Dispersion Characteristics of Several Important Soil-Forming Materials in the United States

The purpose of this study is to examine differences in yields of clay following water dispersion and standard dispersion using a dispersing agent from soils formed in several parent materials in various areas of the United States. Dispersion characteristics of the following soils were studied: Typiic Hapludalfs, Typic Hapludolls, Udollic Ochraqualfs, Typic Haplaquolls, Terric Medisaprists, Typic Cryorthents, Typic Argiaquolls, Udic Argiustolls, Typic Glossaqualfs, Boralfic Argiborolls, Typic Haplargids, Typic Calciorthids, Cumulic Haplaquolls, Afic Haplorthods, Typic Medisaprists, Aeric Ochraqualfs, and Fluventic Haplustolls.These soils were selected from Illinois, Wisconsin, Iowa, Louisiana, Alaska, Montana, Nebraska, and New Mexico in order to provide soil materials having a range of dispersion characteristics.The soils studied formed in loess, glacial drift, and sediments derived largely from calcareous rocks. Preliminary observations in the laboratory suggested several general conclusions concerning the dispersion characteristics of these soils.(1) Loess-derived soils contain less water-dispersible clay than soils derived from glacial drift or soils derived from calcareous rocks.(2) Organic matter influences the yield of water-dispersible clay.(3) The amount and size of sand in the soil material influences the yield of water-dispersible clay. Additional measurements of clay determined by standard procedure for particle size analysis as well as following dispersion of soil with water along were made in an effort to refine the preliminary conclusions. Advisor: James V. Dre