Annex 4 analytical methods

model description

general description

acronym: CENTURY

name: CENTURY agroecosystem dynamic model

main purpose: A biogeochemistry ecosystem model used to assess the impact of climate, land use and management practice changes on C budget of the EU agricultural soils.

homepage: http://www.nrel.colostate.edu/projects/century/

Developer and its nature

ownership: Third-party ownership (commercial companies, Member States, other organisations, …)

ownership additional info: Developed by Colorado State University. The version utilized is provided and maintained by prof. Paustian Lab Group (http://www.nrel.colostate.edu/paustian-group.html)

is the model code open-source?: NO

Model structure and approach with any key assumptions, limitations and simplifications

details on model structure and approach

CENTURY is a typical soil organic carbon (SOC) compartment model based on first order decay: the soil organic matter sub-model includes three SOC pools (active, slow and passive), along with two fresh residue pools (structural and metabolic), each with a different turnover rate. Soil temperature and moisture, soil texture and cultivation practices have different effects on these rates. The model is also able to simulate the water balance, using a weekly time step, and a suite of simple plant growth models are included to simulate C, N, P and S dynamics of crops, grasses and trees.

In our model framework, CENTURY is running at a resolution of 1 km2 in the agricultural soils of the EU, incorporating the most recently available pan-European datasets. The model can also be implemented with the soil erosion component. A daily time-step version of the model (DayCent) is recently running using the same JRC-D.3 model framework inputs.

The CENTURY model was spin-up through a series of management sequences encompassing the main agricultural technological stages of the last 2,000 years, until the actual management representing the business as usual scenario. A validation against the Land Use and Coverage Area frame Survey (LUCAS) soil samples was performed to test the model accuracy of the present SOC stock estimations.

model inputs

Key input to CENTURY are:

spatial distribution of the agricultural land use categories (arable, pasture, rice, permanent crops) (Source: Corine Land Cover 1990-2000-2006-2012)
soil texture, pH, bulk density, layers definition and depth, hydraulic properties (source: European Soil Database v.2 and LUCAS-derived spatial layers)
actual gridded climate (Source: European Climate Assessment & Dataset, E-OBS gridded weather dataset)
climate projections (Source: Coordinated Regional Climate Downscaling Experiment (CORDEX) climatic projections)
crop area distribution at NUT2 level, livestock density at NUT2, NUT3 level (source: EUROSTAT)
crop distribution, fertilizer consumption, irrigation, livestock density (Source: FAO)
soil erosion map (Source: Revised Universal Soil Loss Equation, RUSLE2015 (optional))

model outputs

Main outputs are:

soil organic carbon pools
biomass pools (grain, root, straw, etc.)
ecosystem variables (soil respiration, NPP, etc.)
eroded C
N fluxes including N2O emissions (DayCent)

Outputs are provided in raster format (geotiff).

Intended field of application

policy role

The model predicts the effect of different management practices on soil organic carbon (SOC) in agricultural soils, hence it may be used to compile regional/national C inventories and to support policies for C sequestration in soil.

The agricultural managements simulated by CENTURY consider the mineral and organic fertilizations, irrigation, grazing, crop rotation, tillage and harvest. Therefore, both, past changes (ex-post) on those practices (including land use change) and scenarios analysis (ex-ante) can be assessed by model runs.

policy areas

Agriculture and rural development
Climate action
Environment

Model transparency and quality assurance

Are uncertainties accounted for in your simulations?: YES - By multiple runs with sensitive inputs (soil datasets, climate change scenarios).

Has the model undergone sensitivity analysis?: YES - Not a fully sensitivity due to the model complexity, but for key inputs.

Has the model been published in peer review articles?: YES - The model has been published in peer-reviewed journals.

Has the model formally undergone scientific review by a panel of international experts?: NO - There has been no formal evaluation of the model by an external panel.

Has model validation been done? Have model predictions been confronted with observed data (ex-post)?: YES - Comparison against LUCAS soil data: comparison with meta-analyses.

To what extent do input data come from publicly available sources?: Entirely based on publicly available sources

Is the full model database as such available to external users?: NO - European Soil Data Centre (ESDAC).

Have model results been presented in publicly available reports?: NO

Have output datasets been made publicly available?: YES - Outputs are made available through the European Soil Data Centre.

Is there any user friendly interface presenting model results that is accessible to the public?: NO

Has the model been documented in a publicly available dedicated report or a manual?: YES

Intellectual property rights

Licence type: Non-Free Software licence

application to the impact assessment

Please note that in the annex 4 of the impact assessment report, the general description of the model (available in MIDAS) has to be complemented with the specific information on how the model has been applied in the impact assessment.

See Better Regulation Toolbox, tool #11 Format of the impact assessment report).