Soil types in South Greenland
The sub and low Arctic soil in South Greenland is characterized by a lack of nutrients. The amount of available nutrients is determined by the relationship between their total amount in the soil, the rate at which they are broken down, and immobilizations. The mountains in South Greenland consist primarily of acidic rocks such as granite, gneiss and sandstone. Soils that develop from these rocks are acidic and low in nutrients. There is also basalt, and the pH neutral soils that form from these rocks are rich in nutrients.
The region is generally characterized by a slightly podsol type of soil with a low pH and small amounts of accessible plant nutrients. Larger concentrations of clay occur rarely, but considerable quantities of silt are often observable on the surface. There also occurs a certain amount of brown earth in inland areas.
Decomposition takes place slowly due to the low summer temperatures and predominantly acidic soil conditions. Soil analyses reveal low reaction numbers and low concentrations of phosphorus and potassium. The inner fjord areas generally have higher reaction numbers than the outer fjord areas, based in part on the lower amount of precipitation in inland areas and the addition of mineral soil in the form of loess ("glacial flour"). A limited amount of erosion occurs at some locations, particularly in areas near the edge of the ice cap.
Many types of soil have a limited capacity to absorb water, and occasionally there is a lack of precipitation, particularly in the inner fjord areas. Droughts occur during the summer, causing low course fodder yields and economic difficulties. Permafrost, which is defined as soil that is at or below the freezing point of water (0°C) for at least two years, is found sporadically in the lowlands of Southwest Greenland.