A study led by Teagasc has highlighted the "critical relationship" between the drainage status of peat soils, and localised rainfall in water table management.

According to Teagasc, these findings will be critical in identifying and targeting suitable sites for carbon water table management, and ultimately maximising carbon storage potential in agricultural grassland in peat soils.

Actively managing the water table of peat soils is an important tool to reach the EU target of climate neutrality by 2050.

As the water table of peat soils drop, carbon dioxide emissions increase, due to the introduction of oxygen to the system and the breakdown of organic matter.

During the ReWet project, researchers monitored six Irish peatland sites, four fens and two raised bogs between September 2023 and August 2024.

Using 30 monitored dip wells and hourly precipitation measurements, Teagasc investigated the relationship between water table rise, event rainfall and the water storage capacity of the soil.

Findings from Teagasc also revealed that fen peat sites were significantly more deeply drained than raised bogs, despite similar drainage system designs. The sites also varied in water storage capacity.

The water table in the raised bogs were less reactive to rainfall, drought, and artificial drainage.

On the other hand, fen peat sites were more deeply drained, and the water table was more reactive to rainfall inputs and seasonal variability.

Teagasc believes that this outcome reinforces previous endeavours to highlight the variability of drainage status within peat soils under grassland, of which there are approximately 340,000ha, 141,000ha of which are considered to be effectively drained, with an average water table greater than 30cm below the soil surface.

A proportion of grassland peat soils are being targeted for active water table management to reduce the average water table depth to within 30cm of the soil surface.

Head of Teagasc's climate centre, Karl Richards said: "This research underscores the need for site-specific peatland water management strategies that reflect the water table behaviour of different peat types.

"Such tailored approaches are essential for maximising carbon storage potential and supporting climate action across European grassland landscapes," Richards added.