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Fallow Management and Overwinter Effects on Wind Erodibility in Southern Alberta
Author(s) -
Larney Francis J.,
Lindwall C. Wayne,
Bullock Murray S.
Publication year - 1994
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1994.03615995005800060030x
Subject(s) - tillage , loam , no till farming , summer fallow , environmental science , conventional tillage , aeolian processes , hydrology (agriculture) , agronomy , snow , soil water , mathematics , zoology , soil science , geology , geography , biology , meteorology , ecology , agriculture , soil fertility , geomorphology , geotechnical engineering , cropping
Aggregate size distribution (ASD) is influenced by tillage and climate and greatly affects wind erodibility of soils. This study determined the effects of fallow management and winter effects on ASD in the chinook belt of Alberta. Geometric mean diameter (GMD), geometric standard deviation (GSD), and erodible fraction (EF) <0.84 mm were determined in fall and spring on five fallow systems on a Lethbridge clay loam soil (fine‐loamy, mixed, Typic Haploboroll). The fallow systems were (i) tillage only, (ii) minimum tillage (herbicides and tillage), and (iii) zero tillage (herbicides only). In fall, one‐way disk and heavy‐duty cultivator fallow treatments had GMD values about 1 mm higher than blade cultivator or zero tillage treatments. The 1989–1990 winter with 90 cm of snowfall, 67 d of snow cover, and 101 d with a mean 2‐cm soil temperature between +2 and −2°C resulted in greater aggregate breakdown than the 1988–1989 winter, which had 129 cm of snowfall, 104 d of snow cover, and 68 d with 2‐cm soil temperatures between +2 and −2°C. Estimates of initiating wind velocities for erosion, based on residue cover and EF, were 13.3 m s −1 for the tillage treatments, 13.7 m s −1 for the minimum tillage treatment, and 15.4 m s −1 for the zero tillage treatment. However, the minimum and zero tillage systems had EF values >60% at more sampling times than the tilled treatments, indicating that wind erosion problems may occur if the residue cover was jeopardized.