This week, researchers from Teagasc Moorepark and Teagasc Johnstown Castle published a new paper, which shows soil carbon levels in Irish grassland soils could be vastly underestimated.

This new research consisted of a field-scale study of 10 grassland dairy farms in Ireland, with a ‘heavy’ soil type and an average farm size of just over 52ha.

Higher than previous estimates

According to Teagasc, the average level of soil carbon present in these highly productive grassland farms was 346t/ha, which is significantly higher than previous estimates for soil carbon levels in Irish soils.

In some cases, the level of soil carbon found was up to four times higher than previous estimates.

“Current management has fostered the retention of large stores of soil carbon on such soils/farms which co-exist within highly productive farm systems,” the paper said.

In some cases, the level of soil carbon found was up to four times higher than previous estimates

The research also found that grassland soils on these highly productive dairy farms, which are already rich in carbon stocks, still have enormous potential to sequester and store more carbon from the atmosphere.

The paper suggested that, on average, the amount of carbon in these soils could be increased by a further 792t/ha before the soil reaches its carbon saturation potential.

In other words, there is potential to more than triple the amount of carbon in these already carbon-rich soils.

Teagasc recommends that high-carbon soils should be identified and new policies be developed in order to incentivise farmers to maintain and even increase soil carbon levels on their farms.

Nationwide study

While this latest study relates to just 10 grassland dairy farms, the research does highlight the significant amount of carbon already locked in Irish soils, as well as the enormous potential for increasing carbon capture from the atmosphere into these grassland soils.

The results of the Teagasc paper highlight more than ever the need to dramatically scale-up the level of research on soil carbon levels and soil carbon sequestration.

Irish grasslands clearly have the potential to become a major carbon sink in the years ahead.

However, without a better picture of the level of carbon sequestration potential nationwide and in all soil types, how can farmers be incentivised to make interventions that will suck more carbon out of the atmosphere and lock it away in their grassland soils?

A nationwide analysis of soil carbon levels is also critically important, in order to illustrate, for the first time, the sustainability of permanent grassland farms as part of a livestock system.

This is something Irish farmers have long argued for, and the results of the Teagasc study show more than ever that the Government needs to respond if it is serious about climate action.

As the Teagasc study notes, national scale assumptions for soil carbon levels that we currently use may help inform policy decision making but lack the local data measurement needed for farmers to make informed farm management decisions that will allow for increased carbon sequestration by Irish grassland soils.