Historic Management:
COMET-Farm requires users to enter historic management (pre-baseline) management before moving on to the baseline management pane. Information on historic land use, predating the start of the baseline period, is requested from the user to represent the longer-term trajectory of soil organic carbon (SOC) stocks. This is mainly to capture major changes in land use that have taken place in the last few decades. Users need only enter a very limited amount of information for past management history before the year 2000, using drop-down menus, from which they select the most representative choice for a given field. What if users don't know their historic management?
Baseline:
“Baseline” refers to a user’s current management, or “business as usual” management before a change in management occurs in the scenario period. COMET-Farm requires a minimum 5 year baseline for all cropland projects, but we recommend COMET-Farm users populate as much baseline management as possible for the best results. Even when using the Crop Rotation Builder, there is still an understanding that the user has some idea of crop type and general management occurring on the field during the baseline period.
When users do not have the necessary management for COMET-Farm, we typically recommend using COMET-Planner, which provides regional estimates of emission reductions based on conservation practices applied. For more information on how the data set for COMET-Planner was created, please refer to pages 7-10 in the report.
If a user does not have the necessary management for COMET-Farm, but still wants the farm-to-field level analysis/estimates this tool provides, we would recommend referring to the USDA-NASS Cropland Dataset to construct the crop rotation, and enlist the help of local resource conservation groups, extension and/or NRCS offices for any historic management records.