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The Voluntary Reporting of Greenhouse Gases-CarbOn Management Evaluation Tool (COMET-VR ) tool is a decision support tool for agricultural producers, land managers, soil scientists and other agricultural interests.

COMET-VR provides an interface to a database containing land use data from the Carbon Sequestration Rural Appraisal (CSRA) and calculates in real time the annual carbon flux using a dynamic Century model simulation.

Users of COMET-VR specify a history of agricultural management practices on one or more parcels of land. The results are presented as ten year averages of soil carbon sequestration or emissions with associated statistical uncertainty values. Estimates can be used to construct a soil carbon inventory for the 1605(b) program.

Click here to find information on how to start the COMET-VR Tool or use the navigation link "Help" at the top of the page.  You will need the following information about each parcel:

• The location;
• The area in English or Metric units;
• The land management type (i.e., Agricultural or Forest);
• The soil surface texture and hydric condition;
• The management history for four time periods.
   

Click Here! to start the Voluntary Report COMET-VR or use the navigation link "COMET-VR Tool" at the top of the page.

This updated version of COMET-VR has many new enhancements and many new rotations based on 1997 NRCS NRI data. These include non-irrigated and irrigated systems, which represent the dominant crop rotations in each region. Individual crop files were developed to represent higher grain yields, increases in plant bio-mass and nitrogen fertilizer additions. The updated COMET-VR has some new innovative cropping practices like the addition of "pulse" crops made up of field peas and green cover crops.

If you are using COMET-VR for your CSP reporting and find limitations in the current rotation selections you should contact your local NRCS representative for instructions or send an email to Roel Vining at roel.vining@por.usda.gov.  Mr. Vining can also be reached by calling 503-273-2410.  The new version of COMET-VR has the catch all category called "Other" that can be used to comply with CSP requirements. 

The carbon management tool is a collaborative research effort between USDA Natural Resources Conservation Service (NRCS) and Colorado State University, Natural Resource Ecology Lab (CSU NREL). Currently, the COMET-VR site is hosted by Colorado State University, NREL.

This tool estimates soil carbon changes for management alternatives for a ten year projection period within each Major Land Resource Area (MLRA) allowing users to estimate soil carbon sequestration on a parcel of land. The analysis is based on MLRA’s as defined by NRCS in Ag Handbook 296 (see table 1).  Data were reviewed and quality control measures assured that the highest quality inputs were used in the Century model analyses.

Ecosystem Model

Century is a generalized biogeochemical ecosystem model which simulates carbon (i.e., biomass), nitrogen and other nutrient dynamics. The model simulates cropland, grassland, forest and savanna ecosystems and land use changes between these different systems.  The Century Model was developed by Colorado State University (CSU) and USDA Agriculture Research Service (ARS). 

The Century model is widely used in the U.S. and in several other countries around the world for estimating national soil carbon inventories.  In previous work, NRCS and NREL have collaborated in using the model to estimate impacts of the Conservation Reserve Program (CRP) on soil carbon sequestration and to conduct county level soil carbon estimates for cropland in Iowa, Indiana, and Nebraska.