季节性冻融对土壤水分的作用及其在农业生产中的意义

Effect of Seasonal Freezing on Soil Moisture and Its Significance for Agriculture

正冻土体冻结缘的水势梯度导致非冻结土中的水分向冻结土体迁移，使融解后的土壤水分含量显著提高。然而，土壤水分增加的数量决定于冻结前土壤水分的剖面分布状况。根据田间试验结果，利用土壤冻融作用对土壤剖面水分的再分布，储水灌溉时间可以提前至９月下旬至１０月中旬，灌溉定额可以降低至６０ｍ３／亩，甚至４０ｍ３／亩。灌溉后及时地进行地面覆盖保墒措施，可以改善较早灌溉和低定额灌溉条件下在播种期的土壤墒情，显著提高作物的出苗率。

Soil moisture increases due to freezing because of water migration caused by water potential of frozen soil fringe However, increase amount depends on the moisture distribution in the soil profile before freezing According to an experiment conducted in field, in connection with mention above, it is suggested that the time for water-storing irrigation can move up to the last ten-day period of September or the middle of October, the amount of water supplying can reduce to 60 m 3 /mu even to 40 m 3 /mu, and having a soil cover after water-storing irrigation can improve the soil moisture content in spite of earlier irrigation and lower water supplying, increasing crop emergence rate