The Holos model is a software application that estimates greenhouse gas (GHG) emissions and changes in soil carbon (C) in Canadian farming systems. The model’s development focusses on enhancing the environmental sustainability of Canadian farming by testing, validating, and providing sustainability attributes for Canadian agricultural production systems.

Based on information entered for individual farms, the main purpose of Holos is to test possible ways of reducing GHG emissions and increasing soil C stocks by exploring the effects of different management practices. 

A tool to estimate and reduce GHGs from farms

In the Holos model interface, users can ‘build’ their model farm using the available cropping, livestock, and machinery components, and then create scenarios that best describe their operation. Model settings and management practices can be adjusted to examine the effect on GHG emissions and soil C. Examples of these adjustments include changing livestock diets, reducing tillage or including perennial forages in a rotation.

Once information is entered into the program, Holos estimates net emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), in carbon dioxide equivalents, calculated for the various farm components. The sources of emissions include enteric fermentation and manure management, cropping systems and energy use. Carbon storage and loss from fields used for grazing and crop production and lineal tree plantings and are also estimated in response to changes in land use and management. The model includes 36 commonly grown annual and perennial crops, summer fallow, native rangeland, tame pasture and 8 types of tree plantings, along with beef, dairy, sheep, swine, poultry and other livestock operations. The model relies on extensive climate, soil, and agronomic databases to populate regionally-applicable default values. The result is a GHG and soil C estimate for the whole farm that can help the user identify ways to reduce farm emissions.

Holos is continually being updated with new data and improved features and is available at no cost to users. The most current version of Holos is version 4.0, available in both English and French.

Holos 4.0 Installation Package

We welcome feedback from researchers, farmers, and industry to help us improve this software. The team is preparing the model for collaborative development (now open source) and is thus looking for opportunities to involve the expertise of other groups outside of AAFC to facilitate their inclusion in future versions.

User documentation and a frequently asked questions (FAQ) page is available on the Holos GitHub website.

For more information on Holos, please contact holos@agr.gc.ca.


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