Variation of water and salinity in sodic saline soil during frozen-thawing season

By the in-situ observation and analysis in the laboratory,the variation of water and salinity in micro scale(a 32 m-long transect) of sodic saline soil region are discussed during the frozen-thawing season.Results show that vast groundwater is transported and stored in the frozen layer of saline meadow soil in frozen period,which results in the significant enriched soil moisture,the moisture at 30-40 cm layer increases most obviously(increase from 20% before frozen to 50%),and the groundwater level descends abruptly from 1.2 m to 2.5 m below.The enrichment of soil moisture in sodic saline soil isn’t significant; nevertheless,salinity is enriched significantly,the enrichment degree in white crust sodic alkaline soil reaches 80%.The variation of salinity is mainly composed of the increased content of bicarbonate,carbonate,sulfate and sodium.The vastsalinity accumulat ion in surface layer results in the graduall aggravated saline degree during thawing season.