Exchangeable Bases of Solonchak of the Red River Valley

EDITED areas of alkali soils are found scattered throughout the prairie portion of the Red River Valley in Minnesota. These have developed in poorly drained and swampy areas which were left when glacial Lake Agassiz receded. That the recession of the lake occurred in stages is shown by a series of old beaches which at varying distances more or less parallel the ancient short line (2, 6). These beaches are not continuous but represent a series of broken sand ridges, higher than the level of the plain on either side, which have obstructed the drainage between them and the outer edge or eastern side of the valley. Runoff and seepage water from the higher lying land to the east finds its way into this poorly drained area and maintains a relatively high water table. During the hot summer months much water is lost through evaporation leaving behind the salts carried in solution. In places these have accumulated in sufficient quantities to produce solonchak. The present paper reports a study of the characteristics of soil samples from five profiles of solonchak and suggests an explanation of changes involved in their desalinization which may, under certain conditions, lead to the formation of solonetz or under others to the elimination of this stage entirely.