Soils, weathering zones, and landscapes in the upland loess of Tama and Grundy counties, Iowa

Soil parent material stratigraphy and soil development, Cedar County, Iowa

“…The color range for the matrix of the deoxidized zone has been centered on a gray or light gray hue (Kay, 1916b;Ruhe, 1954;Ruhe et al, 1955;Ruhe and Scholtes, 1956;Daniels, Simonson, and Handy, I96I;Fenton, I966;Ruhe, 1969a). Fenton (1966) defined the colors of the deoxidized matrix.…”

“…The colors observed for an unoxidized matrix include dark gray, dark greenish gray, greenish gray, green, blue, and bluish gray (Kay, 1916a;Kay and Pearce, 1920;Kay and Apfel, 1929;Kay and Graham, 19^3;Huhe, 195^;Ruhe and Scholtes, 1956;Daniels et al, I96I;Fenton, I966;Ruhe, 1969a). Fenton (I966) defined the colors of the unoxidized matrix to include hues of 5Ï» 5GY, 5BG, and 5G having values of 4 and 5 with chroma of 0 and 1.…”

“…Oxidized zones have a free iron oxide content, defined chemically by the extraction with sodium hydro sulfite and expressed as an oxide, which vary from I.5 to 3»55^ (Ruhe, 1969a, p. 49). Extraction of free iron oxide by the sodium dithionite-sodium citrate method (Holmgren, 1967) from oxidized zones in loess has yielded values from 0.8 to I.7# (Fenton, I966;Huddleston, 1969;McKim, 1972).…”

“…Ruhe and his associates have continued to use the de oxidized term to imply "relict gleying" (Hall, 1965;Daniels and Jordan, 1966;Fenton, I966;Ruhe et al, 196? ;Ruhe et al, 1968;Ruhe, 1969a;Allen, 1971;Vreeken, 1972;Worcester, 1973).…”

“…Organic carbon values of 0.10 to 0.20^ have been reported in loessial oxidized and deoxidized zones from western Iowa (Daniels and. Handy, 1959;Ruhe, 1969a, p. 4-9 ;Allen, 1971. p. 63;Ruhe, Miller, Vreeken, 1971)-In other areas of Iowa OC values for the oxidized, deoxidized, and unoxidized zones have not been reported (Hall, 1965;Fenton, I966;Vreeken, 1972). Accumulations of OC in these weathering zones have not been reported because the investigators did not perform detailed analysis for OC on samples from these zones.…”