Concepts of Soil Formation and Classification in Arctic Regions

S' OME eighty years ago, when Dokuchaev (Margulis, 1954) distinguished five natural soil zones tundra, podzol, chernozem, desert, and laterite -the stage was set for a systematic study of soils as naturally occurring bodies. Of these, the tundra has received by far the least attention. European investigators, notably the Russians, have made many studies of the northern regions but in North America few reports of scientific studies in the Arctic have been made by trained soil scientists. In this paper some relationships of soil-forming processes operating in the various northern regions, especially in connection with the podzolic and the so-called tundra processes, are presented; and some problems in connection with vegetationsoil relationships and the classification and mapping of soils are outlined. In the formation of soil the most important factors that have to be taken into consideration are climate, parent material, biotic elements, relief, and time. The interaction of these five factors, operating at different intensities will produce soils with different properties. Given sufficient time, adequate drainage and depth of mineral material on the more level, stable landforms, a mature or zonal soil will tend to form. In the tropics the zonal soils will have a reddish appearance, in the prairies a dark brown to black, whereas in the northern forested regions the upper mineral horizons will have a bleached appearance. Distinct as these zonal soils are, they have at least one important feature in common, that is, they form under conditions of adequate drainage. Tundra soils, however, form under conditions of poor drainage and it may be somewhat fallacious to speak of them in terms of zonal soils as is done with podzols and chernozems.