Removing GHG emissions
Agriculture is in a unique position with its potential to sequester carbon – removing carbon from the atmosphere and fixing it (for the long-term) in vegetation and soils. Ecosystems associated with agriculture are known to hold substantial carbon reserves; primarily in soil organic matter. Certain farm practices can facilitate increased plant uptake or soil storage of carbon (or reduce the loss of stored carbon). These practices sequester carbon or create carbon “sinks.” Agroforestry systems and perennial plantings may store significant quantities of vegetative carbon. Only vegetation retained over the long term is effective in storing carbon. Carbon sequestration practices include:
- Cropland management
- Grazing land and pasture management
Tillage & residue management
Tillage and residue management practices impact soil health and the organic content of soils. The following practices relate to greenhouse gas mitigation:
- Adopting conservation tillage –low-till or no-till practices
- Retaining crop residues (leaving plant residues on the soil surface to build soil carbon)
- Avoiding burning of residues (burning releases methane and nitrous oxide)
Grazing land & pasture management
Well managed pastures have healthier plants that produce more biomass and consequently take up more CO2. More digestible feed also decreases methane production in livestock. Improved pasture has the potential to increase feeding efficiency, reduce feed and reseeding costs and increase animal productivity.
Appropriate forage selection
Different forages are suited to different microenvironments. Selecting the best plant composition for pastures will improve their productivity and long-term sustainability.
Using rotational grazing keeps pasture at its most digestible stage (reducing emissions associated with enteric fermentation) and prevents overgrazing. Allowing vegetation to recover improves carbon sequestration potential, prevents erosion and improves pasture productivity.
Agroforestry is an intensive land management system that optimizes the benefits of the biological interactions that are created when trees and/or woody perennials are deliberately combined with crops and/or livestock.
The five main Agroforestry systems are:
- Shelterbelts & timberbelts
- Integrated riparian management
- Forest farming
These integrated systems have the benefit of diversifying sources of income (from timber or non-timber forest products) as well as contributing to greenhouse gas mitigation by sequestering carbon in trees (and potentially in soil).
Two agroforestry systems that have wide applicability for agricultural producers are shelterbelts and integrated riparian management.
Shelterbelts & timberbelts
Shelterbelts and timberbelts are managed rows of trees, shrubs and/or grasses adjacent to other agricultural practices (including windbreaks, hedgerows and fence line plantings) that provide a number of benefits including:
- Potential to fix carbon in soils and vegetation
- Protection of exposed buildings from heat loss or gain
- Shelter and shade for both wildlife and livestock
- Reduction in soil erosion, soil moisture loss and crop stress
- Timber and non-timber resources
Integrated riparian management
Integrated riparian management (IRM) is the management of areas adjacent to aquatic zones with planned combinations of trees and appropriate plant material to enhance and protect habitat while providing selective timber and non-timber resources.
IRM ensures maintenance of water resources, enhances bank stability, recharges groundwater and has the potential to sequester carbon. Appropriately managed riparian systems also retain the health of surrounding soils by moderating erosion and runoff.