论季节冻结区盐渍土改良问题

Improvement of Saline Soils in the Seasonally Frozen Ground Regions

Different kinds of crops are different in salt-resistance and different kinds of salts do harm to crops to different extent. It is necessary to have a desalination standard for the improvement of saline soils. Sometimes, the existence of a few salts unharmful to crops can help to restrain the alkalization of soils. During the dayey soil freezing downwards, the salts and moisture would migrate upwards to the active layer. While in Spring, when the soils thawing, the existence of the temporary unthawed layer could hinder the drainage of moisture and salt solution from the upper thawed layer, so that salts would furtherly migrate towards the uppermost layer of the soil profile under the heavy evaporation. This is unfavorable to the sprouting and seedling. It is necessary to have an appropriate measure of drainage and irrigation to restrain the ion migration during soil freezing and the further salination during thawing . Under a certain condition, the drained mineralized water can be repeatedly used for the desalination of soils.