Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 60

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==indexes
Check title to add to marked list
Distributed Evaluation of Local Sensitivity Analysis (DELSA), with application to hydrological models
Rakovec, O. ; Hill, M.C. ; Clark, M.P. ; Weerts, A.H. ; Teuling, A.J. ; Uijlenhoet, R. - \ 2014
Water Resources Research 50 (2014)1. - ISSN 0043-1397 - p. 409 - 426.
measuring uncertainty importance - coupled reaction systems - groundwater-flow system - net ecosystem exchange - parameter-estimation - information-content - rate coefficients - climate-change - land model - indexes
1] This paper presents a hybrid local-global sensitivity analysis method termed the Distributed Evaluation of Local Sensitivity Analysis (DELSA), which is used here to identify important and unimportant parameters and evaluate how model parameter importance changes as parameter values change. DELSA uses derivative-based “local” methods to obtain the distribution of parameter sensitivity across the parameter space, which promotes consideration of sensitivity analysis results in the context of simulated dynamics. This work presents DELSA, discusses how it relates to existing methods, and uses two hydrologic test cases to compare its performance with the popular global, variance-based Sobol' method. The first test case is a simple nonlinear reservoir model with two parameters. The second test case involves five alternative “bucket-style” hydrologic models with up to 14 parameters applied to a medium-sized catchment (200 km2) in the Belgian Ardennes. Results show that in both examples, Sobol' and DELSA identify similar important and unimportant parameters, with DELSA enabling more detailed insight at much lower computational cost. For example, in the real-world problem the time delay in runoff is the most important parameter in all models, but DELSA shows that for about 20% of parameter sets it is not important at all and alternative mechanisms and parameters dominate. Moreover, the time delay was identified as important in regions producing poor model fits, whereas other parameters were identified as more important in regions of the parameter space producing better model fits. The ability to understand how parameter importance varies through parameter space is critical to inform decisions about, for example, additional data collection and model development. The ability to perform such analyses with modest computational requirements provides exciting opportunities to evaluate complicated models as well as many alternative models.
How climate seasonality modifies drought duration and deficit
Loon, A.F. van; Tijdeman, E. ; Wanders, N. ; Lanen, H.A.J. van; Teuling, A.J. ; Uijlenhoet, R. - \ 2014
Journal of Geophysical Research: Atmospheres 119 (2014)8. - ISSN 2169-897X - p. 4640 - 4656.
hydrological drought - low flows - catchment - reanalysis - indexes
Drought propagation through the terrestrial hydrological cycle is associated with a change in drought characteristics (duration and deficit), moving from precipitation via soil moisture to discharge. Here we investigate climate controls on drought propagation with a modeling experiment in 1271 virtual catchments that differ only in climate type. For these virtual catchments we studied the bivariate distribution of drought duration and standardized deficit for the variables precipitation, soil moisture, and discharge. We found that for meteorological drought (below-normal precipitation), the bivariate distributions of drought characteristics have a linear shape in all climates and are thus not affected by seasonality in climate. Despite the linear shape of meteorological drought, soil moisture drought (below-normal storage in the unsaturated zone) and hydrological drought (below-normal water availability in aquifers, lakes, and/or streams) show strongly nonlinear shapes in drought characteristics in climates with a pronounced seasonal cycle in precipitation and/or temperature. These seasonality effects on drought propagation are found in monsoonal, savannah, and Mediterranean climate zones. In these regions, both soil moisture and discharge show deviating shapes in drought characteristics. The effect of seasonality on drought propagation is even stronger in cold seasonal climates (i.e., at high latitudes and altitudes), where snow accumulation during winter prevents recovery from summer hydrological drought, and deficit increases strongly with duration. This has important implications for water resources management in seasonal climates, which cannot solely rely on meteorology-based indices as proxies for hydrological drought duration and deficit and need to include seasonal variation in both precipitation and temperature in hydrological drought forecasting.
Identifying the methodological characteristics of European green city rankings
Meijering, J.V. ; Kern, K. ; Tobi, H. - \ 2014
Ecological Indicators 43 (2014). - ISSN 1470-160X - p. 132 - 142.
quality-of-life - environmental sustainability - composite indicators - urban areas - construction - pitfalls - indexes
City rankings that aim to measure the environmental sustainability of European cities may contribute to the evaluation and development of environmental policy of European cities. The objective of this study is to identify and evaluate the methodological characteristics of these city rankings. First, a methodology was developed to systematically identify methodological characteristics of city rankings within different steps of the ranking development process. Second, six city rankings European Energy Award, European Green Capital Award, European Green City Index, European Soot-free City Ranking, RES Champions League, Urban Ecosystem Europe were examined. Official websites and any methodological documents found on those websites were content analyzed using the developed methodology. Interviews with representatives of the city rankings were conducted to acquire any additional information. Results showed that the city rankings varied greatly with respect to their methodological characteristics and that all city rankings had methodological weaknesses. Developers of city rankings are advised to use the methodology developed in this study to find methodological weaknesses and improve their ranking. In addition, developers ought to be more transparent about the methodological characteristics of their city rankings. End-users of city rankings are advised to use the developed methodology to identify and evaluate the methodological characteristics of city rankings before deciding to act on ranking results.
Impact of diet and individual variation on intestinal microbiota composition and fermentation products in obese men
Salonen, A. ; Lahti, L.M. ; Salojärvi, J. ; Holtrop, G. ; Korpela, K. ; Duncan, S.H. ; Date, P. ; Farquharson, F. ; Johnstone, A.M. ; Lobley, G.E. ; Louis, P. ; Flint, H.J. ; Vos, W.M. de - \ 2014
ISME Journal 8 (2014). - ISSN 1751-7362 - p. 2218 - 2230.
gut microbiota - phylogenetic microarray - resistant starch - metabolic syndrome - health - bifidobacteria - bacterial - capacity - indexes - adults
There is growing interest in understanding how diet affects the intestinal microbiota, including its possible associations with systemic diseases such as metabolic syndrome. Here we report a comprehensive and deep microbiota analysis of 14 obese males consuming fully controlled diets supplemented with resistant starch (RS) or non-starch polysaccharides (NSPs) and a weight-loss (WL) diet. We analyzed the composition, diversity and dynamics of the fecal microbiota on each dietary regime by phylogenetic microarray and quantitative PCR (qPCR) analysis. In addition, we analyzed fecal short chain fatty acids (SCFAs) as a proxy of colonic fermentation, and indices of insulin sensitivity from blood samples. The diet explained around 10% of the total variance in microbiota composition, which was substantially less than the inter-individual variance. Yet, each of the study diets induced clear and distinct changes in the microbiota. Multiple Ruminococcaceae phylotypes increased on the RS diet, whereas mostly Lachnospiraceae phylotypes increased on the NSP diet. Bifidobacteria decreased significantly on the WL diet. The RS diet decreased the diversity of the microbiota significantly. The total 16S ribosomal RNA gene signal estimated by qPCR correlated positively with the three major SCFAs, while the amount of propionate specifically correlated with the Bacteroidetes. The dietary responsiveness of the individual’s microbiota varied substantially and associated inversely with its diversity, suggesting that individuals can be stratified into responders and non-responders based on the features of their intestinal microbiota.
Effects of growth pattern and dietary protein level during rearing on feed intake, eating time, eating rate, behavior, plasma corticosterone concentration, and feather cover in broiler breeder females during the rearing and laying period
Emous, R.A. van; Kwakkel, R.P. ; Krimpen, M.M. van; Hendriks, W.H. - \ 2014
Applied Animal Behaviour Science 150 (2014)1. - ISSN 0168-1591 - p. 44 - 54.
food restriction - welfare assessment - improve - indexes - hunger - age - performance - parameters - allocation - chickens
An experiment was conducted to evaluate the effect of growth patterns (GP) and dietary crude protein levels (CP) during rearing (2–22 weeks of age) on feed intake, eating time, eating rate, behavior, plasma corticosterone concentration, and feather cover in broiler breeder females during the rearing and laying period. A total of 768 day-old Ross 308 broiler breeder chicks, of which 288 hens were followed during the laying period, were allotted to 6 different treatments during the rearing period according to a 2 × 3 factorial design, with 8 replicates (pens) per treatment. Two growth patterns were followed by a restricted feeding regime up to a target body weight (BW) at 20 weeks of age of 2200 g (standard growth pattern = SGP) and 2400 g (high growth pattern = HGP) and 3 dietary protein levels (high = CPh, medium = CPm, and low = CPl). During lay, all birds were fed a standard breeder diet and followed a standard growth pattern. During rearing, HGP birds were fed on average 6.5% more feed than SGP birds. In HGP birds, eating time (min/day) during the rearing period increased by 17%, whereas eating rate (g feed/min) decreased by 8%, compared to SGP birds. This prolonged feeding behavior of HGP birds, but stereotypic object pecking and animal pecking was not reduced. Feather cover was not affected by growth pattern during the rearing and laying period. Only at 16 weeks of age a lower plasma corticosterone concentration was found for the HGP birds. HGP birds showed more feeding and sitting behavior, but less foraging behavior during the rearing period, while during the laying period only more walking behavior was observed. In order to maintain target weights, feed intake levels of CPm and CPl during rearing were set 4.6 and 10.0% higher than CPh, whereas eating time was increased by 22 and 63% and eating rate was decreased by 9 and 26%, respectively. A prolonged eating time during rearing for CPm and CPl birds resulted in more time spend feeding and resting and less stereotypic object pecking and animal pecking compared to CPh birds during rearing. In contrast to the rearing period, feed intake and eating time were not affected by CP level during rearing at 22 weeks of age, whereas eating rate was increased by 8 and 16% for CPm and CPl, respectively, compared to CPh. At 27 weeks of age the effect of CP level during rearing on eating rate had disappeared. Plasma corticosterone concentrations were not affected by dietary protein level during the rearing and laying period. Feather cover was inferior by lowering the dietary protein level, in particularly during the first 11 weeks of rearing. No effect of GP was found on feather cover. It is concluded that dietary protein levels positively affected some behavioral traits during the rearing period, whereas these traits were only slightly affected by growth patterns. However, the physiological parameter (plasma corticosterone concentration) was not affected.
Spatial precipitation patterns and trends in The Netherlands during 1951–2009
Daniels, E.E. ; Lenderink, G. ; Hutjes, R.W.A. ; Holtslag, A.A.M. - \ 2014
International Journal of Climatology 34 (2014)6. - ISSN 0899-8418 - p. 1773 - 1784.
neerslag - klimaatverandering - statistische analyse - regionale verkenningen - seizoenen - nederland - precipitation - climatic change - statistical analysis - regional surveys - seasons - netherlands - coastal precipitation - urban land - europe - rainfall - temperatures - extremes - feedback - impacts - indexes - soils
Significant increases in precipitation have been observed in The Netherlands over the last century. At the same time persistent spatial variations are apparent. The objective of this study is to analyse and explain these spatial patterns, focussing on changes in means and extremes for the period 1951–2009. To investigate different possibilities for the causes of spatial variations, a distinction was made between six regions based on mean precipitation, soil type and elevation, and four zones at different distances to the coast. Spatial maxima in mean precipitation inland and over elevated areas are mainly formed in winter and spring, while maxima along the coast are generated in autumn. Daily precipitation maxima are found in the central West coast and over elevated areas. Upward trends in daily precipitation are highest from February to April and lowest from July to September. The strongest and most significant increases are found along the coast. For several seasonal and climatological periods diverging behaviour between coastal and inland zones is observed. We find that distance to the coast gives a more consistent picture for the seasonal precipitation changes than a classification based on surface characteristics. Therefore, from the investigated surface factors, we consider sea surface temperature to have the largest influence on precipitation in The Netherlands.
Ervaringen met kengetal en dagdoseringen in melkveehouderij
Kuipers, A. ; Wemmenhove, H. - \ 2013
Veehouder en Veearts 27 (2013)1. - p. 28 - 30.
melkveehouderij - antibiotica - dosering - indexen - registratie - dairy farming - antibiotics - dosage - indexes - registration
Afgelopen paar jaar is het aantal dagdoseringen als kengetal voor antibioticagebruik ingevoerd. Wat kun je daar nu mee? In dit artikel geven we impressies van enkele toepassingen.
Groeien in rendement : hulpmiddelen om rendabeler te groeien
Zijlstra, Jelle - \ 2013
dairy farming - farm management - milk production - investment - indexes - financial management
Normen en economische waarderingen voor: de rentabiliteitsindex 2012 en het productiegetal 2013 zeugenhouderij
Animal Sciences Group (ASG), - \ 2013
[Lelystad] : Livestock Research Wageningen UR - 6
varkenshouderij - zeugen - rentabiliteit - indexen - bedrijfsresultaten in de landbouw - normen - prestatieniveau - pig farming - sows - profitability - indexes - farm results - standards - performance
Wageningen UR Livestock Research berekent jaarlijks de waarderingsnormen voor de rentabiliteitsindex en het productiegetal voor de zeugenhouderij. Dit vindt plaats in opdracht van het Productschap Vee en Vlees (PVV). In het kort wordt beschreven wat de rentabiliteitsindex en het productiegetal voor de varkenshouder betekenen. Vervolgens worden in het kort de berekeningsmethode en de uitgangspunten voor de berekeningen van de waarderingsnormen uiteengezet. Met behulp van deze waarderingsnormen zijn de rentabiliteitsindex en het productiegetal per individueel bedrijf te berekenen.
Normen en economische waarderingen voor: de rentabiliteitsindex 2012 en het productiegetal 2013 vleesvarkenshouderi
Animal Sciences Group (ASG), - \ 2013
[Lelystad] : Livestock Research Wageningen UR - 6
varkenshouderij - vleesproductie - rentabiliteit - indexen - bedrijfsresultaten in de landbouw - normen - prestatieniveau - pig farming - meat production - profitability - indexes - farm results - standards - performance
Wageningen UR Livestock Research berekent jaarlijks de waarderingsnormen voor de rentabiliteitsindex en het productiegetal. Dit vindt plaats in opdracht van het Productschap Vee en Vlees (PVV). In het kort wordt beschreven wat de rentabiliteitsindex en het productiegetal voor de varkenshouder betekenen. Vervolgens worden in het kort de berekeningsmethode en de uitgangspunten voor de berekeningen van de waarderingsnormen uiteengezet. Met behulp van deze waarderingsnormen zijn de rentabiliteitsindex en het productiegetal per individueel bedrijf te berekenen.
Buffercapaciteit : bedrijfsstijlen in de melkveehouderij, volatiele markten en kengetallen
Oostindië, H.A. ; Ploeg, J.D. van der; Broekhuizen, R.E. van - \ 2013
Wageningen : Wageningen UR etc. - 50
melkveehouderij - melkprijzen - agrarische bedrijfsvoering - bedrijfssystemen - karakteristieken - veehouders - indexen - buffercapaciteit - dairy farming - milk prices - farm management - farming systems - characteristics - stockmen - indexes - buffering capacity
Dit rapport doet verslag van een statistische analyse uitgevoerd op een bestand van Nederlandse melkveehouderijbedrijven. Het doel van deze analyse was na te gaan wat de effecten waren van de melkprijsdaling, die zich voordeed in de tweede helft van 2008 en de eerste helft van 2009. De toenmalige prijsdaling beschouwen we als een voorbode van de situatie die steeds meer de zuivelmarkt zal typeren: een volatiele markt met scherpe prijswisselingen. Het onderzoek toont aan dat de effecten van een melkprijsdaling differentieel van aard zijn, ze variëren al naar gelang het type bedrijf. Om deze verschillen te vatten is een bedrijfsstijlenanalyse uitgevoerd die 4 strategische grondpatronen naar voren brengt: schaalvergroting, fijnregulering, kostenreductie en arbeidsbesparing. In ‘normale’ jaren kan via elk strategisch grondpatroon een goed inkomen worden verworven. Naarmate men meer ‘stijlspecifiek’ is, is het inkomen beter. In ‘slechte’ jaren ligt dit anders: dan blijken strategieën, die draaien om kostenreductie en fijnregulering, tot de beste resultaten te leiden. Ook de balans van vreemd en eigen vermogen speelt in slechte jaren een grote rol. Op haar beurt hangt die balans ook weer op significante wijze samen met de verschillende stijlen. Daarmee brengt de analyse een verschil naar voren dat in de komende jaren wellicht van groot belang zal worden: dat is het verschil tussen boerenlandbouw en ondernemerslandbouw. Met dit onderscheid wordt hier geen moreel of maatschappelijk oordeel gegeven. Waar het om gaat is de vraag welke vorm van landbouwbeoefening het best moeilijke marktomstandigheden weet te weerstaan. In de tweede helft van dit verslag staat de vraag centraal: welk kengetal biedt de melkveehouder het meeste houvast om na te gaan of zijn bedrijf over voldoende veerkracht beschikt om periodes van lage prijzen het hoofd te bieden? Er wordt een nieuw kengetal voorgesteld: buffercapaciteit. Daarnaast kijken we bij welke bedrijfsopzet (stijl) de buffercapaciteit het hoogst is en hoe deze verder is op te voeren
Betere sturing met vernieuwde kengetallen varkenshouder
Vermeij, I. ; Holster, H.C. - \ 2012
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 678) - 141
varkenshouderij - zeugen - vleesvee - beren (varkens) - indexen - standaardisering - registratie - bedrijfsvergelijking in de landbouw - pig farming - sows - beef cattle - boars - indexes - standardization - registration - farm comparisons
Dit rapport bevat een gedetailleerde beschrijving van de afspraken, die gemaakt zijn voor het uniform berekenen en presenteren van kengetallen voor varkensbedrijven (versie 2012). In deze versie zijn de technische en economische kengetallen beschreven voor zowel de zeugenhouderij, de vleesvarkenshouderij als voor combi-varkensbedrijven. De noodzaak van uniform berekende kengetallen wordt behalve door de behoefte aan externe bedrijfsvergelijking, steeds meer ingegeven door de behoefte aan interne bedrijfsvergelijking.
Monitoring Least Weasels after a Winter Peak of Lemmings in Taimyr: Body Condition, Diet and Habitat Use
Feige, N. ; Enrich, D. ; Popov, I.Y. ; Broekhuizen, S. - \ 2012
Arctic 65 (2012)3. - ISSN 0004-0843 - p. 273 - 282.
stable-isotopes - dicrostonyx-groenlandicus - dynamics - nitrogen - residuals - greenland - abundance - selection - ecology - indexes
Least weasels are highly specialized small-rodent predators. Despite the fact that they are hypothesized to play an important role in generating the lemming cycles, a key process for the functioning of the terrestrial tundra ecosystem,. very little is known about the biology of these miniature carnivores in the Arctic. At Mys Vostochny in western Taimyr, Russia, least weasels were observed for the first time during a lemming peak in 2005, but not in two subsequent years with low lemming densities. Here we report observations about weasel signs in lemming winter nests, body condition, habitat use, and diet in summer 2008, a year when lemmings had been numerous under the snow but populations crashed before the summer, and least weasels were abundant. Stable isotope analyses revealed that weasel diet was dominated by Siberian lemmings during spring. As expected, given lower resource availability when the lemming population crashed, weight (taking into account body length) was somewhat lower in 2008 than in 2005. Tracking tunnels and trapping showed that in summer least weasels mostly used sheltered habitats such as rocky outcrops and driftwood. Together with surveys of lemming winter nests, tracking tunnels appeared to be a promising method for monitoring least weasels in the Arctic tundra.
Exploring variation in economic, environmental and societal performance among Dutch fattening pig farms
Dolman, M.A. ; Vrolijk, H.C.J. ; Boer, I.J.M. de - \ 2012
Livestock Science 149 (2012)1-2. - ISSN 1871-1413 - p. 143 - 154.
egg-production systems - welfare quality(r) project - sustainability indicators - indexes
Sustainable production of pork requires farms that are economically viable, ecologically sound and socially acceptable, both now and in the future. Promising mitigation options to improve the integrated sustainability of a pig farm can be deduced from variation in their economic, environmental and societal performance. This study explores the variation in sustainability performance among 27 specialized fattening pig farms in the Dutch Farm Accountancy Data Network. Moreover, the combined sustainability performance is quantified, in order to identify the characteristics of best performing farms. To quantify the economic performance we used the net farm income (NFI) and labor productivity. With a life cycle assessment (LCA) the environmental performance was quantified for land occupation (LO), non-renewable energy use (NREU), global warming potential (GWP), eutrophication potential (EP) and acidification potential (AP). To quantify the societal performance the usage of antibiotics and the pig mortality rate were used. The average NFI was -€3.1 per 100 kg slaughtered weight (SW), produced with a labor productivity of 0.4 h per 100 kg SW. To produce 100 kg of SW, a total LO and NREU were needed of respectively 1121 m2 and 2802 MJ. GWP was 546 kg CO2-eq per 100 kg SW, of which 31% CO2, 7% from CH4, and 62% from N2O. Total EP was 61.4 kg NO3--eq/100 kg SW, of which 53% from leaching of nitrate and 23% from phosphate. Total AP was 5.3 kg SO2-eq per 100 kg SW, of which 79% NH3, 11% from NOx and 10% from SO2. The use of antibiotics per 100 kg SW averaged 18.9 daily dosages per animal year. The number of deceased pigs per 100 kg SW averaged 0.03. There is a high variation in economic, environmental and societal performance among fattening pig farms. Farm characteristics related to scale positively affect economic and environmental performance. A low feed intake and a feeding ration with a high share of wet by-products positively affect the environmental performance. To identify explanatory farm characteristics from FADN for societal performance, more suitable indicators are needed. Best performing farms, which outperform on economic, environmental and societal performance do exist and are on average larger and are feeding a higher proportion of by-products. To understand the characteristics of an integrative sustainable fattening pig farm, more insight is needed in the entrepreneurial characteristics and the drivers to manage and perform in a more profitable, environmental friendly and societally acceptable way.
Predicting soil N mineralization using organic matter fractions and soil properties: A re-analysis of literature data
Ros, G.H. - \ 2012
Soil Biology and Biochemistry 45 (2012). - ISSN 0038-0717 - p. 132 - 135.
nitrogen mineralization - indexes - availability - management - relevance - systems
Extractable organic matter (EOM) fractions have been used to assess the capacity of soils to supply nitrogen (N), but their role in N mineralization and their potential to improve agricultural fertilizer management are still under debate. This paper shows evidence that the relationship between EOM and soil N supply is an indirect relationship reflecting the soils’ organic matter content. Data from 59 published experiments were re-analyzed using multivariate PLS modelling. Nitrogen mineralization was primarily related to the size of total and extractable organic matter fractions whereas variables reflecting soil texture and organic matter quality were less important. All EOM fractions reflected the soil organic matter content of the soil rather than a specific bioavailable fraction. There is strong need for research that explores the biochemical basis for relationships among total organic matter, extractable organic matter and soil N mineralization using mechanistic approaches.
Identifying plant species using mid-wave infrared (2.5-6µm) and thermal infrared (8-14µm) emissivity spectra
Ullah, S. ; Schlerf, M. ; Skidmore, A.K. ; Hecker, C. - \ 2012
Remote Sensing of Environment 118 (2012)4. - ISSN 0034-4257 - p. 95 - 102.
salt-marsh vegetation - hyperspectral data - biomass estimation - reflectance - discrimination - indexes - imagery - leaves - classification - spectroscopy
Plant species discrimination using remote sensing is generally limited by the similarity of their reflectance spectra in the visible, NIR and SWIR domains. Laboratory measured emissivity spectra in the mid infrared (MIR; 2.5µm-6µm) and the thermal infrared (TIR; 8µm-14µm) domain of different plant species, however, reveal significant differences. It is anticipated that with the advances in airborne and space borne hyperspectral thermal sensors, differentiation between plant species may improve. The laboratory emissivity spectra of thirteen common broad leaved species, comprising 3024 spectral bands in the MIR and TIR, were analyzed. For each wavelength the differences between the species were tested for significance using the one way analysis of variance (ANOVA) with the post-hoc Tukey HSD test. The emissivity spectra of the analyzed species were found to be statistically different at various wavebands. Subsequently, six spectral bands were selected (based on the histogram of separable pairs of species for each waveband) to quantify the separability between each species pair based on the Jefferies Matusita (JM) distance. Out of 78 combinations, 76 pairs had a significantly different JM distance. This means that careful selection of hyperspectral bands in the MIR and TIR (2.5µm-14µm) results in reliable species discrimination.
The potential of spectral mixture analysis to improve the estimation accuracy of tropical forest biomass
Basuki, T.M. ; Skidmore, A.K. ; Laake, P.E. van; Duren, I.C. van; Hussin, Y.A. - \ 2012
Geocarto International 27 (2012)4. - ISSN 1010-6049 - p. 329 - 345.
urban vegetation abundance - landsat tm data - aboveground biomass - satellite estimation - kyoto protocol - indexes - amazon - carbon - reflectance - information
A main limitation of pixel-based vegetation indices or reflectance values for estimating above-ground biomass is that they do not consider the mixed spectral components on the earth's surface covered by a pixel. In this research, we decomposed mixed reflectance in each pixel before developing models to achieve higher accuracy in above-ground biomass estimation. Spectral mixture analysis was applied to decompose the mixed spectral components of Landsat-7 ETM+ imagery into fractional images. Afterwards, regression models were developed by integrating training data and fraction images. The results showed that the spectral mixture analysis improved the accuracy of biomass estimation of Dipterocarp forests. When applied to the independent validation data set, the model based on the vegetation fraction reduced 5 – 16% the root mean square error compared to the models using a single band 4 or 5, multiple bands 4, 5, 7 and all non-thermal bands of Landsat ETM+.
Normen en economische waarderingen voor: de rentabiliteitsindex 2011 en het productiegetal 2012 zeugenhouderij
Animal Sciences Group (ASG), - \ 2011
[Lelystad] : Livestock Research Wageningen UR - 6
varkenshouderij - zeugen - rentabiliteit - indexen - bedrijfsresultaten in de landbouw - normen - prestatieniveau - pig farming - sows - profitability - indexes - farm results - standards - performance
Wageningen UR Livestock Research berekent jaarlijks de waarderingsnormen voor de rentabiliteitsindex en het productiegetal voor de zeugenhouderij. Dit vindt plaats in opdracht van het Productschap Vee en Vlees (PVV). In het kort wordt beschreven wat de rentabiliteitsindex en het productiegetal voor de varkenshouder betekenen. Vervolgens worden in het kort de berekeningsmethode en de uitgangspunten voor de berekeningen van de waarderingsnormen uiteengezet. Met behulp van deze waarderingsnormen zijn de rentabiliteitsindex en het productiegetal per individueel bedrijf te berekenen.
Normen en economische waarderingen voor: de rentabiliteitsindex 2011 en het productiegetal 2012 vleesvarkenshouderi
Animal Sciences Group (ASG), - \ 2011
[Lelystad] : Livestock Research Wageningen UR - 8
varkenshouderij - vleesproductie - rentabiliteit - indexen - bedrijfsresultaten in de landbouw - normen - prestatieniveau - pig farming - meat production - profitability - indexes - farm results - standards - performance
Wageningen UR Livestock Research berekent jaarlijks de waarderingsnormen voor de rentabiliteitsindex en het productiegetal. Dit vindt plaats in opdracht van het Productschap Vee en Vlees (PVV). In het kort wordt beschreven wat de rentabiliteitsindex en het productiegetal voor de varkenshouder betekenen. Vervolgens worden in het kort de berekeningsmethode en de uitgangspunten voor de berekeningen van de waarderingsnormen uiteengezet. Met behulp van deze waarderingsnormen zijn de rentabiliteitsindex en het productiegetal per individueel bedrijf te berekenen.
Waar staan de biologische melkveehouders?
Nauta, W.J. - \ 2011
V-focus 8 (2011)6. - ISSN 1574-1575 - p. 30 - 32.
melkveehouderij - biologische landbouw - indexen - vragenlijsten - statistische gegevens - dairy farming - organic farming - indexes - questionnaires - statistical data
In 2009 en 2010 zijn de biologische melkveehouders binnen het onderzoek ‘Type koe – type bedrijf’ gevraagd een enquête in te vullen, waarin bedrijfskengetallen, specifieke managementaspecten en fokkerijdoelstellingen centraal stonden. Van de 320 bedrijven hebben 180 bedrijven aan de enquête meegedaan. Op basis hiervan wordt in dit artikel een beeld van de huidige biologische melkveehouderij gegeven.
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.