DAYCENT (Daily CENTURY Model)

Criterion	Explanation
General Description	Daily time-step version of the CENTURY biogeochemical model (version 4.0) used to simulate daily carbon and nitrogen gas fluxes between atmosphere, soil and vegetation for grassland, agricultural crop, forest and savanna systems.
Model Domain	General
Developer	Colorado State University, Natural Resources Ecology Lab.
Hardware computing requirements	Minimum requirements: 512K RAM, 220 KB to 2 MB disk capacity. Graphics adapter (CGA, EGA, VGA, or Hercules monographic) is recommended.
Code language	FORTRAN
Original application	Original model developed for simulation of carbon, nitrogen, phosphorus and sulfur dynamics in cultivated and uncultivated grassland soils (Parton et al., 1988).
Public/proprietary and cost	Model is publicly available, no associated cost for usage. The source code "DailyDayCent" is protected by a United States copyright to Colorado State University, all rights reserved; distribution and modification of this source code requires that permission is obtained from developer.
Physically or empirically based	Model physically based on established biogeochemical relationships.
Mathematical methods used	Model consist of various sub-models: soil water content and temperature by layer, net primary production allocation and plant production, decomposition (litter, soil organic matter), nutrient mineralization, nitrogen gas emissions due to nitrification and denitrification, and methane oxidation in non-saturated soils. Ecosystem processes generally expressed as algorithms or functions details can be found in Del Grosso et al., 2003; Parton et al., 1998; Alister et al., 1993.
Input data requirements	Daily maximum/minimum air temperature, daily precipitation, soil properties (bulk density, soil texture class, initial soil carbon, nitrogen, phosphorous and sulfur content), daily land management and vegetation data (vegetation type, cultivation and planting timeline, nutrient amendments, harvest practice, senescence, root type and distribution, vegetation productivity, C:N ratios, root to shoot ratios, lignin content), irrigation application, wet and dry nitrogen deposition and location coordinates. Meteorological, soil, land management and some vegetation data can be obtained from public databases, more specialized vegetation data can be obtained from pier reviewed literature.
Outputs	Daily gas flux (N₂O, NO_x, N₂, CO₂) soil organic carbon and nitrogen, nutrient cycling, net primary productivity, daily plant production, H₂O and NO₃ leaching and other ecosystem parameters. Output can be viewed in plot format provided with model application file.
Pre-processing and post-processing tools	Model application file.
Representation of uncertainty	Uncertainty not directly incorporated into model framework. Some evaluation of uncertainty in model predictions have been made using inverse modeling and comparison to observed data (Necpálová et al., 2015; Del Grosso et al., 2008; Del Grosso et al., 2005; Parton et al., 1998).
Prevalence	Model very commonly applied by academic institutes, less widely applied by government entities. Applications commonly include, but are not limited to, gas emission estimates, biomass production and emission mitigation for agricultural, tropical, pasture and deserts systems.
Ease of use for public entities	Easy to Moderate: no formal training required, user guides available. No specialized software needed.
Ease of obtaining information and availability of technical support	No commercial help desk available. User guide available at https://www2.nrel.colostate.edu/projects/daycent-downloads.html, user manual for CENTURY model available at http://www.nrel.colostate.edu/projects/century/century-downloads.php. Model workshop information available at https://www.nrel.colostate.edu/education/century-and-daycent-model-training-workshops/. Limited user support available through email (century@colostate.edu or century@nrel.colostate.edu).
Model and Source code availability	CENTURY model version 4.0 available at https://www2.nrel.colostate.edu/projects/daycent-downloads.html. More current versions of CENTURY model, DAYCENT model and source code "DailyDayCent" is available upon request from century@colostate.edu.
Status of model development	Model available to users via internet or upon request.
Challenges for integration	Integration challenges not clear. Model able to simulate output from various timesteps.

References

Alister K. Metherell, A.K., Harding, L.A., Cole, C.V., Parton, W.J., 1993. CENTURY Soil Organic Matter Model Environment Technical Documentation Agroecosystem Version 4.0. Available at http://www.nrel.colostate.edu/projects/century/century-downloads.php (accessed 22 October 2018).

Del Grosso, S.J., Halvorson, A.D. and Parton, W.J., 2008. Testing DAYCENT model simulations of corn yields and nitrous oxide emissions in irrigated tillage systems in Colorado. Journal of environmental quality, 37(4), pp.1383-1389.

Del Grosso, S.J., Mosier, A.R., Parton, W.J. and Ojima, D.S., 2005. DAYCENT model analysis of past and contemporary soil N2O and net greenhouse gas flux for major crops in the USA. Soil and Tillage Research, 83(1), pp.9-24.

Del Grosso, S.J., Parton, W., Ojima, D., Mosier, A., Keough, C.,2003. DAYCENT Model Overview, Testing and Application to Agroecosystems. Available at https://www2.nrel.colostate.edu/projects/daycent-downloads.html (accessed 22 October 2018).

Li, C., Six, J., Horwath, W.R. and Salas, W., 2014. Calibrating, Validating, and Implementing Process Models for California Agriculture Greenhouse Gas Emissions. California Environmental Protection Agency, Air Resources Board, Research Division.

Necpálová, M., Anex, R.P., Fienen, M.N., Del Grosso, S.J., Castellano, M.J., Sawyer, J.E., Iqbal, J., Pantoja, J.L. and Barker, D.W., 2015. Understanding the DayCent model: Calibration, sensitivity, and identifiability through inverse modeling. Environmental Modelling & Software, 66, pp.110-130.

Parton, W.J., Hartman, M., Ojima, D. and Schimel, D., 1998. DAYCENT and its land surface submodel: description and testing. Global and planetary Change, 19(1-4), pp.35-48.

Parton, W.J., Stewart, J.W. and Cole, C.V., 1988. Dynamics of C, N, P and S in grassland soils: a model. Biogeochemistry, 5(1), pp.109-131.

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