Funding of Century Agroecosystem Version 4.0 was provided by USDA-ARS Global Climate Change Research Program to the CRIS Project “Prediction of Long-term Changes in Carbon Storage and Productivity of U.S. Soils as Affected by Changes in Climate and Management”. The New Zealand Ministry of Agriculture and Fisheries provided the support of Alister Metherell for Ph. D. studies. We also acknowledge the support of EPA Project AERL 91-01 to Colorado State University and Michigan State University and NSF grand No. 8605191 to Colorado State Univeristy.

The Century model was developed as a project of the U.S. National Science Foundation Ecosystem Studies Research Projects “Organic Matter and Nutrient Cycling in Semiarid Agroecosystems” (DEB-7911988) and "Organic C, N, S, and P Formation and Loss from Great Plains Agroecosystems” (BSR-9105281 and BSR-8406628). The original model was described by Parton, Anderson, Cole, and Stewart (1983), with computer programming done by Vicki Kirchner. Additional support for model enhancement was provided by the Tallgrass Ecosystem Fire project (BSR-82007015), the Central Plains Experimental Range-Long Term Ecological Research project (BSR-8605191), the NASA-EOS project “Carbon Balance in Global Grasslands” (NAGW-2662), and the Agriculture Research Service USDA. Collaboration with scientists involved in international projects such as the Tropical Soil Biology and Fertility (UNESCO-TSBF) Programme and the Scientific Committee on Problems of the Environment (SCOPE) Project on “Effect of climate change on production and decomposition in coniferous forests and grasslands” also was instrumental in the development of Century.

Version 3.0, released in April of 1991, continued the development of Century with work done by W.J. Parton and programming by Rebecca McKeown. The support of William Parton, Dennis Ojima, Rebecca McKeown, and William Pulliam was critical for development of this version of Century.

Version 5 includes new physical soil, erosion, and deposition submodels, refined hydrology, and a modular design, whose development was funded in part by grants from the United States Geological Survey and the National Science Foundation.

The Century5 and DayCent5 User's Guide

The user's guide pages for Century5 and DayCent5 were developed by Tom Hilinski, based in large part upon the Century4 manual. Cindy Keough at NREL produced the Century4 manual in HTML format, and critically reviewed much of the initial document content.