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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    The interplay between osmoregulation and digestive functioning in the gastrointestinal tract in salmonids: impacts of dietary factors
    Ciavoni, Elisa - \ 2020
    In: Wias Annual Conference 2020 WIAS - p. 61 - 61.
    Modern feeds, used in aquaculture, have an extremely high dry matter (DM) content which may be challenging for proper functioning of the gastrointestinal tract (GIT) in farmedfish (Buddington et al., 1997). The majority of physiological studies has been carried on using fasted fish. Therefore, the dietary impact on GIT osmo regulation and the interaction between osmoregulation and digestion is largely unknown. Nowadays, it is recognized that feeding entails a physiological strain inside the GIT by altering ion balances (Wood and Bucking, 2010). Moreover, different challenges are faced by fish depending on the diet composition and environment (i.e., freshwater or saltwater). It is hypothesised that the diet composition has an impact on several osmoregulatory processes including mineral uptake and excretion, which also depend on the salinity of the aquatic medium.Therefore, the overall objective of the present project is to understand the interaction between osmoregulation and digestive functioning of GIT in salmonids during freshwater(FW) and saltwater (SW) life stages. Fish will be fed diets with contrasting levels of moisture content, dietary electrolyte balances (dEB), calcium (Ca2+) load and buffering capacity.The experimental design has been planned in order to test the above-mentioned dietary factors through in vivo experiments (Phase 1) using freshwater rainbow trout (Oncorhynchusmykiss) as experimental animal. Phase 1 aims at identifying which of the a forementioned factors interact with osmoregulation and digestion within the GIT of freshwater rainbow trout by altering chyme conditions through the diet. The observed alteration in chyme conditions in vivo in Phase 1, will be studied in vitro (Phase 2) at three levels of digestive functioning namely (a) digestive enzyme activity, (b) epithelial nutrient uptake and (c)gut motility/peristalsis. Finally, the consequences of moving from freshwater into seawater on digestive functioning (macronutrients and mineral absorption, enzyme activity and gutmotility) will be studied in Atlantic salmon (Salmo salar) during Phase 3. The experimental diets composition of the last Phase will be assessed depending on the outcome of the previous experiments (Phase 1 & 2).
    Tailoring Infographics on Water Resources Through Iterative, User-Centered Design: A Case Study in the Peruvian Andes
    Grainger, Sam ; Ochoa-Tocachi, Boris F. ; Antiporta, Javier ; Dewulf, Art ; Buytaert, Wouter - \ 2020
    Water Resources Research 56 (2020)2. - ISSN 0043-1397
    Andean water governance - indigenous knowledge - infographics - Peru - user-centered design - water harvesting

    Effective communication and knowledge sharing across stakeholder groups (e.g., science, government, business, civil society, farmers, and the general public) are essential for more informed water resource management. Visualizations and graphics are powerful tools to engage diverse groups with unfamiliar information. Despite this potential, the design of visuals within applied science settings often does not involve end-user interaction or explicit consideration of their existing knowledge systems, perspective, requirements, and context of use. As a result, products are often difficult for users to understand and contextualize. While user interaction and the development of tailored visualizations is increasingly promoted as a potential remedy, limited empirical evidence exists that shows the potential impact and can guide the development of specific approaches. We piloted an iterative and user-centered design methodology toward the tailoring of infographic-style posters in the context of Peruvian water governance. To test whether tailoring demonstrably improves the perceived effectiveness of products, we designed three products that conveyed similar information but were tailored to three different audiences (an Andean agricultural, urban professional, and urban general). We then compared the tailored posters to those tailored to other audiences by means of interviews and user grading. We found that end-users perceive products that have undergone tailoring as more interesting, clearer, and more useful than products designed without explicit user consideration. Our findings indicate that identifying groups with shared characteristics and requirements is key for effective tailoring. Our research provides empirical evidence to support the incorporation of user-centered design methods in water resource management contexts.

    Hybrid complex coacervate
    Dompé, Marco ; Cedano-Serrano, Francisco Javier ; Vahdati, Mehdi ; Hourdet, Dominique ; Gucht, Jasper Van der; Kamperman, Marleen ; Kodger, Thomas E. - \ 2020
    e-Polymers 12 (2020)2. - ISSN 1618-7229
    Complex coacervation - Nanocomposites - Nanofillers - Poly(N-isopropylacrylamide) - Polyelectrolytes - Underwater adhesion

    Underwater adhesion represents a huge technological challenge as the presence of water compromises the performance of most commercially available adhesives. Inspired by natural organisms, we have designed an adhesive based on complex coacervation, a liquid-liquid phase separation phenomenon. A complex coacervate adhesive is formed by mixing oppositely charged polyelectrolytes bearing pendant thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) chains. The material fully sets underwater due to a change in the environmental conditions, namely temperature and ionic strength. In this work, we incorporate silica nanoparticles forming a hybrid complex coacervate and investigate the resulting mechanical properties. An enhancement of the mechanical properties is observed below the PNIPAM lower critical solution temperature (LCST): this is due to the formation of PNIPAM-silica junctions, which, after setting, contribute to a moderate increase in the moduli and in the adhesive properties only when applying an ionic strength gradient. By contrast, when raising the temperature above the LCST, the mechanical properties are dominated by the association of PNIPAM chains and the nanofiller incorporation leads to an increased heterogeneity with the formation of fracture planes at the interface between areas of different concentrations of nanoparticles, promoting earlier failure of the network-an unexpected and noteworthy consequence of this hybrid system.

    Rainwater harvesting for sustainable agriculture in high water-poor areas in the West Bank, Palestine
    Shadeed, Sameer ; Judeh, Tariq ; Riksen, Michel - \ 2020
    Water 12 (2020)2. - ISSN 2073-4441
    Agricultural rainwater harvesting - Agricultural rainwater harvesting suitability - Agricultural water poverty - GIS - Sustainable agriculture - West bank (Palestine)

    In most arid regions of the world, the increasing agricultural water supply-demand gap jeopardizes sustainable agricultural development and, as such, undermines local food security. In such situations, unconventional water resource practices such as agricultural rainwater harvesting (ARWH) can be potentially used to tackle agricultural water poverty (AWP). This study aims to integrate AWP and agricultural rainwater harvesting suitability (ARWHS) maps to identify locations where ARWH can be of the most benefit to theWest Bank, Palestine. These maps were developed under the GIS environment. The weighted overlay summation process (WOSP), supported by the analytical hierarchy process (AHP), was utilized. Research findings of the AWP map indicate that high to very high AWP covers about 61% of the study area, whereas, the findings of the ARWHS map shows that highly suitable ARWH areas cover 65% of the total study area. Further, 31% of the study area has highly suitable sites for the implementation of proper ARWH techniques. Finally, the combined mapping between the ARWHS map and agricultural lands indicates that high to very high ARWH-suitable areas cover 53% of the rough grazing areas (62% of the entire West Bank area). Thus, the implementation of proper ARWH techniques in such areas is seen to be a sustainable water management option for achieving agricultural sustainability and, accordingly, improved food security in the West Bank, Palestine.

    Freshwater ecoacoustics: Listening to the ecological status of multi-stressed lowland waters
    Lee, Gea H. van der; Desjonquères, Camille ; Sueur, Jérôme ; Kraak, Michiel H.S. ; Verdonschot, Piet F.M. - \ 2020
    Ecological Indicators 113 (2020). - ISSN 1470-160X
    Dissolved oxygen dynamics - Invertebrates - Passive acoustic monitoring - Water quality assessment

    A major challenge in water quality assessment is to identify suitable indicators to monitor and assess the effects of anthropogenic stressors on the ecological status of freshwater ecosystems. Passive acoustic monitoring is a novel approach that could potentially be used to detect invertebrate species and ecological processes such as dissolved oxygen dynamics in freshwater environments. The aim of the present study was to evaluate to what extent sounds can be used for water quality assessment. We performed a field study to relate acoustic indices to the intensity of several stressors, the invertebrate community composition and the dissolved oxygen dynamics in 20 temperate lowland streams and drainage ditches impacted to a varying degree by agricultural activities and discharges from waste water treatment plants. Our results showed that the recorded acoustic patterns were primarily associated with the fluctuation in dissolved oxygen saturation, while specific frequency bands could be related to the sound-producing invertebrate community. We observed that acoustic indices do not allow to detect the adverse effects of anthropogenic stressors on the invertebrate community composition, presumably due to the prevalence of Heteroptera which are relatively insensitive to stressors, but make a lot of sounds. A strong relation between acoustic indices and oxygen fluctuation indicate that passive acoustic monitoring may be used to estimate metabolism in water bodies. We suggest that the next step in freshwater ecoacoustics will be to precisely characterise each source of sound emitted during the processes of primary production, respiration and re-aeration, in order to distinguish these parameters. This may overcome some of the challenges encountered in the estimation of metabolism from diel dissolved oxygen curves.

    Surplus of dietary micronutrients promotes antioxidant defense and improves fin erosions in European seabass (Dicentrarchus labrax) fry
    Kokou, Fotini ; Bastias, Roberto ; Kokkari, Konstantina ; Katharios, Pantelis ; Cotou, Efthimia ; Seimenis, Nikos ; Vasilakis, Manolis ; Papandroulakis, Nikos ; Henry, Morgane ; Rigos, George - \ 2020
    Aquaculture 523 (2020). - ISSN 0044-8486
    Alternative prophylactics - Antioxidant defense - Aquaculture - Minerals - Vitamins

    Dietary micronutrient supplementation can serve as skin health promotor to prevent from natural infections and can be applied to decrease the use of antibacterial agents and their impact on the environment. Such supplementation has indicated anti-inflammatory and antioxidant properties in farmed fish. In this study, dietary supplementation of zinc, selenium, ascorbic acid and niacin, at levels 2 to 3-fold higher than recommended, was evaluated as a measure to promote skin health and antioxidant defense in European seabass, Dicentrarchus labrax, fry. For this purpose, fish survival, growth performance, fin and skin erosions as well as whole-fish antioxidant enzyme activity (catalase, selenium (Se)-independent and dependent glutathione peroxidase) were assessed. Moreover, bacterial load in the rearing water and skin mucus were evaluated to assess the potential of the dietary micronutrient mixture as a preventive from natural infections. A group fed with a diet including these micronutrients at recommended levels served as a control. Surplus of these micronutrients significantly reduced the percentage of fish with eroded fins, while also induced the activity of catalase and Se-dependent glutathione peroxidase. Fish growth and bacterial loads in the water and fish skin mucus were not affected, whereas no skin lesions were observed. Overall, a mineral- and vitamin-supplemented diet at levels higher than recommended seems to act as a promotor of skin health and prevent from fin erosions, potentially through an increase in the antioxidant defense system.

    Analysis of interactions amongst shade trees, coffee foliar diseases and coffee yield in multistrata agroforestry systems
    Durand-Bessart, Clémentine ; Tixier, Philippe ; Quinteros, Alcide ; Andreotti, Federico ; Rapidel, Bruno ; Tauvel, Camille ; Allinne, Clémentine - \ 2020
    Crop Protection 133 (2020). - ISSN 0261-2194
    Central America - Coffea arabica - Disease regulation - Ecological processes - Plant diversity - Structural equation modelling - Trade-off - Tree-shade impact

    In complex coffee-based agroforestry systems, quantifying the impact of shade trees on coffee disease regulation and coffee yield is crucial for improving these systems and designing more sustainable ones. To this end, we analyzed interactions amongst shade trees, coffee plants (cv. Catimor), the coffee foliar disease complex and soil characteristics. We studied systems characterized by 40 variables measured in 60 plots located on three farms (monitored for 2 years) in Nicaragua. These variables characterized six system components grouped in six statistical blocks: shade trees (shade percentage and species abundancy), soil characteristics (fertility), foliar diseases, coffee plant characteristics (age and size), coffee growth and yield. We used partial least square path modelling (PLS-PM), i.e. a structural equation modelling approach used to understand and quantify interactions between the six blocks. Shade trees (mostly the associated shade percentage) had direct positive effects on foliar disease severity and incidence and soil quality, while having negative effects on coffee growth and yield. Soil characteristics (carbon, nitrogen, litter index, water infiltration potential) were negatively correlated with foliar diseases. An excessive shade percentage then had an indirect negative effect on coffee growth and yield due to the increased prevalence of foliar diseases. Finding the optimal shade cover can help reduce foliar diseases and enhance coffee berry production. The ‘dose effect’ of shade cover must also be considered because excessive shade, as well as lack of shade, have negative impacts on coffee growth and yield. Overall, effective shade management requires an analysis of trade-offs between soil quality, disease regulation and yield gains. In conclusion, PLS-PM turned out to be a good tool for studying agroecosystem networks and enabled us to put forward some foliar disease management and coffee yield enhancement guidelines.

    Rooted water collectives: Towards an analytical framework
    Vos, Jeroen ; Boelens, Rutgerd ; Venot, Jean Philippe ; Kuper, Marcel - \ 2020
    Ecological Economics 173 (2020). - ISSN 0921-8009
    Common-pool resources management - Federations - Rooted water collectives - Social movements - Water governance

    This paper presents an analytical framework to identify and understand grassroots water governance practices, which we call ‘rooted water collectives’ (RWC). RWCs can be multi-scalar organizations that engage in common property resources management or multi-scalar social movements that advocate for common property resources governance. The framework, which we open for discussion, scrutinizes (1) the extent to which ‘rooted water collectives’ are ‘grounded’ in the sense they address locally perceived water control problems and resort to water-context embedded meaning, values, identities, belonging and vernacular knowledge; (2) their internal decision-making dynamics; and (3) their effectiveness in achieving impact at multiple scales. It also considers five contextual factors that enable and constrain RWC development. RWC can be deployed as a conceptual lens, but also as an empirical manifestation constituting the object and subject of research. It differs from wide-spread top-down-implemented participatory water management approaches and common property resources management research, in the importance it gives to politics, advocacy and multi-scale social movements. The framework is illustrated with a cursory analysis of four cases: irrigators' federations in Peru; the ‘new water culture’ movement in Spain; collective irrigation in oases in North Africa; and loosely structured networks of irrigation water users in Cambodia.

    Early Pleistocene River Terraces of the Gediz River, Turkey : The role of faulting, fracturing, volcanism and travertines in their genesis
    Maddy, D. ; Veldkamp, A. ; Demir, T. ; Aytaç, A.S. ; Schoorl, J.M. ; Scaife, R. ; Boomer, I. ; Stemerdink, C. ; Schriek, T. van der; Aksay, S. ; Lievens, C. - \ 2020
    Geomorphology 358 (2020). - ISSN 0169-555X
    Early Pleistocene, Turkey - Landscape Evolution - River terraces - Travertine

    Reconstructing and interpreting past hydrological system changes from the Quaternary sediment-landform record presents many challenges especially when trying to establish causality. In such circumstances attempting to isolate individual drivers is perhaps unrealistic and thus inferences are made with respect to the combined influence of multiple controls and constraints. In this paper we seek to interpret the landscape responses recorded in the sediment-landform record of the Early Pleistocene Gediz valley, western Turkey, within the context of interacting geodynamic and hydrodynamic system changes. Our earlier work on the Gediz sequence established the presence of a rich fluvial archive constrained by a comprehensive geochronology from overlying lava flows. Repeated damming of the Gediz valley floor and consequent re-routing of water flow, testifies to a direct connection between fluvial activity and volcanism. This volcanism has been linked to regional tectonic extension with regional uplift promoted as a major driver of the progressive river incision of the Gediz River over the Quaternary. This incision has been punctuated by periods of deposition dictated by sediment and water budgets controlled principally by fluctuating climate and consequent vegetation change. Recently however, the significance of more local fault movements and fracturing has been recognised and here we examine and attempt to quantify these geodynamics in greater detail. In addition, we examine and describe, for the first time, extensive associated travertine deposits. Isotopic analysis of these travertines confirms their thermogenic origin and directly links their creation to the faulting/fracturing, volcanism and the recycling of calcium-rich groundwater. The formation of mounds and sheets extend onto their contemporary valley floors, thus directly connecting the fluvial and travertine archives and allowing linkage between surface and subsurface hydrological change. By utilising both the fluvial and travertine archives a more complex picture of landscape evolution emerges. The youngest terraces (

    Why are cluster farmers adopting more aquaculture technologies and practices? The role of trust and interaction within shrimp farmers' networks in the Mekong Delta, Vietnam
    Joffre, Olivier M. ; Vries, Jasper R. De; Klerkx, Laurens ; Poortvliet, Marijn - \ 2020
    Aquaculture 523 (2020). - ISSN 0044-8486
    Adoption - Farmer clusters - Group farming - Shrimp farming - Trust - Vietnam

    A common avenue to enable adoption of technologies and practices by small-scale producers is by means of farmer clusters. These are achieved by building networks and partnerships between farmers and other actors within the supply chain. This paper examines the role that farmer clusters play in the adoption of practices and technologies by shrimp farmers in Vietnam. Understanding the decisions that lead to adoption is important because these have a key impact on sustainable land use in aquaculture. We report on two complementary studies that test the role of farmer clusters in accessing different sources of knowledge and the trust associated with each of the knowledge sources. First, a survey (N = 193) tested the relationship between cluster membership and adoption, and showed that shrimp farmers who are members of farmer clusters are more likely to adopt three types of pond management practices (i.e. water quality management, feed input, and disease control practices). Furthermore, frequency of interaction with, and trust related to, key stakeholder actors could partly explain this relationship. Second, focus group discussions further zoomed into the dynamics that underlie the adoption of technologies and practices by cluster farmers and non-cluster farmers, respectively. We found that input retailers, buyers and hatcheries were only valued for their input on specific products and issues, but not trusted, as the information always needed being verified through testing by, amongst others, neighbors. Consequently, trust relations with these actors can be described as strongly calculative. Farmer clusters increase trust and tighten relationships between members. As a result, members trust each other when verifying information or sharing knowledge acquired from less trusted sources. On the basis of these results, we argue that reliance on existing farmer networks (i.e. clusters) is a viable tool to improve adoption of sustainable technologies and achieve land use planning objectives. Further implications for research and policy are discussed.

    Comparison of hepatitis E virus sequences from humans and swine, the Netherlands, 2008-2015.
    Hogema, Boris ; Honing-Hakze, R.W. van der; Molier, M. ; Zaaijer, Hans L. ; Poel, W.H.M. van der - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 27 - 27.
    Until the beginning of this century, in the developed world, hepatitis E virus (HEV) was seen as a travellers disease and autochthonous HEV infection was rarely observed. Now a days HEV infections become common and recent studies showed that zoonotic hepatitis E virus genotype 3 infections occur frequently in industrialized countries. Pigs have been shown to be a major reservoir of hepatitis E genotype 3 virus, only the transmission route(s) from pigs to humans are ill-defined. Consumption of undercooked meat products is the likely transmission route however the virus could also spread via surface water or crops. Partly orf 1 and orf 2 sequences of HEV isolates were obtained from individual pigs and from blood donors and hepatitis patients. 372 human samples and at least 10 HEV positive caecum swine samples per year were collected in the Netherlands in 2000 and between 2008 and 2015 and sequenced. All generated HEV sequences from human and pig samples were aligned with a proposed reference set from the literature. In to-tal, 91 HEV ORF1 sequences and 300 HEV ORF2 sequences from pigs, patients and blood donors were included in the analysis. Sequence comparison showed that all sequences were genotype 3 except for six patients (with travel history). HEV gt3c was the most common subgenotype. Whereas the proportion of gt3c significantly increased between 2000 and 2008 it remained constant between 2008 and 2015. Of the circulating HEV subgenotypes, there was no difference observed between the human and the pig isolates. This is compatible with the assumption that HEVs from swine are the major source of HEV infections in humans. Hepatitis E viruses in humans are very likely to originate from pigs, but it is unclear why HEV gt3c has become the predominant subtype in the Netherlands
    Effect of non‐migrating bars on dune dynamics in a lowland river
    Ruijsscher, T.V. ; Naqshband, S. ; Hoitink, A.J.F. - \ 2020
    Earth Surface Processes and Landforms (2020). - ISSN 0197-9337
    As dunes and larger scale bed forms such as bars coexist in rivers, the question arises whether dune dynamics are influenced by interaction with the underlying bed topography. The present study aims to establish the degree in which dune characteristics in two and three dimensions are influenced by an underlying topography dominated by non‐migrating bars. As a case study, a 20km stretch in the Waal River in the Netherlands is selected, which represents a sand‐bed lowland river. At this location, longitudinal training dams (LTDs) have recently been constructed to ensure sufficient navigation depth during periods with low water levels, and to reduce flood risk. By using data covering two‐year‐long periods before and after LTD construction, the robustness of the results is investigated. Before LTD construction, dune characteristics show large variability both spatially and temporally, with dunes being longer, lower, less steep and having a lower lee side angle when they are located on bar tops. The correlation between dune characteristics and the underlying bed topography is disrupted by unsteady conditions for which the dunes are in a state of transition. The bar pattern causes tilting of dune crest lines, which may result from a transverse gradient in bed load sediment transport. As a result of LTD construction, the hydraulic and morphological conditions have changed significantly. Despite this, the main conclusions still hold, which strengthens the validity of the results.
    E-DATA: A Comprehensive Field Campaign to Investigate Evaporation Enhanced by Advection in the Hyper-Arid Altiplano
    Suárez, Francisco ; Lobos, Felipe ; La Fuente, Alberto De; Vilà-guerau De Arellano, Jordi ; Prieto, Ana ; Meruane, Carolina ; Hartogensis, Oscar - \ 2020
    Water 12 (2020)3. - ISSN 2073-4441
    In the endorheic basins of the Altiplano, water is crucial for sustaining unique ecological habitats. Here, the wetlands act as highly localized evaporative environments, and little is known about the processes that control evaporation. Understanding evaporation in the Altiplano is challenging because these environments are immersed in a complex topography surrounded by desert and are affected by atmospheric circulations at various spatial scales. Also, these environments may be subject to evaporation enhancement events as the result of dry air advection. To better characterize evaporation processes in the Altiplano, the novel Evaporation caused by Dry Air Transport over the Atacama Desert (E-DATA) field campaign was designed and tested at the Salar del Huasco, Chile. The E-DATA combines surface and airborne measurements to understand the evaporation dynamics over heterogeneous surfaces, with the main emphasis on the open water evaporation. The weather and research forecasting model was used for planning the instruments installation strategy to understand how large-scale air flow affects evaporation. Instrumentation deployed included: meteorological stations, eddy covariance systems, scintillometers, radiosondes and an unmanned aerial vehicle, and fiber-optic distributed temperature sensing. Additional water quality and CO2 fluxes measurements were carried out to identify the link between meteorological conditions and the biochemical dynamics of Salar del Huasco. Our first results show that, in the study site, evaporation is driven by processes occurring at multiple spatial and temporal scales and that, even in the case of available water and energy, evaporation is triggered by mechanical turbulence induced by wind. View Full-Text
    Monitoring effecten zandsuppletie Leuvenumse beek 2019
    Verdonschot, Ralf ; Verdonschot, Piet - \ 2020
    Wageningen : Wageningen Environmental Research (Notitie Zoetwatersystemen, Wageningen Environmental Research ) - ISBN 9789463953481 - 47
    In de Leuvenumse beek wordt vanaf 2014 het suppleren van zand als beekherstelmaatregel toegepast door Waterschap Vallei en Veluwe en Natuurmonumenten. Omdat over deze relatief nieuwe maatregel nog niet veel kennis voorhanden is, worden sindsdien de hydromorfologische en biologische ontwikkelingen gevolgd. In 2019 zijn metingen verricht aan het dwarsprofiel van de beek en de geleidbaarheid van het water. Het dwarsprofiel van de beek is ingemeten om zo de veranderingen in bodemhoogte in beeld te krijgen die in gang zijn gezet door het uitvoeren van de maatregelen. Deze metingen lopen al vanaf 2014. Net zoals 2018 was 2019 een droog jaar dat gekenmerkt werd door lage afvoeren in het projectgebied. Ter hoogte van de A28 stond de beek voor het tweede jaar op rij langdurig droog. Metingen aan de dwarsprofieltransecten lieten nog steeds een duidelijke bodemophoging zien ten opzichte van 2014. Wel waren pleksgewijs kleine veranderingen opgetreden, vooral in de vorm van verbreding en afvlakking van de bedding en verondieping. Erosie en sedimentatieprocessen van een grotere omvang worden pas weer verwacht als de afvoer van de beek aanzienlijk toeneemt. Met behulp van continu-dataloggers is geprobeerd inzicht te krijgen in de effecten van de maatregelen op de stofstromen die vanuit bovenstrooms het projectgebied bereiken, waarbij geleidbaarheid als indicator is gebruikt om pieken van stoffen en de uitdoving hiervan te meten in een situatie met en zonder overstromingsvlaktes langs de beek. De geleidbaarheidsmetingen lieten zien dat piekafvoeren een toename van de geleidbaarheid tot gevolg hadden, wat een indicatie is van de toevoer van stoffen van bovenstrooms door in- en afspoeling van aanliggende gronden. Verder was het effect van een calamiteit in de vorm van een mestlozing duidelijk terug te zien als een piek in de geleidbaarheid. De toename van geleidbaarheid bleek niet af te zwakken over een traject van 1.7 kilometer, ook niet na passage van de overstromingsvlaktes langs de beek wat aangeeft dat daar geen sterke interactie lijkt op te treden door bijvoorbeeld binding aan organisch materiaal. Dit wil zeggen dat wat er van bovenstrooms wordt aangevoerd doordringt in het bostraject. Hoe deze invloed doorwerkt op de ecologische waarden in de beek is niet duidelijk. Een groot nadeel van het gebruik van de geleidbaarheid is namelijk dat het onbekend blijft welke stoffen verantwoordelijk zijn voor de gemeten toename. Hiervoor moet in meer detail en met een hoge meetfrequentie de waterchemie bestudeerd worden rond een afvoerpiek.
    Live barriers and associated organic amendments mitigate land degradation and improve crop productivity in hillside agricultural systems of the Ecuadorian Andes
    Caulfield, Mark ; Groot, Jeroen C.J. ; Fonte, Steven J. ; Sherwood, Stephen ; Oyarzun, Pedro ; Borja, Ross Mary ; Dumble, Sam ; Tittonell, Pablo - \ 2020
    Land Degradation and Development (2020). - ISSN 1085-3278
    Andean alder - Andes - canary grass - Ecuador - erosion - nutrient depletion

    Land degradation caused by erosion and nutrient depletion in the Andes poses serious existential threats to small-scale farming. Although the potential of hedgerows to decrease water erosion is well recognised, their potential dual-use as a source of organic amendments to supplement farmer inputs is much less studied. The objective of this investigation was therefore to explore locally developed options for hedgerows that address these twin challenges. Experimental plots were installed to assess water erosion control by hedgerows and the effect of organic amendments harvested from the hedgerows on soil productivity, soil moisture, and soil fertility over the course of 2 years and three crop cycles (two of barley and one of rye). The experiment was conducted in two sites within the community at distinct elevations and associated biophysical contexts. At each site, four treatments were established, comparing a control treatment versus three types of hedgerows: (a) Andean alder, (b) canary grass strips, and (c) mixed canary grass and Andean alder. Results demonstrated that hedgerows and associated organic inputs comprised canary grass, and mixed canary grass and Andean alder reduced water erosion by 50–60% and increased biomass production by up to 1.1 Mg ha−1 and grain yield by up to 0.5 Mg ha−1. We conclude that although hedgerows are unlikely to produce sufficient quantities of organic resources to satisfy all nutrient input requirements, their potential to decrease erosion and supplement existing organic matter inputs indicates that they should be strongly considered as an option for improved agricultural management within this and similar resource constrained contexts.

    Effect of Use of Treated Urban Wastewater, Seawater and Clinoptilolite-Zeolite on Yield of Sorghum
    Ghassemi Sahebi, Fakhroddin ; Mohammadrezapour, O. ; Delbari, M. ; KhasheiSiuki, A. ; Ritzema, H.P. ; Cherati, A. - \ 2020
    Agricultural Water Management 234 (2020). - ISSN 0378-3774
    Under conditions of water shortage, utilizing unconventional waters, such as treated urban wastewater and/or seawater, in combination with soil amendments such as zeolite, can reduce the harmful effects of drought stress on crop yield. To investigate the agronomic and physiological effects of a mix of water qualities and soil treatments on sorghum, a randomized split-plot research was conducted at Gharakheil agricultural research station, Ghaemshahr, Northeast Iran. Six combinations of water qualities and three different use of soil amendments were tested over two seasons in 2016 and 2017. The water quality treatments with increasing salinity included well water as the control (W1); 75 % well water and 25 % seawater (W2); 25 % well water and 75 % seawater (W3); 100 % treated urban wastewater alternating with 100 % seawater (W4); 50 % seawater and 50 % treated urban wastewater (W5) and 100 % treated urban wastewater (W6). The soil amendments were no-zeolite as the control (Z1) and calsic (Z2) and potasic (Z3) zeolite. With increasing salinity, the forage yield decreased significantly. Maximum and minimum forage yield were respectively 129.6 ton.ha−1 inW6-Z2 in 2016 and 46.9 ton.ha−1 in W3-Z1 in 2017. Irrigation Water Use Efficiency (IWUE) was the highest with the treated urban wastewater in combination with zeolite. All six combinations (W4-Z2, W4-Z3, W5-Z2, W5-Z3, W6-Z2 and W6-Z3) had significantly higher IWUEs (range 2.0–2.4) compared to the control (IWUE = 1.7) and the other soil and water treatments. The combinations of 75 % seawater and no zeolite had by far the lowest IWUE (range 1.1–1.7). The same trends were observed for the Leaf Area Index (LAI) and leaf and stem protein. The use of saline sea water increased the soil salinity levels significantly, but the levels were still well below the FAO threshold values for yield reduction. Overall, we can recommend use of treated wastewater in combination with calsic zeolite soil amendment as the combination that had the best effect on crop yield, IWUE, LAI and leaf and stem protein for sorghum production under the conditions of north of Iran.
    Elevated viscosities in a simulated moving bed for γ-aminobutyric acid recovery
    Schultze-Jena, A. ; Boon, M.A. ; Vroon, R.C. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2020
    Journal of Separation Science (2020). - ISSN 1615-9306
    chromatography - concentration profile - productivity - simulated moving bed - viscosity

    Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.

    Comparative Life-Cycle Assessment of Aquifer Thermal Energy Storage Integrated with in Situ Bioremediation of Chlorinated Volatile Organic Compounds
    Ni, Zhuobiao ; Wang, Yue ; Wang, Yafei ; Chen, Shaoqing ; Xie, Manxi ; Grotenhuis, Tim ; Qiu, Rongliang - \ 2020
    Environmental Science and Technology 54 (2020)5. - ISSN 0013-936X - p. 3039 - 3049.

    Due to the increasing need for sustainable energy and environmental quality in urban areas, the combination of aquifer thermal energy storage (ATES) and in situ bioremediation (ISB) has drawn much attention as it can deliver an integrated contribution to fulfill both demands. Yet, little is known about the overall environmental impacts of ATES-ISB. Hence, we applied a life-cycle assessment (LCA) to evaluate the environmental performance of ATES-ISB, which is also compared with the conventional heating and cooling system plus ISB alone (CHC + ISB). Energy supply via electricity is revealed as the primary cause of the environmental impacts, contributing 61.26% impacts of ATES-ISB and 72.91% impacts of CHC + ISB. Specifically, electricity is responsible for over 95% of water use, global warming potential, acidification potential, and respiratory inorganics, whereas the production of the biological medium for bioremediation causes more than 85% of the eco- and human toxicity impacts in both cases. The overall environmental impact of ATES-ISB is two times smaller than that of CHC + ISB. Sensitivity analysis confirms the importance of electricity consumption and electron donor production to the environmental impacts in both energy supply and bioremediation. Thus, future studies and practical applications seeking possible optimization of the environmental performances of ATES-ISB are recommended to focus more on these two essential elements, e.g., electricity and electron donor, and their related parameters. With the comprehensive LCA, insight is obtained for better characterizing the crucial factors as well as the relevant direction for future optimization research of the ATES-ISB system.

    Effects of exchanging lactose for fat in milk replacer on ad libitum feed intake and growth performance in dairy calves
    Berends, H. ; Laar, H. van; Leal, L.N. ; Gerrits, W.J.J. ; Martín-Tereso, J. - \ 2020
    Journal of Dairy Science (2020). - ISSN 0022-0302
    calf - fat - growth - lactose - milk replacer

    The recent trend in the dairy industry toward ad libitum feeding of young calves merits reconsideration of calf milk replacer (CMR) formulations. Additionally, feed intake regulation in young calves provided with ad libitum milk and solid feeds is insufficiently understood. This study was designed to determine the effect of exchanging lactose for fat in CMR on voluntary feed intake and growth performance. Lactose was exchanged for fat on a weight/weight basis, resulting in different energy contents per kilogram of CMR. Thirty-two male calves (1.7 ± 0.12 d of age, 47.6 ± 0.83 kg of body weight) were assigned to 1 of 16 blocks based on arrival date. Within each block, calves were randomly assigned to 1 of 2 treatments. The experimental period was divided into 4 periods. In period 1, until 14 ± 1.7 d of age, calves were individually housed, restricted-fed their assigned CMR treatments at 2.5 to 3 L twice daily, and provided with unlimited access to water, chopped straw, and starter. In period 2, calves were group-housed with 8 calves per pen and received ad libitum access to their assigned CMR treatments, starter feed, chopped wheat straw, and water. During period 3, from 43 until 63 d of age, calves were weaned by restricting CMR allowance in 2 steps, maintaining access to all other feeds. All calves were completely weaned at d 64 of age and were monitored until 77 d of age (period 4). Measurements included the intake of all dietary components, body weight gain, and a selection of blood traits. Increasing fat content at the expense of lactose decreased CMR intake by 10%, whereas total calculated metabolizable energy intake and growth remained equal between treatments. Total solid feed (starter and straw) consumption was not affected by CMR composition. These data indicate that calves fed ad libitum regulate their CMR intake based on energy content. High-fat CMR increased plasma phosphate, nonesterified fatty acids, triglycerides, and bilirubin, whereas plasma glucose remained unchanged. Despite the limited animal numbers in the present experiment, there was a significant decrease in the total number of health events (mainly respiratory) requiring therapeutic intervention and in the total number of therapeutic interventions in calves fed high-fat CMR. Calves appeared to consume CMR based on energy content, with a difference in ad libitum intake proportional to the difference in energy content of the CMR, maintaining equal body weight gain and solid feed intake.

    Rooftop systems for urban agriculture
    Appolloni, Elisa ; Orsini, Francesco ; Stanghellini, Cecilia - \ 2020
    In: Achieving sustainable urban agriculture / Wiskerke, H., London : Burleigh Dodds Science Publishing Limited (Achieving sustainable urban agriculture ) - ISBN 9781786763167 - p. 123 - 142.
    Urban population growth, consequent competition in land use, climate change and lack of productive resources are some of the problems that are currently making necessary a new form of agriculture free from soil exploitation and able to ensure food security to urban dwellers in the most sustainable way. Rooftop farming is a form of building-base agriculture that may help to address not only global nutritional uncertainty, but also social, environmental and economic issues such as social exclusion, heat island effect, storm water damages and urban poverty. This chapter describes the forms, architecture, design elements and management of rooftop farming, as well as presenting case studies from around the world. Finally, the chapter looks ahead to future research trends in this area.
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