Soil Carbon Sequestration
Carbon sequestration is the process of capturing carbon dioxide (CO2) from the atmosphere and storing it in soils or plant material such as trees and hedges. Agriculture is responsible for 27% of total Greenhouse Gas (GHG) emissions in NI, therefore, there is an increasing need to reduce the carbon footprint of our livestock-based production systems. Grasslands have the potential to store vast quantities of carbon in their soils in the form of soil organic matter.
Soil organic matter (SOM) forms due to the decomposition of plant and animal residues that enter the soil system which include leaf and straw residues, root material, soil organisms, and animal manure. Increasing organic matter levels in the soil will increase the soils carbon storage ability.
Methods to increase SOM and improve carbon sequestration on farm:
- Improve soil fertility levels; optimal soil pH, P, K status will improve grass productivity which in turn will enhance soil carbon
- Application of cattle slurry and FYM
- Optimise grazing management: Moderate grazing intensity over the grazing season can increase soil carbon by increasing the incorporation of grass residues and animal manure to the soil which stimulates shallow root growth
- Planting more diverse grassland swards: Incorporation of clover and deep-rooting species (plantain and, or chicory) into grassland swards will increase soil carbon storage deeper in the soil.
- Minimum cultivation: minimising soil disturbance during re-seeding will help to maintain soil organic matter stored in the soil.
CAFRE Soil Carbon Project
As grassland is the largest land use type in NI, accounting for more than 92% of agricultural land, there is real potential to improve our carbon storage and offset our GHG emissions. CAFRE are partaking in a project which aims to quantify soil carbon levels in farmlands and understand why and how these may change under common management practices (ploughing, reseeding, liming).
The project will focus on the effect of grassland management on soil carbon stocks at the dairy, beef and sheep farms at Greenmount. CAFRE have historical field records for a period of 50 years (crop history, reseeding, liming, fertiliser usage) for each field across the farms. This information will be used to select fields for soil sampling. Soil samples will be taken in each field to 30cm in depth to provide a baseline of soil C. Comparisons will be made between fields to determine relationships between management practices and soil C stocks. The findings from this project will feed into a NI wide project and help to deliver baseline data on soil C stocks across NI farms.