The soil on which these studies were made was Southern Iowa loess from the experiment field in Decatur County, Iowa. It is a fine loess soil containing considerable clay with the silt, and enough organic matter in the surface to make it dark brown. This loess differs from that of both eastern and western Iowa in its color, which is grey rather than yellow. It is the prevailing type of soil in southern Iowa. The field from which the sample was taken had been in cultivation thirty or forty years, and in that time had probably produced no clover crops. The productiveness was quite low owing to continuous cropping with grain and poor cultural methods.
Proceedings of the Iowa Academy of Science
©1909 Iowa Academy of Science, Inc.
Watson, E. B.
"The Action of Manure on a Certain Iowa Soil,"
Proceedings of the Iowa Academy of Science, 16(1), 103-130.
Available at: https://scholarworks.uni.edu/pias/vol16/iss1/13