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Agroforestry |
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Highlights for COMET2 - Carbon Management Evaluation Tool
COMET2 - Version: 2.1 is a significant upgrade of the previous COMET-VR Carbon Management Evaluation tool for soil C accounting on croplands and grazing land, with the inclusion of new modules for computing soil and biomass carbon stock changes for agroforestry practices and orchard/vineyards and a new module to estimate soil N2O emissions from cropland and grazing land management systems. Along with the "NEW" practices the online interface was streamlined making management input easier. Tillage and woody input options are now found on the "Management" input screen. The new COMET2 contains many new crop rotations based on USDA-NRCS National Resource Inventory (NRI) data and a variety of N management practices that can be implemented. The system allows for multiple fields/parcels to be included in the analysis and provides field-specific as well as whole farm/entity summary tables and reports. Both baseline (assuming current management) and land management change scenarios are estimated for a 10 year projection period.
Addition of Agroforestry and Orchard Modules
COMET2 allows users to generate soil and biomass carbon stock change estimates for agroforesty and perennial woody crops (i.e., orchards and vineyards) and conservation practices. Agroforestry options include all the major USDA-NRCS practices by region and the most common tree species used, all accessible from simple pull-down menus. The agroforestry module also includes an optional empirical model based on data from the US Forest Service’s Forest Inventory & Analysis (FIA) database, that allows users to enter measured data (e.g. species, stem diameters and density) to estimate changes in wood biomass C stocks. Orchard and vineyard management options include cover crop management, mulching and fertilization.
Updated Rotations and Management Scenarios
The COMET2 Tool now has many new management scenarios for agriculture developed from crop rotations reported in the USDA-NRI database for each Major Land Resource Area (MLRA) in the coterminous (48-state) US. More options are now available for specifying irrigated and non-irrigated systems for each region. A variety of nitrogen management options, for mineral fertilizer and manure, are now included (see information on N2O module below).
N2O emissions module
COMET2 provides estimates of soil N2O emissions using a meta-model based on the DayCent simulation model (which is used to compute N2O estimates for the US national GHG inventory). Users can specify N fertilizer and manure application rates (separately for each crop in the rotation), timing of application and use of nitrification inhibitors. N2O fluxes estimated by DAYCENT have been compared with field N2O flux data for different cropping systems to determine uncertainty estimates.
Updated Uncertainty Estimates
The COMET2 uncertainty estimates have been enhanced to include grazing systems as well as annual crops. Uncertainty estimates reported by COMET2 are representative of uncertainty at the spatial scale of Major Land Resource Areas (MLRA).
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