Patrick Kavanagh’s famous rebuke of the “stony grey soils of Monaghan” could take on a whole new meaning in light of recent Teagasc research.

Lamenting that his early years were spent working the heavy ground of Inniskeen, Kavanagh claimed that the local rocky soils had effectively “burgled” his “bank of youth”.

Ironically, stony ground could be about to do a similar job on the carbon sequestration rates for soils, according to new research from Teagasc.

The study found that the presence of large quantities of stones in soils can lead to a serious overestimation of soil organic carbon (SOC). It said SOC values could be overstated by between 18% and 388%.

Bulk density

The research by Professor Owen Fenton and colleagues highlights the critical importance of soil bulk density estimations for SOC stocks, particularly in Irish grassland soils, which can have relatively high stone content.

Stones or rock fragments higher than 2mm in size made up between 0% and 36% of the soils examined. Since stones are mainly inert and do not interact with soil organic matter, their presence in soils affects the extent to which grasslands or tillage ground stores or loses carbon to the atmosphere.

The Teagasc team noted that quantifying changes in SOC, either carbon sequestration or losses into the atmosphere, requires accurate determination of soil bulk density, which is only achieved by accounting for soil stone content.

“Accurately measuring soil organic carbon and carbon content changes in soil over time requires more than the measurement of soil organic carbon concentration,” explained Prof Fenton, who is a principal research officer at Teagasc, Johnstown Castle.

Accurate methods

Commenting on the study’s findings, head of the Teagasc Climate Centre Dr Karl Richards said: “This Teagasc research underlines the importance of robust, reproducible and accurate methods to measure, report and verify soil organic carbon stocks on Irish farms.”

There have been mounting calls for an agreed methodology for measuring SOC stocks on farms and that farmers should be paid for increasing the level of carbon sequestration of their lands.