The European Commission aims to “ensure 75% of soils are healthy by 2030” as part of its Soil Health and Food Mission.
At a recent Teagasc Land Use webinar, Giulia Bondi described a healthy soil as one that can perform functions such as water regulation, carbon storage, nutrient cycling, providing habitats for biodiversity and of course producing food all at the same time.
Carbon storage is something of increasing interest and Bondi explained that it is very difficult to measure as the build-up of carbon in the soil happens in very small quantities over long periods of time.
The Teagasc researcher made the important point that carbon which is applied to soil is released back to the atmosphere at some point in the near future and that the aim should be to slow down that release of carbon so that it stays in the soil for longer.
Bondi commented that in order to reduce carbon emissions from soil, soils should be managed carefully and she emphasised the importance of correcting nutrient imbalances to optimise productivity on soils high in carbon like grassland soils.
She also noted that soil compaction can reduce the potential to sequester carbon, emphasising again the importance for healthy soils to increase sequestration levels. Heavier machinery or extending the grazing season were outlined as two methods which can increase soil compaction levels.
Much of Ireland’s carbon is stored in peat soils. Peat soils take up approximately 20-25% of the landscape but are storing more than 53% of the carbon and Bondi added that selective remediation may be needed on these soils.
Bondi explained that 50% of soil organic matter is made up of carbon and estimated that globally 1,417 gigatonnes (Gt) of carbon are located in the first 1m of soil. 560Gt of carbon is located in the vegetation and 750Gt of carbon is in the atmosphere.