An economic activity or industry is the process of making a product or providing a service. Economic activities can be classified as primary, secondary, tertiary or quartenary.
Farmland like this in Country Down is common throughout Northern Ireland and is one example of a primary economic activity. Primary industries involve the sourcing of raw materials. Fishing, quarrying and forestry are other types of primary economic activity that can be found in Northern Ireland.
Farming or Agriculture is the most common primary industry in Northern Ireland.
There are both Arable farms- those that grow crops and Pastoral farms- those that specialise in rearing animals.
Commercial fishing is another type of primary economic activity. Kilkeel in County Down is one of Northern Ireland's main fishing ports. Here fish are landed and sold on for processing or to shops as wet fish. Many of the large buildings on each side of the harbour are fish processing factories which clean, freeze and pack the fish. 
Another type of primary activity is quarrying. The Sperrins contain deposits of sand and gravel left behind by glaciers at the end of the last Ice Age. These deposits can be quarried and used in the construction trade as well as in the building of roads. The material is dug out by excavators and diggers and then crushed and graded before being taken to be sold. There are over 160 quarries in Northern Ireland excavating sand, gravel and rock. 
Another type of primary activity is forestry. Forestry is usually found in upland areas like the Sperrins, because the soil is thin and poor and the climate too wet for farming. Coniferous trees are grown because they grow quickly and have straight trunks which make them easier to process. Trees are usually cut and sold about 30 - 40 years after they are planted. Forest areas will have stands of trees at different ages, planted at 5 year intervals. When one stand is cut and replanted another will be almost ready to cut.
An economic activity is the process of making a product or providing a service and can be classified as primary, secondary, tertiary or quartenary.
Primary industries involve the sourcing of raw materials. Farming, fishing, quarrying and forestry are types of primary economic activity.
Arable and pastoral farming is the most common primary industry in Northern Ireland.