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Elliott, J., Müller, C., Deryng, D., Chryssanthacopoulos, J., Boote, K. J., Büchner, M., et al. (2015). The Global Gridded Crop Model Intercomparison: data and modeling protocols for Phase 1 (v1.0). Geosci. Model Dev., 8(2), 261–277.
Abstract: We present protocols and input data for Phase 1 of the Global Gridded Crop Model Intercomparison, a project of the Agricultural Model Intercomparison and Improvement Project (AgMIP). The project includes global simulations of yields, phenologies, and many land-surface fluxes using 12-15 modeling groups for many crops, climate forcing data sets, and scenarios over the historical period from 1948 to 2012. The primary outcomes of the project include (1) a detailed comparison of the major differences and similarities among global models commonly used for large-scale climate impact assessment, (2) an evaluation of model and ensemble hindcasting skill, (3) quantification of key uncertainties from climate input data, model choice, and other sources, and (4) a multi-model analysis of the agricultural impacts of large-scale climate extremes from the historical record.
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Sharif, B. (2015). Inter-comparison of statistical models for projecting winter oilseed rape yield in Europe under climate change (Vol. 5).
Abstract: While intercomparison of process-based crop models for projections under climate change is being intensively studied at European as well as at the global scale, little effort has been made for comparing statistical models. In this study, several regression techniques (ordinary least squares, stepwise, shrinkage methods, principle components and partial least squares) were combined with different types of climate input variables (with different temporal resolution) in order to define a large range of statistical models. Each model was fitted to winter oilseed rape data collected in 689, 325 and 173 field experiments carried out in Denmark, Germany, and Czech Republic, respectively. The fitted models were then used to predict yield of winter oilseed rape in the field experiments during more than 20 years, up to 2013. Interpretability of the estimated climate variable effects and accuracy of yield predictions were both analysed. Results suggest that recent statistical methods (e.g., shrinkage methods) may have considerable capabilities to complement traditional statistical methods in yield prediction. The selection of the most influential variables was strongly influenced by the statistical method used to analyse the data. Among the most recent statistical methods, the uncertainties in projecting yield of winter oilseed rape under climate change were mainly due to residual errors and uncertainty in estimated parameter values, and not to model choice. No Label
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Kipling, R., Topp, K., & Don, A. (2015). The availability of carbon sequestration data in Europe (Vol. 4).
Abstract: With growing interest in the carbon sequestration potential of soils, experimental research and mapping projects have produced a wealth of datasets in this subject area. However, the coverage, quality and scope of available data vary widely across Europe, and the extent to which these data are accessible to experimental researchers and modellers is also highly variable. This report describes the availability of soil carbon data at the global and European levels, and reviews the on-line resources for accessing these data and meta-data. The extent to which researchers in the field share findings, based on institutional links in projects and on-line resources, is investigated. Future priorities for research and data accessibility relating to carbon sequestration are discussed. Many soil data resources are available online. Global and European soil data portals draw together much information from across Europe, and include the outcomes of major soil carbon mapping exercises. However, much project and national research is not accessible through these portals, and information on datasets derived from many research initiatives is difficult or impossible to locate online. Data on carbon sequestration (carbon fluxes in soils) specifically is more limited, although some such datasets are available through the general soil data resources described. Improved clarity in the presentation of research, and work to link more national and sub-national data to European and global online resources is required, with initiatives such as GSIF (Global Soil Information Facility) active in encouraging direct reporting of soil-related data at the global level. Priorities for research on SOC stocks include measuring carbon storage below the topsoil (>30cm), improving records of SOC in peatlands, improving the number and distribution of samples available for Europe-wide soil carbon mapping, and developing recognised methodological standards to allow easier comparisons of datasets. In the field of carbon sequestration research specifically, priorities include linking long-term SOC data to historical land use, developing understanding of the movement of SOC between top-soil and sub-soil and increasing dialogue between modellers and empirical researchers to improve dynamic modelling of SOC. No Label
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Dumont, B., Basso, B., Bodson, B., Destain, J. - P., & Destain, M. - F. (2015). Climatic risk assessment to improve nitrogen fertilisation recommendations: A strategic crop model-based approach. European Journal of Agronomy, 65, 10–17.
Abstract: Within the context of nitrogen (N) management, since 1950, with the rapid intensification of agriculture, farmers have often applied much larger fertiliser quantities than what was required to reach the yield potential. However, to prevent pollution of surface and groundwater induced by nitrates, The European Community launched The European Nitrates Directive 91/6/76/EEC. In 2002, in Wallonia (Belgium), the Nitrates Directive has been transposed under the Sustainable Nitrogen Management in Agriculture Program (PGDA), with the aim of maintaining productivity and revenue for the country’s farmers, while reducing the environmental impact of excessive N application. A feasible approach for addressing climatic uncertainty lies in the use of crop models such as the one commonly known as STICS (simulateur multidisciplinaire pour les cultures standard). These models allow the impact on crops of the interaction between cropping systems and climatic records to be assessed. Comprehensive historical climatic records are rare, however, and therefore the yield distribution values obtained using such an approach can be discontinuous. In order to obtain better and more detailed yield distribution information, the use of a high number of stochastically generated climate time series was proposed, relying on the LARS-Weather Generator. The study focused on the interactions between varying N practices and climatic conditions. Historically and currently, Belgian farmers apply 180 kg N ha(-1), split into three equal fractions applied at the tillering, stem elongation and flag-leaf stages. This study analysed the effectiveness of this treatment in detail, comparing it to similar practices where only the N rates applied at the flag-leaf stage were modified. Three types of farmer decision-making were analysed. The first related to the choice of N strategy for maximising yield, the second to obtaining the highest net revenue, and the third to reduce the environmental impact of potential N leaching, which carries the likelihood of taxation if inappropriate N rates are applied. The results showed reduced discontinuity in the yield distribution values thus obtained. In general, the modulation of N levels to accord with current farmer practices showed considerable asymmetry. In other words, these practices maximised the probability of achieving yields that were at least superior to the mean of the distribution values, thus reducing risk for the farmers. The practice based on applying the highest amounts (60-60-100 kg N ha(-1)) produced the best yield distribution results. When simple economical criteria were computed, the 60-60-80 kg N ha(-1) protocol was found to be optimal for 80-90% of the time. There were no statistical differences, however, between this practice and Belgian farmers’ current practice. When the taxation linked to a high level of potentially leachable N remaining in the soil after harvest was considered, this methodology clearly showed that, in 3 years out of 4,30 kg N ha(-1) could systematically be saved in comparison with the usual practice.
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Helming, J. (2015). Implementation of the GTAP emission database in MAGNET; applications at European and global scales (Vol. 5).
Abstract: World agriculture accounts for approximately 14% of all anthropogenic greenhouse gas. The share of agriculture in total greenhouse gas emissions in the EU 28 increased from 8.7% in 2007 to about 10.3% in 2012. This includes methane and nitrous oxide emissions (European Environment Agency; Gugele et al., 2005; Beach et al., 2008). This increase is mainly explained by emission reductions in the rest of the economy. Reductions in greenhouse gas emissions from agriculture remained limited in the recent past.Options to reduce emissions in agriculture depends on macro-economic trends, including international trade, agricultural policies, economic growth and consumption patterns. Global trade patterns will affect the regional distribution of agricultural production and the corresponding greenhouse gas emissions. The ability to introduce cost-effective measures to reduce greenhouse gas emissions are difficult to assess on a global scale. To tackle this problem there is a need for an interdisciplinary model instrument, in which both knowledge from macro and trade economy and natural sciences are included.The global equilibrium model MAGNET (Modular Applied GeNeral Equilibrium Tool) is developed by LEI and is an adaptation to the GTAP model (Woltjer & Kuiper, 2014). The main purpose of MAGNET is to provide a globally applied general equilibrium modelling framework, having the standard GTAP model as the core. MAGNET is complemented with the greenhouse gas emission dataset for the year 2007 that is made available by the GTAP consortium. The database includes emissions of carbon dioxide (CO2), nitrous dioxide (N2O) and methane (CH4). N2O and CH4 emissions are especially relevant for the agricultural sector. The incorporation of these emissions in MAGNET enables us to analyse current and future greenhouse gas emissions under different policies and mitigation measures on a global scale, simultaneously taking into account interactions between the rest of the economy (by sectors) and across regions in the world.The GTAP emissions dataset estimates the share of European agriculture in total greenhouse gas emissions in the EU 28 to be about 11.5% in 2007. This deviates from total emission figures on Europe as presented by the European Environment Agency (EEA). The presentation will focus on some possible explanations for this difference. We will compare gaps in the dataset in agriculture and the rest of the economy. Next we will report the emission per EU member state in a 2020 baseline scenario. Here we will present percentage differences in changes in greenhouse gas emissions in 2020 vis-a-vis a baseyear in 2012. No Label
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