Drumlin Landscapes

Drumlins, County Monaghan

You have probably heard of Drumlins from your study of glaciation, if not – check your textbook or this website for more detail on Ireland’s history as an ice-covered country. Ireland has gone through two glacial periods, the Munsterian (c 300,000 - 132,000 years ago) and the Midlandian (79,000 – 13,000 years ago). These glaciations left behind glacial deposits and landforms known as drumlins, which are smooth, oval shaped hills made up of boulder clay or till. As the glaciers covering Ireland retreated, they left these deposits behind, leaving behind a great deal of evidence. Drumlin comes from the Irish ‘dromnín’ meaning small hill. Though the exact process of drumlin formation is unknown, it is thought that glaciers became overloaded with sediment which was deposited as the power of the glacier lessened.

Drumlins are visible all over Ireland, particularly in the midlands and in low-lying areas. Soils in these areas tend to be poorly-drained when they are formed on low ground on dense glacial till which is wet and does not drain easily. It is also difficult to drain these landscapes as drumlins typically have slopes above 12°, which is difficult and dangerous for agricultural equipment to operate on.

The most common soils in drumlin landscapes tend to have a high clay content (40-60%) and have a heavy texture and weak structure, meaning the land-use these soils give rise to is limited to grassland or forestry, with rushes dominating the grasslands and machinery unable to work on the soils due to their weak structure making them vulnerable to compaction. It is certainly possible to use these soils for grazing, but it requires extensive management and the grazing season is not as long as it would be on a Brown Earth soil. While some drumlins are comprised of Brown Earth soil, the slope of the landscape still makes agriculture difficult, as machinery can’t operate safely, and lots of artificial nutrients are needed to keep the soil fertile.