Regional crop modelling in Europe: The impact of climatic conditions and farm characteristics on maize yields   总被引：1，自引：0，他引：1  

Pytrik Reidsma  Frank Ewert  Hendrik Boogaard  Kees van Diepen 《Agricultural Systems》2009,100(1-3):51-60

Impacts of climate variability and climate change on regional crop yields are commonly assessed using process-based crop models. These models, however, simulate potential and water limited yields, which do not always relate to observed yields. The latter are largely influenced by crop management, which varies by farm and region. Data on specific management strategies may be obtained at the field level, but at the regional level information about the diversity in management strategies is rarely available and difficult to be considered adequately in process-based crop models. Alternatively, understanding the factors influencing management may provide helpful information to improve simulations at the regional level.In this study, we aim to identify factors at the regional level that explain differences between observed and simulated yields. Observed yield data were provided by the Farm Accountancy Data Network (FADN) and Eurostat. The Crop Growth Monitoring System (CGMS), based on the WOFOST model, was used to simulate potential and water limited maize yields in the EU15 (i.e., the old member states of the European Union). Differences between observed and simulated maize yields were analysed using regression models including: (i) climatic factors (temperature and precipitation), (ii) farm size, (iii) farm intensity, (iv) land use, (v) income and (vi) subsidies. We assumed that the highest yields observed in a region were close to the yield potential as determined by climate and considered the average regional yields as also influenced by management. Model performance was analysed with respect to spatial and temporal yield variability.Results indicate that for potential yield, the model performed unsatisfactory in southern regions, where high temperatures increased observed yields which was in contrast to model simulations. When considering management effects, we find that especially irrigation and the maize area explain much of the differences between observed and simulated yields across regions. Simulations of temporal yield variability also diverted from observed data of which about 80% could be explained by the climatic factors (35%) and farm characteristics (50%) considered in the analysis. However, effects of specific factors differed depending on the regions. Accordingly, we propose different groups of regions with factors related to management which should be considered to improve regional yield simulations with CGMS.  相似文献   

Local eradication of Haemonchus contortus using closantel     

IA BARGER  E. HALL  KM DASH 《Australian veterinary journal》1991,68(10):347-348

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Multi-drug resistant Escherichia coli with extended-spectrum β -lactamase activity and fluoroquinolone resistance isolated from clinical infections in dogs     

AL WARREN  KM TOWNSEND  T KING  S MOSS  D O''BOYLE  RM YATES  DJ TROTT 《Australian veterinary journal》2001,79(9):621-623

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The effect of temporal aggregation of weather input data on crop growth models’ results     

L.G.J. van Bussel  C. Müller  H. van Keulen  F. Ewert  P.A. Leffelaar 《Agricultural and Forest Meteorology》2011,151(5):607-619

Weather data are essential inputs for crop growth models, which are primarily developed for field level applications using site-specific daily weather data. Daily weather data are often not available, especially when models are applied to large regions and/or for future projections. It is possible to generate daily weather data from aggregated weather data, such as average monthly weather data, e.g. through a linear interpolation method. But, due to the nonlinearity of many weather-crop relationships, results of simulations using linearly interpolated data will deviate from those with actual (daily) data. The objective of this study was to analyse the sensitivity of different modelling approaches to the temporal resolution of weather input data. We used spring wheat as an example and considered three combinations of summarized and detailed approaches to model leaf area index development and associated radiation interception and biomass productivity, reflecting the typical range of detail in the structure of most models. Models were run with actual weather data and with aggregated weather data from which day-to-day variation had been removed by linear interpolation between monthly averages.Results from different climatic regions in Europe show that simulated biomass differs between model simulations using actual or aggregated temperature and/or radiation data. In addition, we find a relationship between the sensitivity of an approach to interpolation of input data and the degree of detail in that modelling approach: increasing detail results in higher sensitivity. Moreover, the magnitude of the day-to-day variability in weather conditions affects the results: increasing variability results in stronger differences between model results. Our results have implications for the choice of a specific approach to model a certain process depending on the available temporal resolution of input data.  相似文献   

Ecosystem service supply and vulnerability to global change in Europe   总被引：12，自引：0，他引：12  

Schröter D  Cramer W  Leemans R  Prentice IC  Araújo MB  Arnell NW  Bondeau A  Bugmann H  Carter TR  Gracia CA  de la Vega-Leinert AC  Erhard M  Ewert F  Glendining M  House JI  Kankaanpää S  Klein RJ  Lavorel S  Lindner M  Metzger MJ  Meyer J  Mitchell TD  Reginster I  Rounsevell M  Sabaté S  Sitch S  Smith B  Smith J  Smith P  Sykes MT  Thonicke K  Thuiller W  Tuck G  Zaehle S  Zierl B 《Science (New York, N.Y.)》2005,310(5752):1333-1337

Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.  相似文献   

Mycotic dermatitis with digital gangrene and osteomyelitis,and protozoal intestinal parasitism in Marlborough green geckos (Naultinus manukanus)     

BD Gartrell  KM Hare 《New Zealand veterinary journal》2013,61(5):363-367

CASE HISTORY: Thirty adult Marlborough green geckos (Naultinus manukanus) were collected from Stephens Island and held over winter, prior to their translocation. Five adult geckos developed skin lesions after husbandry changes affected the humidity of their enclosures. Two geckos underwent ecdysis and recovered. One animal died and two others progressively worsened and were presented for treatment.

CLINICAL AND PATHOLOGICAL FINDINGS: The geckos were in poor body condition and had multiple black powdery lesions and solitary raised white nodules on their skin. Both geckos died despite topical and supportive treatment. Histopathology showed the skin nodules contained branching non-septate hyphae infiltrating necrotic epidermal tissue, and associated dermal inflammation. There was necrosis of several digits and mycotic osteomyelitis. Mucor ramosissimus was cultured from skin biopsies from each animal. Large numbers of motile protozoa, resembling Trichomonas, and another unidentifiable, were recovered from fresh faecal smears, and Nyctotherus sp protozoa were present in the lumen of the intestine of one animal post mortem.

DIAGNOSIS: Mycotic dermatitis with digital gangrene and osteomyelitis due to Mucor ramosissimus, and enteric protozoal parasitism with Trichomonas sp and Nyctotherus sp.

CLINICAL RELEVANCE: The clinical course and pathological findings of mycotic dermatitis in two Marlborough green geckos involved in a wildlife translocation in New Zealand are reported, and also the first record of the Marlborough green gecko as a host for the enteric protozoa Trichomonas sp and Nyctotherus sp.  相似文献   

Detection of Mycoplasma conjunctivae in sheep affected with conjunctivitis and infectious keratoconjunctivitis     

MXJ Motha  J Frey  MF Hansen  R Jamaludin  KM Tham 《New Zealand veterinary journal》2013,61(4):186-190

AIM: To determine the aetiolog y of a recurring and severe form of infectious keratoconjunctivitis (IKC) in sheep.

METHODS: Five sheep flocks that had experienced a severe form of IKC were examined. Clinical history, conjunctival swabs and blood samples were collected from affected animals. Culture for bacteria, and also specifically for Mycoplasma and Chlamydophila spp, and detection of Mycoplasma conjunctivae DNA by polymerase chain reaction (PCR) were attempted. Serum samples were tested for antibodies to M. agalactiae, M. capricolum, M. conjunctivae and Chlamydophila spp.

RESULTS: Mycoplasma conjunctivae DNA was detected using PCR in 3/5 flocks, and in all flocks antibodies to M. conjunctivae were detected in sera. A pure growth of Branhamella ovis was cultured from conjunctival swabs from a small proportion of sheep in two flocks. No other pathogens were detected.

CONCLUSIONS: This investigation demonstrated that M. conjunctivae was a primary pathogen causing severe IKC in sheep, and is the first report of detection of this organism in sheep in New Zealand. Introduction of clinically normal carrier sheep appeared to have caused the outbreaks.  相似文献   

Pitfall or priority drift? Participatory tree domestication programs: The case of agroforestry in the Peruvian Amazon     

Thorsten Wiersberg  Frank Ewert 《Journal of Sustainable Forestry》2013,32(7):486-499

ABSTRACT

The Agroforestry Tree Domestication Program was globally launched in the 1990s by the World Agroforestry Center to increase farmers’ living standards and slow deforestation. After 20 yr of operation, we screen the impacts on farmers’ livelihoods and prospects in one of the implementation sites: the Ucayali region of the Peruvian Amazon. We contrast the viewpoints of two sets of stakeholders: (a) “outsiders”—scientists, technicians, and development workers; and (2) “insiders”—local farmers organized and not organized. Group and semistructured interviews were used for data collection, and system analyses were conducted for their integration and interpretation. Results diverge by subset. “Outsiders” praised the program lastingness but questioned its dependence on external parties for management; they considered land property and product marketing keys to persist and succeed. In contrast, “insiders” considered the program financially not viable as well as third-party and locally dependent. As an alternative they had initiated activities, both forestry related and otherwise, to profit from their acquired technical and managerial skills. Based on these findings, broadening stakeholders’ diversity and set conveniently roles and decision power during the rationale and implementation phases of similar initiatives could prevent such divergences.  相似文献   

A new mite IPM strategy: predator avoidance behaviour resulting from the synergetic effects of predator release and acaricide‐treated nets     

Miriam Kungu  Emilie Deletre  Sevgan Subramanian  Komi KM Fiaboe  Linus Gitonga  Zipporah Osiemo Lagat  Thibaud Martin 《Pest management science》2019,75(4):979-985

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Sensitivities to DMI fungicides in populations of Podosphaera fusca in south central Spain     

Francisco J López‐Ruiz  Alejandro Pérez‐García  Dolores Fernández‐Ortuño  Diego Romero  Emilio García  Antonio de Vicente  James KM Brown  Juan A Torés 《Pest management science》2010,66(7):801-808

BACKGROUND: Cucurbit powdery mildew elicited by Podosphaera fusca (Fr.) U Braun & N Shishkoff limits crop production in Spain. Disease control is largely dependent on fungicides such as sterol demethylation inhibitors (DMIs). Fungicide resistance is an increasing problem in this pathogen. To overcome such risk, it is necessary to design rational control programmes based upon knowledge of field resistance. The aim of this study was to investigate the state of DMI sensitivity of Spanish P. fusca populations and provide tools for improved disease management. RESULTS: Using a leaf‐disc assay, sensitivity to fenarimol, myclobutanil and triadimenol of 50 isolates of P. fusca was analysed to determine discriminatory concentrations between sensitive and resistant isolates. As no clearly different groups of isolates could be identified, discriminatory concentrations were established on the basis of maximum fungicide field application rate, 100 mg L^?1 for the three fungicides tested. Subsequently, a survey of DMI resistance was carried out in different provinces located in the south central area of Spain during the cucurbit growing seasons in 2002, 2003 and 2004. Examination of a collection of 250 isolates revealed that 23% were resistant to fenarimol and 7% to triadimenol, the provinces of Almería, Badajoz and Murcia being the locations with the highest frequencies of resistance. By contrast, no resistance to myclobutanil was found. CONCLUSION: Results show that fenarimol and, to a lesser extent, triadimenol have become less efficient for controlling cucurbit powdery mildew in Spain. These are important observations that should lead to reconsideration of the current disease management programmes. Copyright © 2010 Society of Chemical Industry  相似文献