No abstract

Multivariate statistical procedures of numerical taxonomy were used to investigate the patterns of similarities among 59 soils. Twenty‐one morphological and laboratory characteristics of modal soil profiles from nine orders of the new classification system were used. Characters were selected to avoid high intercorrelations. Raw character values were transformed to give each character a mean of zero and variance of unity. Centroidcomponent analysis with projections of soils onto centroidcharacter axes was employed. This facilitated expression of similarities among soils in three dimensions in a manner which did not assume that clusters of soils existed. Correlation and distance matrices also were computed to obtain two estimates of the similarity of each individual to every other. Similarities among soils as indicated by these two matrices were summarized by cluster analysis. Results were displayed in phenograms yielding a system of nested clusters of soils.The three methods of estimating and summarizing similarity relationships gave comparable results. The numerical classifications agreed, in general, with the new classification system with respect to Mollisols, Alfisols, Inceptisols, Entisols, and Spodosols. Vertisols showed little affinity for one another, Aridisols clustered with Mollisols and Alfisols, and the single Oxisol clustered with Ultisols. Ultisols showed no special affinity for other Ultisols. Numerical taxonomic methods are capable of summarizing large amounts of new data efficiently, making them a valuable soil classification tool.

Briquets composed of sand (0.05–2.00 mm) silt (0.002–0.05 mm), and clay (<0.002 mm) mixtures were hardest when dominantly clay and/or sand and softest or least hard when dominantly silt. Where soils had equal amounts of clay, those with highest amounts of sand, with one exception, were the hardest. Low surface area of sand requires much less clay “mortar” to cement the fewer sand grains per given volume than do the more numerous, smaller silt particles.

Particle size analyses were made on 10 profiles representing four soil series. The profiles were located on a traverse perpendicular to the Missouri River from the Missouri River bluffs in northwestern Doniphan County, Kansas, to a point in southwestern Brown County, 24 miles from the river. The first sampling site was located 2 miles from the Missouri River. Subsequent sites were located at approximately 2½‐mile intervals. The thickness of the loess, as measured at most sites, decreased from approximately 100 feet at the river bluffs to 6 feet at the tenth site. The textural composition and pH of each horizon were determined in the laboratory. The texture of the C, B, and A horizons was observed to become finer with increased distance from the river up to 16 miles from the bluff. Beyond that point there was little if any decrease in particle size with distance. The change in texture of the C horizon with distance from the river appears to be the dominant factor in the development of the four soil series, Monona, Marshall, Sharpsburg, Grundy, which have not been finally correlated in this area. This work further substantiates the belief that the Missouri River Valley flood plain was a source of some of the loessial deposits of northeastern Kansas.