THE EFFECT OF ANTECEDENT FREEZE-THAW FREQUENCY ON RUNOFF AND SOIL LOSS FROM FROZEN SOIL WITH AND WITHOUT SUBSOIL COMPACTION AND GROUND COVER

Three soils from Prince Edward Island (a loam, a fine sandy loam, and a sandy loam) were tested under a laboratory rainfall simulator to examine the effects of frequency of freezing and thawing, winter rye cover, incorporated cereal residue, and subsoil compaction on runoff volume and sediment loss. Wooden soil boxes were subjected to simulated rain (i) at the end of a 10-d freezing period, and (ii) at the end of the 5th 24-h freezing period of a 10-d alternating freeze-thaw cycle (freeze/thaw). Where the soil was continuously frozen for 10 d, there was 178% greater sediment loss and 160% greater runoff than with daily freeze/thaw over the same period, but there was no difference in sediment concentration. Incorporated cereal residue decreased sediment loss to 50% and runoff to 77% of that from bare soil. Winter rye cover decreased sediment loss to 73% of that from bare soil. Simulated soil compaction caused a 45% increase in sediment loss. The loam soil showed 16.5% greater loss of fine sediment fractions <0.075 mm than the fine sandy loam which showed 23.4% greater loss than the sandy loam. Key words: Freeze-thaw, erosion, compaction, winter rye, cereal residue, rainfall simulator, Prince Edward Island soils