Experimental study on effect of corn residue management on soil water content during freezing-thawing period

In order to study the influences of corn residue management on soil water content during freezing-thawing period, water transfer experiment was conducted in a freezing-thawing period under four surface treatments of bare land, corn residue mulching lands with the thickness of 5, 10 and 15 cm. The results showed that the corn residue cover altered the soils frozen states. The land mulched by 15cm thickness straw did not freeze; the initial frozen time of the lands mulched by 5 and 10cm thickness straw were 16d and 25d later than that of bare land, and the frozen depths of the lands decreased by 29cm and 42cm than that of the bare land. Affected by the processes of freezing and thawing, the higher moisture content area occurred at 40cm depth in the bare land and occurred at top soil and 30-50cm depth in the straw mulch lands. During the freezing-thawing period the water content fluctuation of 5, 10 and 15 cm straw mulched lands were lower than bare land by 1.12、6.46 and 8.7 percent respectively, and the average water content at 0-10cm soil of the straw mulched lands were higher than that of bare land by 9.45、9.04 and 8.99 percent respectively when soil thawed entirely. The results will provide a basis for taking measure of corn residue cover in seasonal freezing-thawing regions.