Soil infiltration characteristics and pore distribution under freezing–thawing conditions

Abstract. Frozen soil infiltration widely occurs in hydrological processes such as seasonal freezing and thawing, snowmelt infiltration, runoff. Accurate measurement simulation of parameters related to frozen are highly important for agricultural water management, environmental issues, engineering problems cold regions. Temperature changes cause pore size distribution variations consequently dynamic capacity during different freeze–thaw periods. To better understand these complex reveal the action effects on capacity, black soils, meadow chernozem were selected test subjects. These types account largest arable land area Heilongjiang Province, China. Laboratory tests soils at temperatures conducted using a tension infiltrometer ethylene glycol aqueous solution. The stable rate hydraulic conductivity measured, was calculated. results indicated that types, macropores, which constituted approximately 0.1 % 0.2 volume under unfrozen conditions, contributed 50 saturated flow, after freezing, macropore proportion decreased 0.05 %, while flow 30 %. Soil moisture froze into ice crystals inside relatively large pores, resulting numerous smaller-sized reduced number macropores but increased mesopores, so no longer solely dependent macropores. After had melted, more pores formed within soil, enhancing permeability.