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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Using yield gap analysis to give sustainable intensification local meaning
Silva, João Vasco - \ 2017
University. Promotor(en): Martin van Ittersum, co-promotor(en): Ken Giller; Pytrik Reidsma. - Wageningen : Wageningen University - ISBN 9789463437141 - 361
crops - yields - crop yield - modeling - simulation models - cereals - farming systems - yield losses - gewassen - opbrengsten - gewasopbrengst - modelleren - simulatiemodellen - graansoorten - bedrijfssystemen - oogstverliezen

Yield gap analysis is useful to understand the relative contribution of growth-defining, -limiting and -reducing factors to actual yields. This is traditionally performed at the field level using mechanistic crop growth simulation models, and directly up-scaled to the regional and global levels without considering a range of factors intersecting at farm and farming system levels. As an example, these may include farmers' objectives and resource constraints, farm(er) characteristics, rotational effects between subsequent crops or decisions on resource allocation and prioritization of crop management. The objective of this thesis is to gain insights into yield gaps from a farm(ing) systems perspective in order to identify opportunities for sustainable intensification at local level.

Three contrasting case studies representing a gradient of intensification and capturing a diversity of agricultural systems were selected for this purpose, namely mixed crop-livestock systems in Southern Ethiopia, rice based-farming systems in Central Luzon (Philippines) and arable farming systems in the Netherlands. A theoretical framework combining concepts of production ecology and methods of frontier analysis was developed to decompose yield gaps into efficiency, resource and technology yield gaps. This framework was applied and tested for the major crops in each case study using crop-specific input-output data for a large number of individual farms. In addition, different statistical methods and data analyses techniques were used in each case study to understand the contribution of farmers' objectives, farm(er) characteristics, cropping frequency and resource constraints to yield gaps and management practices at crop level.

Yield gaps were largest for maize and wheat in Southern Ethiopia (ca. 80\\\\% of the water-limited yield), intermediate for rice in Central Luzon (ca. 50\\\\% of the climatic potential yield) and smallest for the major arable crops in the Netherlands (ca. 30\\\\% of the climatic potential yield). The underlying causes of these yield gaps also differed per case study. The technology yield gap explained most of the yield gap observed in Southern Ethiopia, which points to a lack of adoption of technologies able to reach the water-limited yield. The efficiency yield gap was most important for different arable crops in the Netherlands, which suggests a sub-optimal timing, space and form of the inputs applied. The three intermediate yield gaps contributed similarly to the rice yield gap in Central Luzon meaning that sub-optimal quantities of inputs used are as important in this case study as the causes mentioned for the other case studies.

Narrowing the yield gap of the major crops does not seem to entail trade-offs with gross margin per unit land in each case study. However, the opposite seems to be true for N use efficiency and labour productivity particularly in Southern Ethiopia and Central Luzon, and to a less extent in the Netherlands. This means that (sustainable) intensification of smallholder agriculture in the tropics needs to go hand-in-hand with agronomic interventions that increase land productivity while ensuring high resource use efficiency and with labour-saving technologies that can reduce the drudgery of farming without compromising crop yields.

Other insights at farm(ing) system level were clearer in Southern Ethiopia than in Central Luzon or in the Netherlands. For example, alleviating capital constraints was positively associated with intensification of maize-based farming systems around Hawassa and increases in oxen ownership (an indicator of farm power) was associated with extensification of wheat-based farming systems around Asella. In Central Luzon, farm and regional factors did not lead to different levels of intensification within the variation of rice farms investigated and the most striking effect was that direct-seeding (and thus slightly lower rice yields) was mostly adopted in larger farms, and used lower amounts of hired labour, compared to transplanting. In the Netherlands, the analysis of rotational effects on crop yields provided inconclusive results but confounding effects with e.g. rented land do not allow to conclude that these are not at stake in this farming system.

This thesis broadens the discussion on yield gaps by moving from the technical aspects underlying their estimation towards the broader farm level opportunities and constraints undermining their closure. Overall, insights from contrasting case studies support conventional wisdom that intensification of agriculture needs to occur in the 'developing South', where yield gaps are large and resource use efficiency low, while a focus on improving sustainability based on sustainable intensification (or even extensification) is more appropriate in the 'developed North', where yield gaps are small and resource use efficiency high.

Physiological responses of rice to increased day and night temperatures
Shi, Wanju - \ 2017
University. Promotor(en): Paul Struik, co-promotor(en): Xinyou Yin. - Wageningen : Wageningen University - ISBN 9789463437110 - 202
crops - rice - oryza sativa - plant physiology - temperature - crop yield - grain - agronomy - gewassen - rijst - plantenfysiologie - temperatuur - gewasopbrengst - graan - agronomie

A more rapid increase in night-time temperature compared with day-time temperature and the increased frequency of heat waves associated with climate change present a serious threat to rice (Oryza sativa L.) production and food security. This thesis aims to understand the impact of high night-time temperature (HNT) and high day-time temperature (HDT) on rice grain yield and grain quality and to examine adaptation strategies to cope with high-temperature stresses.

Grain yield and quality of a susceptible indica genotype (Gharib) and all tested hybrids, when exposed to HNT in the field, were significantly reduced across seasons, with less average reduction in the dry season than in the wet season, indicating that other environmental factors under field conditions may contribute to impacts of HNT on yield. Among the different yield components, a reduced number of spikelets m−2 significantly contributed to yield loss under HNT followed by the consistently lower single-grain weight across all genotypes, while the impact of the decrease in percentage seed-set was less and season-specific. Lower grain yield and poorer grain quality in susceptible cultivar Gharib were associated with a significant reduction in non-structural carbohydrate translocation after flowering, resulting in reduced grain-filling duration. Increased total nitrogen application did not alleviate the negative impact of HNT. The proposed model approach showed that there were significant differences among cultivars in their changes in source-sink relationships in response to HNT. Given that rice grain yield and quality are challenged by a rise in HDT and HNT, in particular at flowering and during grain filling, differential impacts of HNT and HDT during these critical stages were observed. For the single-grain growth during grain filling, HDT either independently or in combination with HNT exerted greater influences than HNT on the grain filling dynamics, activities of starch metabolism enzymes, temporal starch accumulation patterns, and the process of chalk formation. During flowering, HDT increased spikelet sterility in tested hybrids and hybrids were less tolerant to high temperatures than high-yielding inbred varieties. Moreover, in contrast with HNT, HDT played a dominant role in determining spikelet fertility. Novel observations with a series of snapshots of dynamic fertilization processes demonstrated that disturbances in the pre-fertilization phase were the primary causes for heat-induced spikelet sterility, indicating the effectiveness of employing the early-morning flowering trait for mitigating the impact of heat stress at flowering on rice.

Modelling of genotype by environment interaction and prediction of complex traits across multiple environments as a synthesis of crop growth modelling, genetics and statistics
Bustos-Korts, Daniela - \ 2017
University. Promotor(en): Fred van Eeuwijk, co-promotor(en): Marcos Malosetti Zunin. - Wageningen : Wageningen University - ISBN 9789463436694 - 340
crops - applied statistics - genotype environment interaction - complex loci - quantitative genetics - gewassen - toegepaste statistiek - genotype-milieu interactie - complexe loci - kwantitatieve genetica

The main objective of plant breeders is to create and identify genotypes that are well-adapted to the target population of environments (TPE). The TPE corresponds to the future growing conditions in which the varieties produced by a breeding program will be grown. All possible genotypes that could be considered as selection candidates for a specific TPE are said to belong to the target population of genotypes, TPG. Genotypes commonly show different sensitivities to environmental gradients and then genotype by environment interaction (GxE) is observed. GxE can lead to changes in genotypic ranking, complicating the breeding process. The main aim of this thesis was to investigate statistical models and the combination of statistical and crop growth models to improve phenotype prediction across multiple environments. One aspect that determines the quality of phenotype prediction is the set of genotypes used to train the prediction model, especially when the TPG is structured. We proposed a method that uniformly covers the genetic space of the TPG, leading to a larger prediction accuracy than random sampling. We produced positive results for wheat, maize and rice. A second aspect that influences the accuracy of phenotype predictions is the choice of environments used to train the prediction model, which should capture the heterogeneity in the TPE. When accounting for heterogeneity in environmental quality, it is important to distinguish between repeatable and well predictable elements in the environmental conditions from those that are badly predictable. We proposed statistical methods based on the AMMI model and on mixed models to identify groups of environments that show repeatable GxE, illustrating our ideas with multi-environment wheat data in North-Western Europe. The importance of training set construction strategies and multi-environment genomic prediction models was also demonstrated for barley data. If breeders are interested in identifying the genetic basis of the target traits, it is advantageous to have a higher SNP density. In this thesis, we used exome sequence data of the EU-Whealbi-barley germplasm, which corresponds to a unique set of genotypes with a diverse origin, growth habit and breeding history. For this diverse data, we assessed the effects of QTLs and haplotypes across multiple environments for awn length, grain weight, heading date and plant height. Our results show that the EU-Whealbi-barley collection possesses a large diversity of promising alleles regulating the four traits we analysed. The last major topic addressed in this thesis is the use of a combination of statistical-genetic models and crop growth models (APSIM) as a strategy to assess the traits and phenotyping schemes to improve the prediction accuracy of a target trait like yield. We assess the potential of the combined modelling approach to characterize a sample of the TPG and TPE, and illustrate how trait correlations are modified by environmental conditions and by the genetic architecture of the sample of the TPE. We discuss the topics mentioned above, from a didactical perspective, proposing a list of subjects that should be covered in a GxE course for plant breeders. Finally, we discuss challenges and opportunities presented by the characterization of the TPE and TPG when using simulations based on statistical and crop growth models.

UAV-based multi-angular measurements for improved crop parameter retrieval
Roosjen, Peter P.J. - \ 2017
University. Promotor(en): Martin Herold, co-promotor(en): Jan Clevers; Harm Bartholomeus. - Wageningen : Wageningen University - ISBN 9789463436717 - 133
reflectance - anisotropy - crops - soil water content - drones - remote sensing - reflectiefactor - anisotropie - gewassen - bodemwatergehalte

Optical remote sensing enables the estimation of crop parameters based on reflected light through empirical-statistical methods or inversion of radiative transfer models. Natural surfaces, however, reflect light anisotropically, which means that the intensity of reflected light depends on the viewing and illumination geometry. Therefore, reflectance anisotropy can be considered as an unwanted effect since it may lead to inaccuracies in parameter estimations. However, it can also be considered as information source due to its unique response to the optical and structural properties of the observed surface. In the past, reflectance anisotropy was studied by multi-angular reflectance measurements from space-borne or ground-based sensors. In this research, the opportunities of Unmanned Aerial Vehicles (UAVs) to collect multi-angular measurements were explored. The main results of this research show that multi-angular measurements can be done with UAVs and that the reflectance anisotropy signal can be used to improve the retrieval of crop parameters.

Coexistence of GMO production, labeling policies, and strategic firm interaction
Venus, Thomas Johann - \ 2017
University. Promotor(en): Justus Wesseler, co-promotor(en): Dusan Drabik; M.J. Punt. - Wageningen : Wageningen University - ISBN 9789463436670 - 148
genetically engineered organisms - food products - nutrition labeling - labelling - crops - plant breeding - germany - european union - regulations - markets - businesses - genetisch gemanipuleerde organismen - voedselproducten - etiketteren van voedingsmiddelen - etiketteren - gewassen - plantenveredeling - duitsland - europese unie - regelingen - markten - bedrijven

This dissertation analyzes the market effects of the coexistence of genetically modified organism (GMO) and conventional production, labeling policies, and strategic firm interactions through vertical product differentiation. Although we focus on GMOs, the applied frameworks can be adopted and extended to other differentiated products where similar concepts apply.

The main body of the dissertation consists of four chapters. In the first chapter, we estimate the perceived costs of legal requirements (‘coexistence measures’) for growing genetically modified (GM) Bt maize in Germany using a choice experiment. The costs of the evaluated ex-ante and ex-post coexistence measures range from zero to more than 300 euros per hectare per measure, and most of them are greater than the extra revenue the farmers in our survey expect from growing Bt maize or than the estimates in the literature. The cost estimates for temporal separation, which were the highest in our evaluation, imply that the exclusion of this measure in Germany is justified. The costliest measures that are currently applied in Germany are joint and strict liability for all damages. Our results further show that neighbors do not cause a problem and that opportunities for reducing costs through agreements with them exist. Finally, we find that farmers’ attitudes toward genetically modified crops affect the probability of adoption of Bt maize. Our results imply that strict liability will deter the cultivation of Bt maize in Germany unless liability issues can be addressed through other means, for example, through neighbor agreements.

The coexistence costs have implications for the supply of products in which GMOs are excluded from the production process (i.e., non-GM labeling). This is the topic of the second chapter. In that chapter, we discuss and illustrate the complexity of non-GM food labeling in Germany. We show how a multi-stakeholder organization that sets a voluntary private production and certification standard can combine the opposing and agreeing interests of its members. This cohesion reduces the fears of retailers of NGO pressure in the case of mislabeling. Whereas non-GM labeling in Germany started as a niche for farmer-to-consumer direct marketing and small processors, it was further driven by anti-GMO organizations. Today, retail chains label some of their store brands and are now the drivers. We also discuss how informing consumers through non-GM labeling addresses imperfect information, but at the same time, can create new information imperfections if consumers are not well informed about the labeling system itself.

Non-GM labeling, together with the EU-wide mandatory labeling of GMOs and their requirements on coexistence, have implications for the potential regulation of crops derived by new plant breeding techniques (NPBTs). In the third chapter, we analyze the market and welfare effects of regulating crops derived by NPBTs as genetically modified or conventional products. We consider the mandatory scheme for labeling GM products and a voluntary non-GM scheme for labeling livestock products derived from non-GM feed. We develop a partial equilibrium model that explicitly takes into account both the coexistence costs at the farm level and the segregation and identity preservation costs at the downstream level. By applying the model to EU rapeseed, we find that regulating NPBTs as GM (as compared to non-GM) in combination with mandatory and voluntary labeling increases prices and therefore makes producers better off. We also show that higher coexistence costs make the price increasing effect even stronger. Voluntary non-GM labeling applied to feed makes consumers in this sector overall worse off, but it benefits farmers and rapeseed oil consumers overall as long as segregation costs are low. Consumers of biodiesel and industrial products, such as lubricants produced from GM rapeseed, benefit from high segregation costs. We show that the effects of farm-level coexistence costs largely differ from the effects of downstream market segregation costs.

In the last of the four chapters, we consider the effects of market power and analyze the decision of investing in quality updating when high-quality product demand is growing. We model a decision of a duopoly that initially offers a product perceived as lower quality (e.g., GM product) to invest in an emerging high-quality (e.g., labeled non-GM) product. We investigate whether the smaller or the larger firm invests first. Either preemption or a war of attrition can result, depending on demand and cost factors. For each case, we derive the unique Nash equilibrium. We show that a firm’s timing to invest in high-quality production (e.g., implement a voluntary production standard) depends on several factors, such as the difference in firm size between competing firms and the level of vertical differentiation, growth and discount rate, demand parameters, and per-unit production costs. We show that institutions, which set private or public certification standards, can affect firms’ investment in differentiated products because the standard stringency affects the production and compliance costs as well as the level of product differentiation. Hence, through the setting of these standards, private and governmental institutions can impact the market structure as well as the growth of an emerging market. Finally, we discuss policy implications and how an adjustment of the EU-regulatory framework from a process- to a product-based system can make several issues discussed in this thesis problems of the past.

Crop growth and development in closed and semi-closed greenhouses
Qian, Tian - \ 2017
University. Promotor(en): Leo Marcelis, co-promotor(en): Anja Dieleman; Anne Elings. - Wageningen : Wageningen University - ISBN 9789463430708 - 112
crops - crop production - growth - greenhouse crops - greenhouse horticulture - climate - semi-closed greenhouses - photosynthesis - temperature - gewassen - gewasproductie - groei - kasgewassen - glastuinbouw - klimaat - semi-gesloten kassen - fotosynthese - temperatuur

(Semi-)closed greenhouses have been developed over the last decades to conserve energy. In a closed greenhouse, window ventilation is fully replaced by mechanical cooling while solar heat is temporarily stored in an aquifer. A semi-closed greenhouse has a smaller cooling capacity than a closed greenhouse and, in which mechanical cooling is combined with window ventilation. (Semi-)closed greenhouses create new climate conditions: high CO2 concentrations irrespective of the outdoor climate, and vertical gradients in temperature and vapour pressure deficit throughout the canopy. This thesis focuses on the crop physiology in (semi-)closed greenhouses, and investigates the effects of the new climate conditions on crop growth, development and underlying processes.

Cumulative production in (semi) closed greenhouses increased by 6-14% compared to the open greenhouse, depending on the cooling capacity. The production increase in the (semi-)closed greenhouses was explained by the higher CO2 concentrations. In many species, feedback inhibition of photosynthesis occurs when plants are grown at high CO2. The results, however, suggest that high CO2 concentrations do not cause feedback inhibition in high producing crops, because the plants have sufficient sink organs (fruits) to utilise all assimilates. Pruning experiments showed that photosynthetic acclimation to elevated CO2 concentration only occurred when the number of fruits was considerably reduced.

Cooling below the canopy induced vertical temperature and vapour pressure deficit gradients. These gradients correlated with outside radiation and outside temperature. Despite the occurrence of vertical temperature gradients, plant growth and fruit yield were mostly unaffected. Leaf and truss initiation rates did not differ in the presence or absence of a vertical temperature gradients, since air temperatures at the top of the canopy were kept comparable. The only observed response of plants to the vertical temperature gradient was the reduced rate of fruit development in the lower part of the canopy. This resulted in a longer period between anthesis and fruit harvest and an increase in the average fruit weight in summer. However, total fruit production over the whole season was not affected.

The effects of the climate factors light, CO2 concentration, temperature, and humidity on leaf photosynthesis were investigated. The photosynthesis model of Farquhar, von Caemmerer and Berry (FvCB) was modified by adding a sub-model for Ribulose-1,5-bisphosphate carboxylase (Rubisco) activation. The photosynthetic parameters: the maximum carboxylation capacity (Vcmax) and the maximum electron transport rate (Jmax), α (the efficiency of light energy conversion), θ (the curvature of light response of electron transport), and Rd (the non-photorespiratory CO2 release) were estimated based on measurements under a wide range of environmental conditions in the semi-closed greenhouse. The simultaneous estimation method and the nonlinear mixed effects model were applied to ensure the accuracy of the parameter estimation. Observations and predictions matched well (R2=0.94).

The yield increase in a closed greenhouse, compared to that in an open greenhouse was analyzed based on physiological and developmental processes. The yield increase in the (semi-)closed greenhouses was the result of an increase of net leaf photosynthesis. The (semi-)closed greenhouses have been applied commercially first in the Netherlands, and later in other countries. The knowledge obtained from (semi-)closed greenhouses is applied in conventional open greenhouse as well, which is called the next generation greenhouse cultivation. A number of innovations are being developed for greenhouse industry to reduce energy consumption while improving production and quality.

Cadmium in soil, crops and resultant dietary exposure
Rietra, R.P.J.J. ; Mol, G. ; Rietjens, I.M.C.M. ; Römkens, P.F.A.M. - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2784) - 39
cadmium - soil - food intake - crops - exposure - fertilizers - food safety - toxicology - bodem - voedselopname - gewassen - blootstelling - kunstmeststoffen - voedselveiligheid - toxicologie
Grasklaverteelt motor voor samenwerking en klimaatadaptatie : 'climatecafe' evalueert samenwerking akkerbouw- en veeteeltbedrijven
Wit, Jan de; Adelhart Toorop, R.L. de - \ 2016
Ekoland (2016)12. - ISSN 0926-9142 - p. 20 - 21.
klimaatadaptatie - klimaatverandering - samenwerking - grasklaver - teelt - biologische landbouw - gewassen - gewasbescherming - akkerbouw - veehouderij - climate adaptation - climatic change - cooperation - grass-clover swards - cultivation - organic farming - crops - plant protection - arable farming - livestock farming
Het wordt natter en warmer in Nederland voorspelt het KNMI. Is de biologische boer bezig met deze verandering? Dat valt wel mee. Er wordt gewerkt aan een goede bodemkwaliteit en structuur. Dat draagt bij aan het aanpassingsvermogen aan een veranderend klimaat (‘adaptatie’). Grasklaver als rustgewas helpt de akkerbouwer daarbij, zo blijkt ook uit modelberekeningen.
Transition to more water efficient agriculture production in Thailand : Fact finding
Blom-Zandstra, M. ; Kempenaar, C. ; Rothuis, A.J. - \ 2016
Wageningen : Wageningen Plant Research (Report / Wageningen Plant Research 663) - 22 p.
crops - water use efficiency - water deficit - crop production - thailand - gewassen - watergebruiksrendement - watertekort - gewasproductie
Thailand will face major water scarcity problems. The question is how Thailand can remain an important producer of agriculture crops (such as rice) while facing severe water shortages in the near future. To generate “more crop per drop” a sequence of innovations need to be introduced.
Simulation nitrogen-limited crop growth with SWAP/WOFOST : process descriptions and user manual
Groenendijk, Piet ; Boogaard, Hendrik ; Heinen, Marius ; Kroes, J.G. ; Supit, Iwan ; Wit, Allard de - \ 2016
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2721) - 59
crops - growth - soil - nitrogen - organic matter - mineralization - leaching - simulation models - nitrates - gewassen - groei - bodem - stikstof - organische stof - mineralisatie - uitspoelen - simulatiemodellen - nitraten
This report describes a soil nitrogen module (Soil-N), which is combined with the agro-hydrological model, SWAP, and the crop growth model, WOFOST. The core of the Soil-N module is a description of the nitrogen cycle, which is coupled to the organic matter cycle based upon the RothC-26.3 model. Nitrogen can be supplied to the soil as different types of fertilizer applications and through mineralisation of organic nitrogen. Ammonium and nitrate balances are calculated including uptake by plant roots, de-nitrification and leaching of nitrate. Data exchange is on a daily base. The partitioning of nitrogen within crops and the nitrogen contents of crop residues are calculated by WOFOST and passed to the Soil-N module. SWAP generates the data for establishing the water balance of the soil compartment for which the Soil-N perform the simulations. Nitrogen uptake by the crop is calculated as the minimum of the demand by the crop and the availability of nitrogen in the soil. The crop production rate is reduced when the mineral nitrogen stock is limited. Nitrogen-fixation is based on a simple approach. An improved sub-model for phenological stages of soybean was implemented. Increasing atmospheric CO2 concentrations can be accounted for. The innovated integrated model was tested using data sets from The Netherlands, China and Argentina, for which examples are given. This new model can be used as a tool in studies, in which both water and nitrogen can be limited for crop growth.
Inventarisatie en analyse zouttolerantie van landbouwgewassen op basis van bestaande gegevens
Stuyt, L.C.P.M. ; Blom-Zandstra, M. ; Kselik, R.A.L. - \ 2016
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2739) - 157
veldgewassen - gewassen - zouttolerantie - verzilting - zoet water - waterbeheer - watervoorziening - field crops - crops - salt tolerance - salinization - fresh water - water management - water supply
In het Deltaprogramma Zoetwater is het lastig gebleken economische analyses te maken voor de programmering van maatregelen en/of de beleidsmatige afweging rond waterbeschikbaarheid. Een van de knelpunten is het gemis aan inzicht in de droogte- en zoutschade in landbouw en natuur. De zoutschade aan landbouwgewassen is nog niet goed in beeld; er zijn veel getallen in omloop, maar de manier waarop deze tot stand zijn gekomen en/of gerapporteerd is niet eenduidig. Daarom is de tussen 1950 en 2015 in Nederland beschikbaar gekomen informatie geanalyseerd. Het resultaat is specificatie van zouttolerantiedrempels voor 35 gewassen en gewasgroepen, gekoppeld aan het zoutgehalte van beregeningswater.
Methodology for estimating emissions from agriculture in the Netherlands. : Calculations of CH4, NH3, N2O, NOx, PM10, PM2.5 and CO2 with the National Emission Model for Agriculture (NEMA)
Vonk, J. ; Bannink, A. ; Bruggen, C. van; Groenestein, C.M. ; Huijsmans, J.F.M. ; Kolk, J.W.H. van der; Luesink, H.H. ; Oude Voshaar, S.V. ; Sluis, S.M. ; Velthof, G.L. - \ 2016
Wageningen : Statutory Research Tasks Unit for Nature & the Environment (WOt-technical report 53) - 164 p.
air pollutants, greenhouse gases, livestock, crops, animal housing, manure storage, manure application, inorganic fertilizer, enteric fermentation, manure management, agricultural soils, liming, NIR, CRF, IIR, NFR - landbouw - gewassen - landbouwgronden - vee - huisvesting, dieren - dierlijke meststoffen - rundveemest - mestverwerking - begrazing - broeikasgassen - luchtverontreinigende stoffen - emissie - ammoniakemissie - kooldioxide - methaan - anorganische meststoffen - fermentatie - bekalking - nederland - compost - rioolslib - teelt - oogstresten - rijp worden - agriculture - crops - agricultural soils - livestock - animal housing - animal manures - cattle manure - manure treatment - grazing - greenhouse gases - air pollutants - emission - ammonia emission - carbon dioxide - methane - inorganic fertilizers - fermentation - liming - netherlands - composts - sewage sludge - cultivation - crop residues - ripening
The National Emission Model for Agriculture (NEMA) is used to calculate emissions to air from agricultural activities in the Netherlands on a national scale. Emissions of ammonia (NH3) and other N-compounds (NOx and N2O) from animal housing, manure storage, manure application and grazing are assessed using a Total Ammoniacal Nitrogen (TAN) flow model. Furthermore, emissions from application of inorganic N-fertilizer, compost and sewage sludge, cultivation of organic soils, crop residues, and ripening of crops are calculated. NEMA is also used to estimate emissions of methane (CH4) from enteric fermentation and manure management, particulate matter (PM) from manure management and agricultural soils, and carbon dioxide
(CO2) from liming. Emissions are calculated in accordance with international guidance criteria and reported in an annual Informative Inventory Report (IIR; for air pollutants) and National Inventory Report (NIR; for greenhouse gases). This methodology report describes the outline and backgrounds of the emission
calculations with NEMA
Economic impact of the Commission's 'opt-out' proposal on the use of approved GM crops : quick assessment of the medium-term economic consequences
Hoste, R. ; Wagenberg, C.P.A. van; Wijnands, J.H.M. - \ 2015
LEI Wageningen UR (Report / LEI Wageningen UR 2015-097) - ISBN 9789086157259 - 51 p.
transgenic plants - crops - genetic engineering - soyabeans - economic impact - agricultural sector - food industry - feed industry - european union - france - germany - poland - hungary - transgene planten - gewassen - genetische modificatie - sojabonen - economische impact - landbouwsector - voedselindustrie - veevoederindustrie - europese unie - frankrijk - duitsland - polen - hongarije
The European Commission proposed the opportunity for individual EU Member States to restrict or prohibit the use of GMOs in food or feed on their territory (a national ‘opt-out’). The economic impact on individual sectors of the feed and food chain (the vegetable oil and meal industry, trade, animal feed industry, livestock sector) of a possible opt-out policy for soy by individual Member States has been assessed by LEI Wageningen UR.
A single scenario was defined in which the four countries France, Germany, Poland and Hungary choose an ‘opt-out’ policy for soy. Consequences of this switch to non-GM soy and substitutes were assessed both quantitatively and qualitatively for feed prices, for production costs for animal production, for crushing industry and for trade, with a focus on the medium term
Seed System Security Assessment in West Nile Sub region
Mastenbroek, A. - \ 2015
Centre for Development Innovation - 58 p.
seeds - food security - nile river - uganda - north africa - seed production - farmers' income - on-farm production - crops - acreage - regional development - supply chain management - zaden - voedselzekerheid - nijl - noord-afrika - zaadproductie - inkomen van landbouwers - productie binnen het landbouwbedrijf - gewassen - oppervlakte (areaal) - regionale ontwikkeling - ketenmanagement
The recommendations focus on the need to increase the availability of and access to quality seeds; improve quality, varietal sustainability and resilience of the seed system; build capacities of key actors to improve on their production and business skills; and address issues of enabling environment in seed security.
Effecten van een verbod op het gebruik van genetisch gemodificeerde soja als veevoedergrondstof. Quick scan van de gevolgen voor Nederland
Wagenberg, C.P.A. van; Hoste, R. - \ 2015
Wageningen : LEI Wageningen UR (LEI Report 2015-109) - ISBN 9789086157143 - 26
transgenic plants - crops - genetic engineering - soyabeans - fodder - economic impact - netherlands - transgene planten - gewassen - genetische modificatie - sojabonen - veevoeder - economische impact - nederland
If the Netherlands, alongside Germany, France, Poland, and Hungary, decides to ban genetically modified (GM) soy in animal feed, the use of soy products in animal feed in these five countries will have to decrease by 40 to 50% to ensure that the EU demand for non-GM soy does not exceed the supply on the world market. The extra costs to Dutch livestock farmers over a period of 3 to 5 years as a result of the more expensive non-GM soy and alternative protein sources are estimated at between €60 and €100 million a year, with approximately 80% being borne by poultry farmers. Livestock numbers and productivity will then be maintained. A partial shift in trade flows from animal feed ingredients can be expected from import in the west of the EU - for example, through the port of Rotterdam - to intra-EU flows from production areas within the EU to consumers and via the waterway axis from regions east of the EU, such as Ukraine. Less soy will enter the EU via the Netherlands. This deficit can be offset by the increased demand for alternative protein sources, which will be partly imported from overseas. The effects on Dutch ports, the transport sector, and employment will depend on the nature of the trade flow shifts.
Interpreting plant-sampled ¿14CO2 to study regional anthropogenic CO2 signals in Europe
Bozhinova, D.N. - \ 2015
University. Promotor(en): Maarten Krol; Wouter Peters, co-promotor(en): Michiel van der Molen. - Wageningen : Wageningen University - ISBN 9789462574946 - 155
kooldioxide - emissie - planten - atmosfeer - gewassen - plantensamenstelling - koolstofcyclus - methodologie - luchtkwaliteit - carbon dioxide - emission - plants - atmosphere - crops - plant composition - carbon cycle - methodology - air quality

"Interpreting plant-sampled Δ14CO2 to study regional anthropogenic CO2 signals in Europe"

Author: Denica Bozhinova

This thesis investigates the quantitative interpretation of plant-sampled ∆14CO2 as an indicator of fossil fuel CO2 recently added to the atmosphere. We present a methodology to calculate the ∆14CO2 that has accumulated in a plant over its growing period, based on a modeling framework consisting of a plant growth model (SUCROS) and an atmospheric transport model (WRF-Chem). We verify our framework against available atmospheric observations and use it to evaluate the ∆14CO2 budget of Europe, which is influenced by both fossil fuel CO2 and nuclear 14CO2 anthropogenic emissions. Finally, we present the results of the 14C analysis of samples of maize leaves that were obtained from the Netherlands, Germany and France in an experimental campaign conducted during 2010-2012. We use our modeling framework to interpret the ∆14CO2 signals of the samples and evaluate the different type of emission sources that have contributed for their final signatures.

Waterkwaliteit en landbouw: mag het ook een beetje zouter zijn?
Bakel, J. van; Kielen, N. ; Clevering, O.A. ; Roest, C.W.J. - \ 2015
H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 43 (2015)5. - ISSN 0166-8439 - p. 56 - 59.
bodemwater - zoutgehalte - normen - beschadigingen door droogte - gewassen - gewasverliezen - akkerbouw - agrohydrologie - bodemtypen - soil water - salinity - standards - drought injury - crops - crop losses - arable farming - agrohydrology - soil types
Door de te verwachten gevolgen van de klimaatverandering zal de zoetwatervoorziening van Nederland de komende jaren worden heroverwogen. Daarbij zijn de berekening van de zoutschade in de landbouw als gevolg van beregening met niet-zoet oppervlaktewater en de hantering van normen voor toelaatbare chlorideconcentraties in het oppervlaktewater belangrijke onderdelen. In 2009 is het hierop betrekking hebbende deel van het huidige Droogte-instrumentarium geëvalueerd, gebruik makend van het agrohydrologisch SWAP model. In het aandachtsgebied zijn vier gewassen (gras, aardappelen, suikerbieten en tulpen) op drie grondsoorten (zavel, zand en klei) het meest relevant. Als belangrijkste bevindingen dat de berekening van de zoutschade niet onjuist is, maar dat de gehanteerde normen voor toelaatbare chlorideconcentraties in het oppervlaktewater leiden tot te veel droogteschade en herziening behoeven
Is de landbouw echt zo gevoelig voor zout water?
Stuyt, L.C.P.M. ; Kielen, N. ; Ruijtenberg, R. - \ 2015
Water Matters : Kenniskatern voor Waterprofessionals - Dutch edition (2015)maart. - p. 39 - 42.
watervoorziening - brakwater - landbouw - zouttolerantie - gewassen - zuidwest-nederland - water supply - brackish water - agriculture - salt tolerance - crops - south-west netherlands
Hoe goed kunnen landbouwgewassen tegen brak water? Waterbeheerders hanteren in overleg met de landbouw al decennialang conservatieve normen voor zouttolerantie. Er zijn echter steeds meer aanwijzingen dat met name vollegrondsteelten (veel) beter tegen zout kunnen dan de normen suggereren. Er liggen grote kansen om het waterbeheer flexibeler en goedkoper te maken.
Atmospheric turbulence over crops : confronting theories with observations
Boer, A. van de - \ 2015
University. Promotor(en): Bert Holtslag, co-promotor(en): Arnold Moene; A. Graf. - Wageningen : Wageningen University - ISBN 9789462572416 - 143
turbulentie - meteorologie - atmosfeer - gewassen - watergebruiksrendement - transpiratie - modellen - eddy-covariantie - turbulente stroming - turbulence - meteorology - atmosphere - crops - water use efficiency - transpiration - models - eddy covariance - turbulent flow

Atmospheric turbulence plays a key role in hydrological and carbon cycles, and in weather and climate. Understanding and forecasting turbulence is thereby relevant for human life and environment.

We deal with some major challenges for studying atmospheric turbulence over crops. Land-atmosphere interactions are specifically complex because of surface heterogeneity. Also, boundary-layer entrainment complicates measuring and studying surface fluxes. Furthermore, the absence of high-frequency observations and of measurements of underlying soil and vegetation processes impedes studying land-atmosphere interactions.

We show the applicability of analytical footprint models over a heterogeneous land surface, and the validity of Monin-Obukhov similarity theory for a strongly-convective boundary-layer. Moreover, we present improvements on a scheme that can be used to estimate the amount of atmospheric turbulence from single-level weather data. We furthermore suggest to improve the partitioning theory that is used to distinguish soil processes from plant processes in eddy-covariance flux observations.

Information, trust and pesticide overuse: Interactions between retailers and cotton farmers in China
Jin, S. ; Bluemling, B. ; Mol, A.P.J. - \ 2015
NJAS Wageningen Journal of Life Sciences 72-73 (2015). - ISSN 1573-5214 - p. 23 - 32.
risk perceptions - bt cotton - knowledge - management - pest - workers - health - costs - crops - ipm
In the absence of adequate extension services, retailers have become the major information source for farmers’ pesticide use in rural China. Pesticide application for smallholders is rather complex, and mistakes can lead to significant crop losses. Farmers, therefore, seek sources of information regarding pesticide use. This paper first explores how different kinds of retailers may employ different strategies of providing information to farmers. We find that for village, town, and county retailers, the more familiar they are with farmers, the more likely they are to amplify the recommended dosage of pesticide use. In cooperatives, who buy pesticides from an extension station, the information is directly transferred to member farmers without information distortion. Apart from examining retailers’ different strategies of information provision, this paper also asks in how far farmers’ trust in retailers may affect pesticide use. It finds that trust in different kinds of retailers indeed varies and plays a critical role in converting information into farming behavior. Members of the cooperative show rather high levels of trust in their retailer, while farmers who are not members of a cooperative show low levels of trust in retailers. Pesticide use is a joint result of retailers’ information provision strategies and farmers’ trust. The lowest pesticide use occurs when accurate information is provided and when farmers highly trust the information provider. Overuse occurs with either information distortion or low levels of trust. Cooperatives have advantages both in terms of information provision and trust, thereby leading to the lowest use of pesticides.
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