Prior to the USDA's creation of the National Soil Taxonomy System in 1975, the only existent structure of differentiating soils was the British Soil Classification System, or BSCS, which divided up all soils in Great Britain into four primary categories: organic soils, fine soils, coarse soils and very coarse soils. Great Britain, including Ireland, still uses the BSCS to identify soil types based on appearance, content and particle size.
Very Coarse Soils
Very coarse soils appear primarily in the Province of Leinster. Individual particle sizes range from 60 mm to 400 mm and can be homogeneously packed with soils of their own type or mixed with coarse soils. Particles on the upper end of the scale are prone to voids or pockets when homogeneously packed, making it difficult for plant life to grow.
Coarse soils are divided up into gravel and sand categories. They are prominent in the Province of Munster. Gravel soils range from 2 to 60 mm in diameter, are easily visible to the naked eye, have a poorly graded range of sizes in any given area and can contain up to 35 percent clay or silt. Sands range from 0.06 to 2 mm in diameter, display more heterogeneous distributions of size, contain up to 50 percent clay or silt and form cohesive lumps when picked up.
Fine soils are found throughout all of Ireland. They are divided up into silt and clay categories. Silt soils have particles that are from 0.002 to 0.06 mm in diameter. Only the largest particles are visible to the naked eyes. They have a low plasticity, disintegrate in water, dry quickly, extrude between the fingers when squeezed and can contain between 35 and 65 percent gravel or sand. Clay soils have no visible particles and a homogeneous, highly plastic texture that can be easily molded. They also possess no more than 35 percent sand or gravel.
Organic soils are found in lowland areas such as bogs and swamps, Ulster being a prime example. As the name suggests, they are predominantly composed of decaying plant remains, eventually forming the spongy substance known as peat. The odor is distinct and cloying, while the color ranges from shining black to dark brown. Depending on the degree of decomposition and density, organic soils can range from being fibrous and still recognizable as plant matter to an amorphous sludge that smears the fingers and can be molded like clay.