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Submitted to: Agronomy Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 11/3/1995 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Over-winter freezing and thawing of soils in the northern U.S. causes movement of soil water and solutes in the soil profile. We conducted field and laboratory experiments using soil columns repacked in PVC plastic cylinders with 0.13 m inside diameter and 1.2 m length. Each column was packed with topsoil from a Webster silty clay loam to bulk densities of either 1.0 or 1.2 Mg/m**3. A potassium bromide tracer was placed in some of the columns. Twenty-four columns were buried vertically in a field near Ankeny, IA, during the 1994-95 winter and sampled in groups of four at roughly two-week intervals. Twelve columns were placed in a special freezing chamber where the top 0.3 m of soil in each column was frozen. Variables in the experiments were water content, soil bulk density, and the presence or absence of earthworms. The columns were sectioned into 0.05 m layers and analyzed for water content, bulk density, electrical conductivity, and bromide content. Water and solute movement varied with soil water content, bulk density, and the number of freeze/thaw cycles. This knowledge should aid in the development of effective overwinter management practices. |
