Effect of freezing and thawing processes on some physical properties
of saline–sodic soils mixed with sewage sludge or ﬂy ash
, Ilker Angin, Fatih M. Kiziloglu
Ataturk University, Faculty of Agriculture, Department of Agricultural Structures and Irrigation, 25240 Erzurum, Turkey
Soils that are experienced by freeze–thaw processes are
most susceptible to dispersion during the late winter and
early spring. Freezing and thawing of the soil mass have a
very important effect on soil structure. Consecutive
freeze–thaw cycles in soil may affect aggregation either
positively or negatively. Demolishment of soil structure
and aggregation due to freeze–thaw processes were
reported by many researchers (Edwards, 1991; Lehrsch
et al., 1991; Staricka and Benoit, 1995; Hanay et al., 2003;
Oztas and Fayetorbay, 2003; Sahin and Anapali, 2007).
Sodicity also causes destruction of the soil structure and
consequently reduce the soil hydraulic conductivity (Ilyas
et al., 1997; Ishiguro and Nakajima, 2000). The suscept-
ibility of soils to sodicity and low salinity depends on both
inherent properties of soils and extrinsic, time-dependent
properties (Oster and Shainberg, 2001). Hanay et al. (2003)
found that freeze–thaw cycles negatively effects hydraulic
conductivity especially in clay soils which have high-
exchangeable sodium percentage (ESP) content.
Effect of freezing and thawing on wet aggregate stability
is not important in soils which have high-exchangeable
sodium percentage and electrical conductivity. In thecase of
high-electrical conductivity and relatively low-exchange-
able sodium percentage, wet aggregate stability greatly
inﬂuences by freeze–thaw cycles (Sahin and Anapali, 2007).
Soil & Tillage Research 99 (2008) 254–260
Received 4 September 2007
Received in revised form 11 January 2008
Accepted 2 March 2008
Wet aggregate stability
Dispersion of saline–sodic soils was rather difﬁcult to leach. Therefore, negative effects of
freeze–thaw on soil physical properties should be reduced by inexpensive and practical
methods. This study investigates the effect of freeze–thaw cycles (3, 6, and 9) on wet
aggregate stability, bulk density, and permeability coefﬁcient in three soils with different
electrical conductivity and exchangeable sodium percentage levels (soil I: 5.30 dS m
47.51%; soil II: 42.80 dS m
, 55.45%; soil III: 36.30 dS m
, 59.34%) which consist of
different proportions of sewage sludge and ﬂy ash by volume (10%, 20%, and 30%). The
experiment was conducted under laboratory conditions using disturbed and non-cropped
soil samples mixed with sewage sludge and ﬂy ash. Soils mixed with sewage sludge
produced higher aggregate stability and permeability coefﬁcients and lower bulk density
values as compared to the soils mixed with ﬂy ash. Sewage sludge added with a rate of 30%
eliminated the negative effects of freeze–thaw processes on wet aggregate stability.
Freeze–thaw processes did not affect the bulk density of the soils II and III, which were
mixed with sewage sludge. However, ﬂy ash addition decreased the bulk density of these
soils very signiﬁcantly after nine freeze–thaw cycles. Addition of sewage sludge or ﬂy ash
with rates of 20% and 30% signiﬁcantly increased the permeability coefﬁcients in soil I after
nine freeze–thaw cycles. Results indicated that addition of sewage sludge and/or ﬂy ash to
saline–sodic soils could be alternative way for reducing negative effects of freezing–
thawing on soil wet aggregate stability, bulk density, and permeability coefﬁcient.
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