejido "Los ídolos", Misantla, Central Veracruz, Mexico. The main objective of this research was to identify how the woody plant diversity of agroforestry systems contributed to the cultural, economic, and subsistence security of local farmers. Five different agroforestry systems were identified: forest gardens (FG), home gardens (HG), plantation crop combination with perennial cultivates (PC), plantation crop combinations with annual cultivates (AC), and trees on pastures (TP). FG systems had the highest floristic diversity, followed by HG and TP. Interviews with farmers showed that FG, HG, and PC systems were important for maintaining cultural identity and secure subsistence needs, while PC and TP systems were important for improving the economic situation of farmers. The FG systems contained only native species, while the proportion of exotic plants differed among the other systems. Useful exotic plants were found in the HG system. This study demonstrated that agroforestry systems such as FG were not used to their full potential, despite their high diversity of useful plants. It is recommended that farmers-assisted by institutions and representatives of local product chains-conduct feasibility studies on the marketing and promotion of products derived from specific agroforestry systems.
Genetische vooruitgang sneller dan opbrengststijging - Maximale opbrengst vaak niet rendabel
Rijk, Bert ; Ittersum, Martin van - \ 2018

Nieuwe rassen van de belangrijkste akker­bouwgewassen bieden nog steeds een verdere potentiele opbrengststijging. Het gat tussen de behaalde opbrengsten en de potentiele opbrengsten wordt echter steeds groter. Dat blijkt uit een analyse uitgevoerd door WUR PAGV.

Nieuwe rassen van de belangrijkste akker­bouwgewassen bieden nog steeds een verdere potentiele opbrengststijging. Het gat tussen de behaalde opbrengsten en de potentiele opbrengsten wordt echter steeds groter. Dat blijkt uit een analyse uitgevoerd door WUR PAGV.


In de internationale literatuur duiken steeds vaker artikelen op waaruit blijkt dat praktijkopbrengsten in hoogproductieve landen stagneren. Reden genoeg voor WUR-onderzoekers om een eerder onderzoek aan rassenproeven in Nederland over de jaren tot 2010 te herhalen met de nieuwste gegevens. Met een specifieke statistische analyse van rassenproeven kan de invloed van veranderend klimaat, maar ook de CO2-concentratie in de lucht (E) en gewijzigde teeltmaatregelen (M) gescheiden wordenvan het effect vande introductie van nieuwe rassen (G).De opbrengst van een gewas hangt af van de genetische eigenschappen van het ras, het klimaat en de teeltmaatregelen (dit wordt afgekort als GxExM = genetics x environment x management).

Uit analyse van rassenproeven die zijn uitgevoerd van 1980 tot 2016 in wintertarwe, zomergerst, zetmeelaardappelen en suikerbieten blijkt dat het opbrengend vermogen van nieuwe rassen van deze gewassen blijft stijgen, los van weers-en klimaatinvloeden en verbeterd gewasmanagement.

Minería y conflictos sobre agua y tierra: el caso de la minería de oro en Cerro de San Pedro, México
Stoltenborg, D. ; Boelens, R.A. - \ 2017
In: Los Caminos del Agua / Castillo, Arroyo, Isch Lopez, E., Quito : Abya Yala - ISBN 9789942094230 - p. 25 - 50.
Sistema multipropósito de agua Jaime Roldós Aguilera: el territorio hidrosocial como escenario de disputa y resistencia
Hidalgo, Juan Pablo ; Boelens, R.A. ; Isch Lôpez, E. - \ 2017
In: Los Caminos del Agua / Artoyo, Aline, Isch Lopez, Edgar, Quito : Abya Yala - ISBN 9789942094230 - p. 109 - 132.
El páramo de Santurbán, Colombia: disputas de la conceptualización y valoración de un territorio hidrosocial
Duarte-Abadía, Bibiana ; Boelens, R.A. - \ 2017
In: Los Caminos del Agua / Arroyo, Aline, Isch Lopez, Edgar, Quito : Abya Yala - ISBN 9789942094230 - p. 153 - 178.
The Sexy Crop
Kema, Gert - \ 2017
Seminar at the AGRI-FOOD LECTURE, SEARCA Auditorium, UP-Los Baños, Philip-pines. “Innovation for sustainability: What can the Philippine-Netherlands partnership contribute?” A joint effort by the Embassy of the Kingdom of the Netherlands and the University of the Philippines – Los Baños College of Agriculture, College of Economics and Management and Center for Technology Transfer and Entrepreneurship
Field evidence for transfer of plastic debris along a terrestrial food chain
Huerta Lwanga, Esperanza ; Mendoza Vega, Jorge ; Ku Quej, Victor ; Angeles Chi, Jesus de los; Sanchez del Cid, Lucero ; Chi, Cesar ; Escalona Segura, Griselda ; Gertsen, Henny ; Salánki, Tamás ; Ploeg, Martine van der; Koelmans, Bart ; Geissen, Violette - \ 2017
Scientific Reports 7 (2017). - ISSN 2045-2322 - 7 p.
Although plastic pollution happens globally, the micro- (<5 mm) and macroplastic (5–150 mm) transfer of plastic to terrestrial species relevant to human consumption has not been examined. We provide first-time evidence for micro- and macroplastic transfer from soil to chickens in traditional Mayan home gardens in Southeast Mexico where waste mismanagement is common. We assessed micro- and macroplastic in soil, earthworm casts, chicken feces, crops and gizzards (used for human consumption). Microplastic concentrations increased from soil (0.87 ± 1.9 particles g−1), to earthworm casts (14.8 ± 28.8 particles g−1), to chicken feces (129.8 ± 82.3 particles g−1). Chicken gizzards contained 10.2 ± 13.8 microplastic particles, while no microplastic was found in crops. An average of 45.82 ± 42.6 macroplastic particles were found per gizzard and 11 ± 15.3 macroplastic particles per crop, with 1–10 mm particles being significantly more abundant per gizzard (31.8 ± 27.27 particles) compared to the crop (1 ± 2.2 particles). The data show that micro- and macroplastic are capable of entering terrestrial food webs.
The Usumacinta-Grijalva beach-ridge plain in southern Mexico : A high-resolution archive of river discharge and precipitation
Nooren, Kees ; Hoek, Wim van der; Winkels, Tim ; Huizinga, Annika ; Plicht, Hans Van Der; Dam, Remke L. Van; Heteren, Sytze Van; Bergen, Manfred J. Van; Prins, Maarten A. ; Reimann, Tony ; Wallinga, Jakob ; Cohen, Kim M. ; Minderhoud, Philip ; Middelkoop, Hans - \ 2017
Earth Surface Dynamics 5 (2017)3. - ISSN 2196-6311 - p. 529 - 556.
The beach-ridge sequence of the Usumacinta-Grijalva delta borders a 300 km long section of the southern Gulf of Mexico coast. With around 500 beach ridges formed in the last 6500 years, the sequence is unsurpassed in the world in terms of numbers of individual ridges preserved, continuity of the record, and temporal resolution. We mapped and dated the most extensively accreted part of the sequence, linking six phases of accretion to river mouth reconfigurations and constraining their ages with 14C and OSL dating. The geomorphological and sedimentological reconstruction relied on lidar data, coring transects, GPR measurements, grain-size analyses, and chemical fingerprinting of volcanic glass and pumice encountered within the beach and dune deposits. We demonstrate that the beach-ridge complex was formed under ample long-term fluvial sediment supply and shorter-term wave-A nd aeolian-modulated sediment reworking. The abundance of fluvially supplied sand is explained by the presence of easily weatherable Los Chocoyos ignimbrites from the ca. 84 ka eruption of the Atitlán volcano (Guatemala) in the catchment of the Usumacinta River. Autocyclic processes seem responsible for the formation of ridge-swale couplets. Fluctuations in their periodicity (ranging from 6-19 years) are governed by progradation rate, and are therefore not indicative of sea level fluctuations or variability in storm activity. The fine sandy beach ridges are mainly swash built. Ridge elevation, however, is strongly influenced by aeolian accretion during the time the ridge is located next to the beach. Beach-ridge elevation is negatively correlated with progradation rate, which we relate to the variability in sediment supply to the coastal zone, reflecting decadal-scale precipitation changes within the river catchment. In the southern Mexican delta plain, the coastal beach ridges therefore appear to be excellent recorders of hinterland precipitation.
Frugalidad e innovación popular: nuevos caminos para la sustentabilidad y la inclusión social en Ecuador.
Pansera, Mario ; Rivas Hermann, Roberto ; Narvaez Mena, H. - \ 2017
Revista Iberoamericana de Ciencia Tecnologia Y Sociedad 12 (2017)35. - ISSN 1668-0030 - p. 131 - 152.
Este artículo explora los conceptos de innovación popular e innovación frugal y su potencial para la generación de un conocimiento capaz de producir un desarrollo más sostenible e inclusivo. La innovación frugal o popular, a menudo llevada a cabo en condiciones de escasez de recursos materiales y financieros, intenta solucionar de manera simple, pero muy efectiva, los problemas concretos de la gente común. En su primera parte, este artículo introduce los conceptos de innovación popular desde la perspectiva teórica y sucesivamente describe los resultados de un trabajo etnográfico llevado a cabo en Ecuador. En particular, el trabajo empírico busca describir, a través de cuatro estudios de caso, el potencial existente en Ecuador. El artículo concluye con la propuesta de una agenda de investigación y una serie de medidas para fomentar y facilitar la valorización de este potencial y su integración en un marco más amplio de políticas públicas.
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