Omer Anapali

Decrease in Hydraulic Conductivity of Clay Soils with Salinity-Sodicity Problems due to Freezing and Thawing Effect

Freezing and thawing effects on soil structure are an important dynamic property of a soil. Consecutive freeze-thaw cycles in soil may affect aggregation either positively or negatively. Therefore, pore size distribution, hydraulic conductivity, infiltration rate and vulnerability of soil are also affected by freezing and thawing processes (Lehrsch et al., 1991). Radke & Berry (1998) determined a decrease in bulk density after freezing in soils which have a high value of bulk density at the start. Ice crystals forming within pores during freezing widen the diameter of the pores and thus decrease the bulk density (Kay et al., 1985). Aggregate stability is affected by freezing rate, soil moisture content at the time of freezing, and number of freeze-thaw cycles (Benoit, 1973; Edwards, 1991). Oztas & Fayetorbay (2003) found that aggregate stability generally increased when the number of freezing and thawing cycles increased from 3 to 6, but decreased after that point. Thus, freeze-thaw cycles may have negative or positive effects on soil structure. The determination of effects of freeze-thaw cycles in saline-sodic soils on the hydraulic conductivity is of importance for soil management and reclamation. Therefore, this study investigated the effect of freeze-thaw cycles on the hydraulic conductivity in soils. Materials and methods