冻融季节苏打盐渍土的水盐变化规律

通过野外定位观测和室内分析,探讨了冻融季节的微域尺度(32 m长的横剖面)苏打盐渍土的水分和盐分的变化规律.结果表明:冻结期大量地下水迁移并储存在盐化草甸土的冻层中,同时地下水位埋深迅速从1.2 m下降到2.5 m以下;苏打盐化草甸土冻结层的含水率明显增加,其中30~40 cm土层的含水率变化最明显(从冻结前的20%增加到50%).苏打碱土冻层的含水率增量不明显,但盐分显著增加,其中白盖苏打碱土表层的盐分增量幅度达80%.盐分变化主要表现为苏打盐渍土表层HCO₃-、CO₃2-、SO₄2-以及Na+的增加,大量盐分表聚使消融期土壤的盐渍化程度不断加重.

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.