Submitted to: Seasonally Frozen Soils Symposium
Publication Type: Proceedings
Publication Acceptance Date: June 12, 1997
Publication Date: N/A
Technical Abstract: Aggregates within earthworm casts are usually more water stable than aggregates found in the bulk surface soil. Research has demonstrated that aggregate stability within earthworm casts varies among species of earthworms, soil texture, age of casts, and food sources. The objectives of this study were to examine the effects of freezing and thawing on the stability of intact (undisturbed) Lumbricus terrestris (L.) casts in different soils, under different soil moisture contents, and various freezing regimes compared to those in the bulk surface soil. Casts produced by L. terrestris were more water stable than the bulk surface soil. Stability was reduced when casts and bulk surface soil were frozen and then air dried. Air drying also reduced the stability of both the earthworm casts and the bulk surface soil. These studies are continuing and will aid in understanding the effects of earthworms and their casting activities on soil structure in soils that freeze.