Wetlands drainage could raise CO2 levels

THE future drainage of wetlands will have to be curtailed to prevent the loss of trapped greenhouse gases (GHG) from such soils.

This was one of the standout messages delivered at an Agricultural Science Association (ASA) conference last week on addressing climate change in Irish agriculture.

Professor Rogier Schulte, from Wageningen University and Research Centre in the Netherlands, told the conference that future applications for land drainage permits would have to be considered from a climate change perspective, as well as environmentally.

Prof Schulte said Ireland’s wetlands acted as sinks for soil organic carbon (SOC). This SOC could be oxidised, converted into CO2 and released into the atmosphere if the lands were disturbed during drainage and tilling.

The vast bulk of Ireland’s 1,500 million tonnes of SOC are in the country’s peat soil areas. Prof Schulte said controlling losses of SOC from these lands will have to be a future priority.

Scientists have already completed a map identifying ‘hotspots’ of SOC oxidisation, which shows areas that have been drained or otherwise disturbed.

Prof Schulte said maintaining these lands as SOC sinks will require the prevention of drainage, more extensive usage, or the rewetting of lands in some cases.

He suggested that these wetlands could be made eligible for environmental payments such as GLAS.

Prof Schulte also insisted that Ireland would have to increase its forestry cover from the current 11pc rate, which is the lowest in Europe.

In the keynote address to the conference, Dr Matthew Crowe of the Environmental Protection Agency (EPA) said that working towards “carbon neutrality in agriculture” had to be the goal of everyone involved in the industry.