Infiltration into Freezing and Thawing Soils under Differing Field Treatments

Infiltration characteristics of seasonally frozen soil influence agricultural management and hydrology in many areas. In northern and northwestern China, winter and spring irrigation is conducted during periods with frozen soil when water is available. The shortage of water resources is one of the major factors restricting the further development of cropland and pasture land in this region. Therefore, heightening irrigation efficiency and determining irrigation parameters has become a high priority for agricultural management. A series of field experiments was conducted from November through March in the middle of Taiyuan Basin, Shanxi Province, China, to develop predictive equations of frozen soil infiltration for differing field treatments and varying water contents. Infiltration measurements were made on three field treatments: green bean standing stubble, winter wheat, and deep ploughing. Cumulative infiltration was greatest on the deep ploughing treatment, which had the lowest soil bulk density as compared with other treatments. A strong inverse power function (R2 > 0.90) was demonstrated between water infiltration and water content during the freezing period, and the coefficients for this power function were related to frost depth. The resulting estimates of cumulative infiltration resulted in a coefficient of determination of 0.905. Double frozen layers due to surface diurnal freeze/thaw cycles during soil thawing provided an impediment to infiltration. This study provides a practical basis for determining infiltration parameters for irrigation and water resource management.