Freeze-thaw cycles increase near-surface aggregate stability

Lehrsch, Gary A. (1998) Freeze-thaw cycles increase near-surface aggregate stability. Soil Science. 163(1):63-70.

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Abstract

Soils with stable surface aggregates resist water and wind erosion better
than soils with unstable aggregates. From earlier studies, we had preliminary
evidence that one to three freeze-thaw cycles (FTCs) increased soil
aggregate stability when measured by wet sieving field-moist aggregates.
In this study, we measured the stability of aggregates vapor-wetted to field
capacity from the Ap horizons of four soils after undergoing either zero,
one, two, or four FTCs, and we determined the number of FTCs at which
aggregate stability would be greatest for each soil. Moist soil was packed to
a dry bulk density of 1.15 Mg M-3 by tapping it into 28-mm-diameter,
50-mm-tall brass cylinders. Each cylinder was then sealed in a polyethylene
bag and inserted into a polystyrene foam tray. The soil in each cylinder was
frozen convectively at —5°C for 48 h and then thawed at +6°C for 48 h for
each FTC. Aggregate stability increased with the first one to two FTCs but
changed little thereafter. Trend analysis revealed that aggregate stability
would be greatest after two or three FTCs. When averaged across the four
soils, FTCs stabilized aggregates more at 0 to 15 mm than at 15 to 30 mm.
Near the surface of wet soils, two or three FTCs may be beneficial rather
than detrimental to soil structure.

Item Type:	Article
NWISRL Publication Number:	0958
Subjects:	Soil Mass Import - autoclassified (may be erroneous)
Depositing User:	Users 6 not found.
Date Deposited:	20 Nov 2010 21:54
Last Modified:	21 Nov 2016 19:37
Item ID:	690
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/690