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Our study suggests the possibility for transformational change in the productivity and risk profile of some of India's rainfed cropping systems. In the semi-arid regions of Southern India, farmers traditionally crop sorghum or chickpea on Vertisols during the post-rainy season, keeping the fields fallow during the rainy season. This practice avoids land management problems, but limits the potential for crop intensification to increase systems productivity. A long-term (15 year) experiment at ICRISAT demonstrated that cropping during the rainy season is technically feasible, and that grain productivity of double cropped sorghum + chickpea (SCP–SCP) and mung bean + sorghum (MS–MS) sequential systems were higher than their conventional counterparts with rainy season fallow, i.e. fallow + post-rainy sorghum (FS–FS) and fallow + post-rainy chickpea (FS–FCP). Without N application, mean grain yield of post-rainy sorghum in the MS–MS system was significantly greater (2520 kg ha−1 per two-year rotation) than in the FS–FS system (1940 kg ha−1 per two-year rotation), with the added benefit of the mung bean grain yield (1000 kg ha−1 per two-year rotation) from the MS–MS system. In the SCP–SCP system the additional grain yield of rainy sorghum (3400 kg ha−1 per two-year rotation) ensured that the total productivity of this system was greater than all other systems. Double cropping MS–MS and SCP–SCP sequential systems had significantly higher crop N uptake compared to traditional fallow systems at all rates of applied nitrogen (N). The intensified MS–MS and SCP–SCP sequential systems without any N fertilizer applied recorded a much higher median gross profit of Rs. 20,600 (US $ 375) and Rs. 15,930 (US $ 290) ha−1 yr−1, respectively, compared to Rs. 1560 (US $ 28) ha−1 yr−1) with the FS–FS system. Applying 120 kg of N ha−1 considerably increased the profitability of all systems, lifting median gross profits of the sorghum + chickpea system over Rs. 60,000 (US $ 1091) ha−1 yr−1 and the conventional system to Rs. 20,570 (US $ 374) ha−1 yr−1. The gross profit margin analysis showed that nitrogen is a key input for improving productivity, particularly for the double cropping systems. However, traditional systems are unviable and risky without N application in the variable climates of the semi-arid tropics. Together, our results show that on Vertisols in semi-arid India, double cropping systems increase systems’ productivity, and are financially more profitability and less risky than traditional fallow post-rainy systems while further benefits can be achieved through fertilizer application.

‘Verbinding’ is het sleutelwoord van Louise Fresco, de kersverse bestuursvoorzitter van Wageningen UR. Ze wil nieuwe manieren vinden om de samenleving te betrekken bij de ontwikkeling van kennis. ‘Het is mijn droom maatschappelijke discussies vlot te trekken die nu worden lamgelegd door angst, weerstanden en complotgevoelens.’

We describe and analyse how large herbivores strongly diminished a woody vegetation, dominated by the unpalatable shrub Sambucus nigra L. and changed it into grassland. Density of woody species and cover of vegetation were measured in 1996, 2002 and 2012 in the grazed Oostvaardersplassen. In 2002 and 2012 we also measured density and cover in an ungrazed control site. In 2002 we measured intensity of browsing and bark loss of Sambucus shrubs in the grazed and control sites. In the grazed site the density of Sambucus and Salix spp. declined significantly between 1996 and 2012, and large areas changed into grassland. In the control site the density of Sambucus increased significantly during this period, the density of Salix spp. did not change, and the vegetation consisted of a mixture of woody species and a field layer dominated by tall herbs. In 2002 and 2012 the percentages of dead Sambucus shrubs were significantly higher in the grazed site than in the control site. In 2002 the percentages of twigs browsed and ring barked stems of Sambucus shrubs were significantly higher in the grazed site than in the control site. Our results show that debarking caused mature Sambucus shrubs to die, but that heavy browsing may have helped this process. Our results also point to a significant neighbour effect on the break down of Sambucus, suggesting that Aggregational Resistance and Associational Palatability were both active. Essential conditions for the break down of this woody vegetation were the presence of large herbivores, the low ratio between the areas of summer and winter feeding habitats and the competition amongst herbivores. Browsing may have been responsible for seedling death, as seedlings were found only in the control site and not on the old and newly established grasslands in the grazed site.

In een academische wereld die steeds competitiever wordt, willen we graag weten wat ‘de beste’ universiteit is. Verschillende rankings bedienen ons op onze wenken, waaronder Times Higher Education, Sjanghai, QS en Leiden. De kritiek op die lijsten is echter niet mals, ook omdat universiteiten graag selectief shoppen in de resultaten. Toch kunnen we niet om ze heen, meent informatiespecialist Wouter Gerritsma.

To increase the inhibitory effect of soil-incorporated cover crop residues on germination and early growth of weeds, the allelochemical content of the cover crop at the time of soil incorporation should be maximal. We investigated whether mechanical damaging in spring induced the production of allelochemicals in late-summer sown lucerne, winter rye and winter oilseed rape. Allelopathic activity and biomass of intact cover crop plants were determined throughout spring, and mechanically damaged plants were monitored till 14 days after wounding. Allelopathic activity was determined directly by lettuce seedling bioassays (lucerne and winter rye) or indirectly by glucosinolate quantification (winter oilseed rape). During spring, the allelopathic activity per unit biomass of intact plants showed a gradual decline for winter rye and lucerne, and a steep decline at the onset of flowering for winter oilseed rape. All cover crop species attained the highest allelopathic activity per unit area at the end of the sampling period as the increase in biomass surpassed the decline in allelopathic activity per unit biomass. Although mechanical wounding enhanced the allelopathic activity per unit biomass of all three species, the effect was only minor and often just sufficient to compensate for the loss in biomass resulting from wounding. This study therefore indicates that the best option for maximizing the inhibitory effect is to incorporate residues of intact cover crops as late as possible.

This paper describes the year-over-year improvement of the nitrogen (N) efficiency in a prototype mixed farm system through the implementation of a coherent set of ecotechnological adjustments. This farm, the former APMinderhoudhoeve, was located on a marine clay loam soil in Oostelijk Flevoland, the Netherlands, reclaimed from the sea in the late 1950s. The designed farm structure was representative for the Dutch soil-bound agriculture in the late 1990s in terms of food crops’ choice and average level of milk production per ha of farmland. Key management strategies were the inclusion of grass-clover leys in the 7-year crop rotation, restricted grazing of the dairy herd and protein-poor and fibre-rich cattle diets including cereal straw. The farm components animal-manure-soil-crop were analysed in-depth in order to evaluate N flows and soil organic matter (SOM) dynamics at the farm system level, covering a period of six years. In its final experimental state, farm N use efficiency, expressed as the proportion of purchased crop fertilizers and cattle feed that was sold as exported products (crops, milk and cattle), was as high as 73%, Besides, total environmental losses were as low as 42kg N ha−1 yr−1. A scenario analysis revealed that these losses could be further minimized to 30kg N ha−1 yr−1 in the stabilization phase, of which one-third as leached nitrate and a somewhat higher fraction as volatilized ammonia. The remaining losses represented mainly denitrified harmless N2 from the stored animal slurry and farmyard manure. Soil N accumulated at an average rate of 89kg N ha−1 yr−1, whereas SOM showed a positive trend but with fluctuations from year to year which were negatively related to the annual rainfall amount. Despite the lowered protein content in the cow diets, average annual milk production increased from 8100 tot 8700kg cow−1. This could be mainly ascribed to a lower cow replacement rate due to less animal health problems, leading to an increased average lactation number of the dairy herd. Overall, the obtained environmental side effects on the prototype farm in its final experimental state were already below the targets set by the European Union with respect to the Nitrate Directive for the year 2020. It is concluded that when the best ecotechnological means are combined in a balanced mixed farm system a multiple win situation is attained in terms of food production capacity, cattle health and environmental quality.

In 1992 bracht de Wetenschappelijke Raad voor het regeringsbeleid het rapport Grond voor Keuzen uit, een verkenning naar de mogelijkheden voor de Europese landbouw en de realisatie van verschillende maatschappelijke doelen. In dit rapport schetst de Raad beelden voor het optimale grondgebruik in de Europese landelijke gebieden. Afhankelijk van de vier scenario’s die de Raad presenteerde, kon het pesticidengebruik worden teruggebracht met 40 tot 80%, de emissie met 50 tot 70%, de kosten minimaal worden gehalveerd en het areaal in gebruik voor landbouw met 30 tot 50%. Dat betekent dat er iets te kiezen was, zo concludeerde de Raad indertijd. Er is de twintig jaar daarna veel veranderd, en dus is het tijd om de studie van toen, weliswaar veel minder gedetailleerd, in het licht van dit afscheidssymposium van dr Jaap Kuper als rentmeester van het Kroondomein en groot pleitbezorger van natuur en biodiversiteitsherstel, te actualiseren.

The emerging debate on the climate impact of food is expected to result in the carbon labelling of food in the future. As yet, consumer responses to carbon labels are not well researched. A real life experiment was developed to study consumer responses to new carbon labels for food. A ‘light’ and a ‘comprehensive’ carbon labelling regime were stepwise introduced into the food practice of ‘having lunch in a canteen’. The resulting shifts in the behaviour and attitudes of regular canteen visitors were measured with the use of both quantitative and qualitative methods. Despite their overall positive attitude towards climate change policies, the canteen visitors show clear resistance to some of the changes suggested, especially when new courses of action run counter to the dynamics of the existing routinised practice. Using practice theory as our reference, we discuss the role of information provision next to other policy instruments for facilitating behavioural changes towards low carbon food consumption.

Despite great concerns to meet the ever growing food demand in the past, megatrends in agriculture has resulted in growing food availability per person and reducing adverse environmental impact. The bleak future that is portrayed to secure sufficient food for all can be resolved with increased ecological literacy and compliance with production ecological approaches. Yet, these opportunities may not be easily attained, certainly so with dominating dogmatic views on agro-ecological practices that do not comply with or even reject basic ecological principles.

Aalt Dijkhuizen baarde in 2012 veel opzien toen hij luid hoorbaar verkondigde dat de agrarische producties omhoog moeten vanwege de wereldwijde voedselbehoefte. Vanuit agrarische kringen ging applaus op, dierenwelzijnsorganisaties hadden felle kritiek. Beide reacties kan Dijkhuizen zich voorstellen. Alleen het onfatsoen waarmee sommige NGO’s en hun sympathisanten reageerden, vindt hij ongehoord. Op 1 maart 2014 stopt Dijkhuizen als voorzitter van de raad van bestuur van Wageningen UR. In dit interview blikt hij terug op twaalf jaar voorzitterschap.

The gene coding for xylose isomerase from the thermophilic bacterium Fervidobacterium gondwanense was cloned and overexpressed in Escherichia coli. The produced xylose isomerase (XylA), which closely resembles counterparts from Thermotoga maritima and T. neapolitana, was purified and characterized. It is optimally active at 70 degrees C, pH 7.3, with a specific activity of 15.0 U/mg for the interconversion of glucose to fructose. When compared with T. maritima XylA at 85 degrees C, a higher catalytic efficiency was observed. Divalent metal ions Co2+ and Mg2+ were found to enhance the thermostability.

Het boek en de ontwerpfilosofie Cradle to Cradle van de Amerikaan William McDonough en de Duitser Michael Braungart mogen zich verheugen in een zeer brede belangstelling. Steden proberen nieuwe wijken volgens het C2C-concept te bouwen, de rijksoverheid vraagt zich af hoe C2C in het beleid kan worden ingepast en de beide auteurs krijgen van diverse universiteiten eredoctoraten aangeboden. Maar wat is de 'Van wieg tot wieg' filosofie nu eigenlijk precies? En wat kan het betekenen in het kader van een ontwikkeling naar een meer duurzame samenleving?

Commercial potato minituber production systems aim at high tuber numbers per plant. This study investigated by which mechanisms planting density (25.0, 62.5 and 145.8 plants/m2) of in vitro derived plantlets affected minituber yield and minituber number per plantlet. Lowering planting density resulted in a slower increase in soil cover by the leaves and reduced the accumulated intercepted radiation (AIR). It initially also reduced light use efficiency (LUE) and harvest index, and thus tuber weights per m2. At the commercial harvest 10 weeks after planting (WAP), LUE tended to be higher at lower densities. This compensated for the lower AIR and led to only slightly lower tuber yields. Lowering planting density increased tuber numbers per (planted) plantlet in all grades. It improved plantlet survival and increased stem numbers per plant. However, fewer stolons were produced per stem, whereas stolon numbers per plant were not affected. At lower densities, more tubers were initiated per stolon and the balance between initiation and later resorption of tubers was more favourable. Early interplant competition was thought to reduce the number of tubers initiated at higher densities, whereas later-occurring interplant competition resulted in a large fraction of the initiated tubers being resorbed at intermediate planting densities. At low planting densities, the high number of tubers initiated was also retained. Shortening of the production period could be considered at higher planting densities, because tuber number in the commercial grade > 9 mm did not increase any more after 6 WAP.

While global food availability increased by 27% per person over the past four decades, it decreased by 12% in Sub-Saharan Africa (SSA). This paper explores the role of technology use on agricultural development to understand the ever widening gap of SSA with other global regions. It looks into land (i.e., yield) and labour productivity, the relation between technology use and yield stability and, the environmental implications of input use. Ways and means are discussed as to what innovative technologies could close the gap, taking complex mixed farming systems as an entry point that account for 90% of Africa's agriculture.

In this study, we show that introduction of human N-acetylglucosaminyltransferase (GnT)-III gene into tobacco plants leads to highly efficient synthesis of bisected N-glycans. Enzymatically released N-glycans from leaf glycoproteins of wild-type and transgenic GnT-III plants were profiled by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in native form. After labeling with 2-aminobenzamide, profiling was performed using normal-phase high-performance liquid chromatography with fluorescence detection, and glycans were structurally characterized by MALDI-TOF/TOF-MS and reverse-phase nano-liquid chromatography-MS/MS. These analyses revealed that most of the complex-type N-glycans in the plants expressing GnT-III were bisected and carried at least two terminal N-acetylglucosamine (GlcNAc) residues in contrast to wild-type plants, where a considerable proportion of N-glycans did not contain GlcNAc residues at the nonreducing end. Moreover, we have shown that the majority of N-glycans of an antibody produced in a plant expressing GnT-III is also bisected. This might improve the efficacy of therapeutic antibodies produced in this type of transgenic plant.

This chapter focuses on the subject of ecoregional research for development. The character of international agricultural research has changed profoundly in the last decades of the twentieth century. This can be illustrated by developments within the Consultative Group on International Agricultural Research (CGIAR). The need for a support of comprehensive systems' analysis of the CGIAR agenda required new research; therefore, the development agencies of the Dutch and Swiss governments initiated the Ecoregional Methodology Fund in 1995 as part of its development-oriented activities. This Fund was expected to support the development of new methodological tools for research that is ecoregional in scope with the intention of promoting new approaches to natural resource management and rural development in ecoregions. This chapter summarizes and discusses the accomplishments and the future challenges of Ecoregional Methodology Fund. In doing so, the chapter presents a sketch of the changing social and political environment in which the work has been done, ranging from the UN Millennium Development Goals (MDGs) to the strategy of the CGIAR Science Council and the Gleneagle summit. It also elaborates the changing role of research, vis-a-vis the policy cycle. Implications for research, including new forms of interaction, design of operational tools, and new forms of education and communication are also discussed in the chapter.

An increased intake of soybean oil at the expense of an iso-energetic amount of non-structural carbohydrates reduces the apparent digestibility of fibre in horses. Literature data indicate that bile acids and linoleic acid (C18:2 n ¿ 6) may inhibit growth of pure cultures of microorganisms. In the present series of experiments, the hypotheses tested were that after extra fat intake as soybean oil more bile acids and linoleic acid would enter the caecum which depresses microbial growth and thus also fibre fermentation. Based on measurements of faecal bile acid excretion in horses, no evidence was obtained for a higher influx of bile acids into the caecum after iso-energetic substitution of dietary soybean oil for starch plus glucose. When dietary palm oil was replaced by soybean oil, which caused a six-fold increase in linoleic acid intake, fibre digestibility in horses was not lowered. The infusion of linoleic acid into the caecum of fistulated ponies increased apparent fibre digestibility. It is concluded that the results of the three experiments disprove the hypotheses tested.

2 ingezonden brieven, waarin het standpunt voor de teelt en het gebruik van biobrandstoffen wordt geplaatst tegenover een tegenstandpunt

This study quantifies the effect of oil layer thickness on entrainment and dispersion of oil into seawater, using a plunging jet with a camera system. In contrast to what is generally assumed, we revealed that for the low viscosity "surrogate MC252 oil" we used, entrainment rate is directly proportional to layer thickness. Furthermore, the volume of stably suspended small oil droplets increases with energy input (plunge height) and is mostly proportional to layer thickness. Oil pre-treated with dispersants (dispersant-oil ratio ranges from 1:50 to 1:300) is greatly entrained in such large amounts of small droplets that quantification was impossible with the camera system. Very low interfacial tension causes entrainment by even minor secondary surface disturbances. Our results indicate that the effect of oil layer thickness should be included in oil entrainment and dispersion modelling.

In de periferie van de VN-klimaatconferentie, van 30 november tot en met 11 december in Parijs, wemelt het van de bijeenkomsten en side-events. Ook Wageningen UR levert haar bijdrage aan dit marktplein van de klimaatwetenschap. Enkele tientallen wetenschappers en studenten trekken naar Parijs om hun boodschap te verkondigen. Op deze pagina’s een kleine greep.

Vier buurtstichtingen in Hoensbroek hebben interesse getoond om gedeeltelijk verantwoordelijkheid te nemen voor de openbare groene ruimte. De buurtstichtingen ziet de gemeente als brug tussen overheid en burgers. De inhoud van dit rapport is interessant voor andere buurtstichtingen om eigen initiatieven vorm te geven.

Farming systems in the Costa Chica region in Mexico face limitations linked to low yields and soil fertility degradation. Several alternative maize-based cropping systems have been proposed to improve current limitations. These field-level options need to be evaluated at farm level in order to assess their feasibility, taking into account input requirements, contributions to self-sufficiency in food and long-term soil fertility, and the availability of labor. In this study, we defined four scenarios to explore consequences of changes in current farming systems for eight typical farms in the region; the first two scenarios comprised redressing current imbalances in crop nutrition and organic matter (OM) supply, respectively, and the last two scenarios explored high fertilizer input and animal husbandry. Farms responded in different ways to the various options depending on available land, current soil quality, current cropping systems and presence of livestock. Improvements in crop nutrition based on mineral fertilizers increased family income but only had substantial effects on soil OM (SOM) balances when fertilizer rates were double the amount currently subsidized. Addition of organic fertilizers resulted in positive effects on SOM balance, but with often strong trade-offs with family income due to costs of acquisition, transport and application. Animals played an important role in increasing SOM balances, but had relatively little effect on improving family income. The results demonstrated that improvements in family income and SOM balance at farm scale were feasible but that without more fundamental system changes trade-offs between short-term yield increases and longer-term soil fertility increases should be expected. The results highlight the need for policies that take into account farm-specific differences in crop and livestock intensification opportunities.

Interview met Gerlinde van Vilsteren (CBBE) en Petra Koenders (CoE BBE). Het bedrijfsleven, zeker het midden- en kleinbedrijf, is de motor achter de biobased economy. Willen ze succesvol opereren, dan is kennis een sleutelfactor en zullen bedrijven en onderzoeks- en onderwijsinstellingen onderling nauwer samen moeten gaan werken. Dat gebeurt onder de vlag van het Centre for Biobased Economy (CBBE).

Vier buurtstichtingen in Hoensbroek hebben interesse getoond om gedeeltelijk verantwoordelijkheid te nemen voor de openbare groene ruimte. De buurtstichtingen ziet de gemeente als brug tussen overheid en burgers. De inhoud van dit rapport is interessant voor andere buurtstichtingen om eigen initiatieven vorm te geven.

Susceptibility of potato varieties for tobacco rattle virus (TRV) and sensitivity for spraing in potato tubers both depend on the interaction between cultivar and virus strain. Of the six potato cultivars investigated in this research, cultivar Santana was the most susceptible to TRV, the cultivars Roxy and Saturna were the least susceptible. In general, potato cultivars were most susceptible to the virus type transmitted by P. pachydermus and least for the virus type transmitted by T. primitivus. Potato cultivars showed a large difference in susceptibility for various TRV types. This was the most obvious for cultivar Wilja. Wilja showed high virus concentrations (susceptible) for a virus type transmitted by P. pachydermus but very low concentrations (resistant) for virus types transmitted by P. teres and T. primitivus. Cultivar Santana was the most sensitive for spraing, cultivar Wilja was the least sensitive. As Wilja is very susceptible to the virus strain transmitted by P. pachydermus, but is insensitive for spraing caused by this strain, this cultivar is called a "symptomless carrier" for this type of TRV. All six investigated potato cultivars can pass on TRV via seed potatoes to the next generation (secondary infection) but the degree of this virus transmission depended on potato cultivar, virus type and the interaction between cultivar and TRV and seems to be connected with the susceptibility for TRV. Transmission of the TRV type of P. pachydermus via seed potatoes was the highest in the cultivars Santana and (to a lesser degree) Sante¿ and in cultivar Wilja. Even in the very sensitive cultivar Santana, TRV was passed on via seed potatoes. The prevailing theory that in sensitive potato cultivars TRV particles are immobilized in the necrotic 'spraing' tissue, therefore seems to be inaccurate. Since virus-vector combinations show specific interactions with cultivars, it is recommended to do potato variety research in several fields with different viruliferous trichodorid species

Using microsatellites, we investigated population structure and gene flow of the short-lived, wind-dispersed plant species Hypochaeris radicata in a fragmented agricultural landscape where more than 99% of the nutrient-poor grasslands have disappeared over the last century. We sampled populations in the few remaining high density populations in conservation areas, as well as individuals that occurred, with lower densities, in linear landscape elements, at two spatial scales. In a re-inventory of the landscape, after 3 years, both extinctions and colonizations of populations were observed. Contrary to expectations, no differences in genetic diversity between high and low density populations were observed. Both types of populations had relatively high levels of diversity. Overall genetic differentiation (¿) was 0.04 and significantly different from zero (P

A spatially explicit model describing saprophytic colonization of dead cyclamen leaf tissue by the plant-pathogenic fungus Botrytis cinerea and the saprophytic fungal antagonist Ulocladium atrum was constructed. Both fungi explore the leaf and utilize the resources it provides. Leaf tissue is represented by a two-dimensional grid of square grid cells. Fungal competition within grid cells is modeled using Lotka-Volterra equations. Spatial expansion into neighboring grid cells is assumed proportional to the mycelial density gradient between donor and receptor cell. Established fungal biomass is immobile. Radial growth rates of B. cinerea and U. atrum in dead cyclamen leaf tissue were measured to determine parameters describing the spatial dynamics of the fungi. At temperatures from 5 to 25°C, B. cinerea colonies expanded twice as rapidly as U. atrum colonies. In practical biological control, the slower colonization of space by U. atrum thus needs to be compensated by a sufficiently dense and even distribution of conidia on the leaf. Simulation results confirm the importance of spatial expansion to the outcome of the competitive interaction between B. cinerea and U. atrum at leaf scale. A sensitivity analysis further emphasized the importance of a uniform high density cover of vital U. atrum conidia on target leaves.

To ensure the productivity of smallholder maize production systems in Central America, increased attention must be paid to conserving soil and water resources. Various stakeholders from national agricultural research services (NARS), networks, non-governmental organizations (NGO's) and research institutes seek to develop and target productivity enhancing resource conserving management practices such as crop residue retention systems. To support this process, a methodology with explicit spatial and temporal dimensions using the DSSAT crop simulation models was developed and applied to the case study of residue retention in maize production systems of Jalisco, Mexico. Systems where crop residues were partially or totally retained were compared with systems with no residue retention. Variables considered included crop production, soil surface runoff water, soil organic carbon and soil organic nitrogen content. Gridded climate surfaces and a range of soil profile scenarios formed the basis of the regional input. Three levels of nitrogen application (0, 150 and 235 kg ha(-1)) were selected to represent current agronomic practices. Simulation models for maize and fallow were run in sequence for 12 consecutive years. Results demonstrated that soil water holding capacity and topography affected benefits of residue retention much more than nitrogen management. Benefits to maize production from residue retention were found mainly in areas in the northeast of Jalisco and surrounding regions, where low precipitation limits maize production. Reductions in soil surface runoff due to residue retention were most evident in high rainfall areas in the central-east of Jalisco and surrounding regions. Although the effect of soil loss is not accounted for in DSSAT, areas of pronounced soil surface runoff reduction are hypothesized to be areas of productivity gain in the longer term. The assessment provided insight in the regional potential for and the soil and climate conditions under which successful introduction of residue retention in maize cropping systems in Jalisco may be achieved. In combination with socio-economic assessment studies and experimental work, the approach and its results contribute to targeted introduction of new production technologies. (C) 2004 Published by Elsevier Ltd.

Nucleotide-sugar transporters (NSTs) form a family of structurally related transmembrane proteins that transport nucleotide-sugars from the cytoplasm to the endoplasmic reticulum and Golgi lumen. In these organelles, activated sugars are substrates for various glycosyltransferases involved in oligo- and polysaccharide biosynthesis. The Arabidopsis thaliana genome contains more than 40 members of this transporter gene family, of which only a few are functionally characterized. In this study, two Arabidopsis UDP-galactose transporter cDNAs (UDP-GalT1 and UDP-GalT2) are isolated by expression cloning using a Chinese hamster ovary cell line (CHO-Lec8) deficient in UDP-galactose transport. The isolated genes show only 21% identity to each other and very limited sequence identity with human and yeast UDP-galactose transporters and other NSTs. Despite this low overall identity, the two proteins clearly belong to the same gene family. Besides complementing Lec8 cells, the two NSTs are shown to transport exclusively UDP-galactose by an in vitro NST assay. The most homologous proteins with known function are plant transporters that locate in the inner chloroplast membrane and transport triose-phosphate, phosphoenolpyruvate, glucose-6-phosphate, and xylulose 5-phosphate. Also, the latter proteins are members of the same family, which therefore has been named the NST/triose-phosphate transporter family.

Soil-loss, food insecurity, population pressure and low income of the rural population are interrelated problems in the Loess Plateau of northern China, and result in a spiral of unsustainability. This paper examines Ansai County as a case study to explore strategic land use options that may meet well-defined goals of regional development, using a systems approach that integrated the fragmented and empirical information on the biophysical, agronomic and socio-economic conditions. We used production ecological principles, simulation modeling and multiple goal linear programming as integrative tools. Four scenarios were explored, representing major directions of agricultural development in the region and views of national and local stakeholders, farmers and environmentalists. The results indicate that soil conservation, food self-sufficiency and income for the rural population can be substantially improved by efficient resource use and appropriate inputs. In the long-term, terracing and use of crop rotations with alfalfa may be the best options for soil conservation. The large rural population and the lack of off-farm employment opportunities could be the most important factors affecting rural development in Ansai. This study contributes to the understanding of regional problems and agricultural development potentials, and shows' agro-technical possibilities for alleviating the unsustainability problems in this fragile and poorly endowed region. To promote actual development towards the identified options, on-farm innovation and appropriate policy measures are needed. The explored land use options enable a much more targeted innovation and development of policies. (C) 2003 Elsevier Ltd. All rights reserved.

Severe soil erosion and food security problems are the most important issues in the Loess Plateau of northern China, which are closely related to the over-cultivation and poor management of marginal land resources. Alleviation of these unsustainability problems requires, among many other things, alternative and innovative cropping systems. This paper describes the identification of such cropping systems and their quantitative evaluation. It uses an operationalized approach based on production ecological concepts, and the application of the simulation model EPIC for the case of Ansai County in the Loess Plateau. Based on four criteria, i.e. suitable land units, crop rotations, production situations, and agro-techniques for water and soil conservation, we identified 548 cropping systems. The yield potentials and efficiencies in terms of soil and nutrient conservation were quantitatively evaluated for each of the cropping systems. The results indicated that the low productivity, and serious soil and water losses in current cropping systems may be greatly alleviated by increasing nutrient inputs and use of soil conservation measures, such as growing crops in rotations with alfalfa, using crop residues as mulch, and furrow-ridging tillage. For most crops, the current yield may be at least doubled by good soil and crop management with appropriate inputs. The study suggests a range of crop rotations that satisfy food production, soil and water conservation and economic objectives to different extent. The results of this study can serve two purposes. First, they may help setting an agenda for empirical and experimental research aimed at the testing and improving of cropping systems, and second, the cropping systems can be input for an integrated land use study that weighs objectives at regional scale and reveals potential and strategic land use options. (C) 2002 Elsevier Science B.V. All rights reserved.

The objective of this study was to identify to what extent rice productivity problems are caused by soil quality problems (soil alkalinity) and to what extent by sub-optimal crop management. The study area used is the Foum Gleita irrigation scheme, MauritaniaFarmers in the Foum Gleita irrigation scheme in southern central Mauritania experienced declining rice yields, and within a decade after its establishment 12% of the scheme's land had been abandoned. Actual rice yields (less than or equal to 4.0 t ha(-1)) are low in comparison with potential yield (ca. 8 t ha(-1)) and with yields elsewhere in the Sahel (4-6 t ha(-1)). Farmers related the productivity problems to salt efflorescences on the soil surface. Rice yields on the 'upper and middle slope' soils were lower (3.4 t ha(-1)) than the yields on soils further down the slope (> 4.2 t ha(-1)). Farmers classified the 'upper and middle slope' soils as degraded, but following the USDA classification the soils could not be classified saline or sodic. Low yields on the 'degraded' soils were related to co-limitation of nitrogen (N) and phosphorus (P), which was due to low soil N supply (ca. 18 kg ha(-1)), low soil P supply (ca. 8 kg ha(-1)), occasional low N fertilizer doses (35 kg N ha(-1)) in combination with low N fertilizer recovery efficiency (0.3 kg kg(-1)), or non-application of P fertilizer. On the 'non-degraded' soils, soil P supply (ca. 16 kg ha(-1)) was higher and N deficiency prevailed despite a higher soil N supply (ca. 32 kg ha(-1)) and a higher N fertilizer recovery efficiency (0.4 kg kg(-1)). Higher contents of carbonate salts in the 'degraded' soils increase soil pH (> 7.5) and are, therefore, likely to contribute to low soil P supply and low N fertilizer recovery efficiency.

De achtergronden van de achterblijvende productiviteit van de landbouw in Afrika worden geschetst, waarna oplossingsrichtingen tot verbetering worden aangegeven

Recent classical swine fever (CSF) epidemics in the European Union (EU) have clearly shown that preventing the introduction of CSF virus (CSFV) deserves high priority. Insight into all the factors contributing to the risk of CSFV introduction is a prerequisite for deciding which preventive actions are cost-effective. The relations between virus introduction and spread, prevention and control, and economic losses have been described using the conceptual framework presented in this paper. A pathway diagram provides insight into all the pathways contributing to the likelihood of CSFV introduction (LVI_CSF) into regions of the EU. A qualitative assessment based on this pathway diagram shows that regions with high pig densities generally have a higher LVI_CSF, although this cannot be attributed to pig density only. The pathway diagram was also used to qualitatively assess the reduction in LVI_CSF achieved by restructuring the pig production sector. Especially integrated chains of industrialised pig farming reduce the LVI_CSF considerably, but are also difficult and costly to implement. Quantitative assessment of the LVI_CSF on the basis of the pathway diagram is needed to support the results of the qualitative assessments described.

We have developed a novel strategy for the introduction of durable insect resistance in crops. This strategy was based on intervention in the natural relationship between plants and insects. For many insects, including pests such as thrips (Frankliniella occidentalis), the flower is an important factor in their life cycle, serving either as a food source or as a place for mating. The insects are attracted to the flower by scent, which is mainly produced by the petals, and by the bright colour of these floral organs. We therefore anticipated that removal or changing the identity of the petals would significantly reduce the attractiveness of the flower to thrips. To test this hypothesis, we used cucumber as a model species because most modern varieties are parthenocarpic, in which the fruit develops without fertilization. The cucumber mutant green petals, in which the petals are homeotically transformed into green sepals, was particularly useful for this study. The susceptibility of the cucumber plants to damage by thrips was determined by recording thrip numbers and by measuring leaf damage. Large differences were observed when greenhouse compartments with either wild-type or green petal mutant plants were compared. The rate of population growth of the insects on the mutant plants was significantly reduced and the leaves were almost undamaged. These results demonstrate that alterations in the structure of flowers may interfere with the life cycle of insects, providing the means for a novel and natural strategy for obtaining insect resistance.

This paper addresses water uptake by roots as calculated in summary crop growth models for use at the land use systems level. Simple comparative exercises were carried out using three models. The results show considerable differences in daily and cumulative water uptake. One model calculates moisture changes for subdivisions of the root zone, even though the procedure on which it is based was intended for use over the rooted zone as a whole. This is combined with an algorithm to allow for compensatory effects in soils with non-uniform water distribution, resulting in artefacts. The results of another model based on the electrical analogue, confirm that theoretical models help to improve understanding of complex processes and guide research, but using them for predictions may give worse results than conventional empirical methods. The third model uses a ‘soil water depletion fraction’ to indicate the limit of readily available water in the rooted soil as a whole. The procedure was originally developed for irrigated agriculture and seems inappropriate for rain fed conditions characterised by irregular wetting and drying cycles that result in non-uniform soil water distribution. Simple comparative exercises as carried out, help to reveal weak points in the models studied and indicate ranges of uncertainty. Error propagation analyses using local data must be added to indicate whether improvements at local level are necessary and to identify priorities for further research, feeding an upward spiral to enhance model accuracy.

The incidence of asymptomatic travel-related parasitic infection is uncertain. Previous studies did not distinguish new incident infections, from past infections. Regardless of symptoms, we performed multiplex real-time polymerase chain reaction on pre- and post-travel stool samples of Dutch long-term travelers to the (sub)tropics. Serological screening for Schistosoma spp. was only performed in travelers to sub-Saharan Africa. In total, 679 travelers were included in the study. The follow-up rate was 82% (556 of 679). Participants' median travel duration was 12 weeks. There was one incident infection with Strongyloides stercoralis; there were none with Entamoeba histolytica, 4 with Cryptosporidium spp. (1%), and 22 with Giardia lamblia (4%). Nine of 146 travelers (6%) seroconverted for Schistosoma spp. Routine screening of stool samples for parasitic infection is not indicated for asymptomatic people, who travel to the (sub)tropics for up to 3 months. Screening for Schistosoma spp. should be offered to travelers with fresh-water contact in endemic regions.

The fact is simple: 842 million people are currently hungry. These people are some of about 2 billion who lack, at least at times, essential nutrients even if they consume enough calories. A century ago, more than half of humankind was severely malnourished in terms of calories and proteins; today this number is only 1 in 8 - much lower than in the past, but still unacceptably high. In the last two decades, more people than ever before - 1 billion - have been lifted out of poverty and hunger. About 75% of this spectacular global reduction occurred in China. Making similar progress in the next decades means tackling Africa and India.

In een academische wereld die steeds competitiever wordt, willen we graag weten wat ‘de beste’ universiteit is. Verschillende rankings bedienen ons op onze wenken, waaronder Times Higher Education, Sjanghai, QS en Leiden. De kritiek op die lijsten is echter niet mals, ook omdat universiteiten graag selectief shoppen in de resultaten. Toch kunnen we niet om ze heen, meent informatiespecialist Wouter Gerritsma.

Met behoud van productiekracht speelt de Nederlandse landbouw in op maatschappelijke wensen. Volgens bestuursvoorzitter Louise Fresco van Wageningen UR, geeft dat een belangrijke voorsprong.

During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006-2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases.

Aalt Dijkhuizen baarde in 2012 veel opzien toen hij luid hoorbaar verkondigde dat de agrarische producties omhoog moeten vanwege de wereldwijde voedselbehoefte. Vanuit agrarische kringen ging applaus op, dierenwelzijnsorganisaties hadden felle kritiek. Beide reacties kan Dijkhuizen zich voorstellen. Alleen het onfatsoen waarmee sommige NGO’s en hun sympathisanten reageerden, vindt hij ongehoord. Op 1 maart 2014 stopt Dijkhuizen als voorzitter van de raad van bestuur van Wageningen UR. In dit interview blikt hij terug op twaalf jaar voorzitterschap.

Grote delen van de wereld kampen met een structureel gebrek aan voedsel. Tegelijkertijd is nog steeds in veel landbouwsystemen sprake van intensief gebruik van gewasbeschermingsmiddelen. Op beide fronten is enorme winst te boeken door radicaal te kiezen voor een ecologische benadering. Onder de noemer Best Ecological Means is deze ontwikkeling de laatste jaren in een stroomversnelling geraakt.