Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2000
Publication Date: N/A
Technical Abstract: Recharge of soil moisture is often cited as an important benefit of snow, but quantitative data are scarce. Year-round precipitation and soil moisture have been continuously measured for a number of years at the University of Minnesota's Rosemount Agricultural Experiment Station, and we have examined this data set to determine the efficiency with which snow is converted into soil moisture. The answer to this question depends upon where you look. The diminished hydraulic conductivity of frozen soil impedes infiltration and focuses snowmelt in most years, creating ponds in low-lying areas of each field to a much greater extent than summer rainfall. Consequently, in upland areas of fields, soil moisture shows little change from fall to the following spring. In the low-lying areas where the ponded snowmelt collects, soil moisture does increase from fall to spring, but these areas are generally wetter to begin with, so much of the melted snow drains through the profile. We conclude that from the standpoint of providing water for subsequent crop use, the recharge efficiency of winter snowfall is much lower than that of rainfall in other seasons, although some tillage and residue management options may improve overall recharge efficiency of snow by retarding runoff and ponding during spring melt.