SGS-LTER East Pawnee National Grassland Chronosequence 1999-2000

EPNG Chronosequence - Representative soils of seven Pleistocene and Holocene age Platte River stream terraces were characterized. The area is located on the eastern fringe of the PNG. A backhoe was used to excavate soil pits to a depth of 2 m. Pedons were described and sampled by genetic horizon and analyzed at the National Soil Survey Laboratory, Lincoln, Nebraska. Analyses included: particle size (including fractionation of sand, silt and clay); bulk density (paraffin covered clod method, Blake and Hartge, 1986); pH (1:1 saturated paste); CaCO3 ( samples treated with HCl and evolved CO2 measured manometrically; dithionate-citrate extractable Fe, Mn and Al; clay mineralogy; total elemental analysis for K, Ca, Mg, Si, Al, Fe, and P were determined by selective dissolution techniques. Organic C was determined at Colorado State University using a Leco CHN analyzer after soils were acidified with 0.1M HCl. Total, inorganic, and organic P fractions were determined at Colorado State University using a modified version of the Hedley sequential extraction method (Tiessen et al., 1984) taken from Crews et al. (1995).