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凡是地势低窪或土壤组织紧密而排水不良的乾旱地区,都有轻重不同的盐碱土。由于地势较低而地下水位较高(农民称为水皮浅,约在五、六尺以上),土壤中或地下水中的盐份就很容易随着土壤水分的蒸发而聚积在地面,又由于雨量较少(少于五、六百公糎),蒸发量大(大于雨量的三、四倍以上),盐份上升到地表的多,而被雨水洗冲到土壤下层的少。因此,在春季乾旱的时候,盐碱地的地表往往铺盖一层白色的盐皮。明瞭了盐碱土的发生原因,对于如何改良盐碱地以及防止返碱(其实是反盐,为了通俗起见,在此仍沿用此名),是有帮助的。譬如说,既是了
Alluvial or desertified soils with poorly-packed or poorly-drained soils have salinities of varying severity. Because of the low ground and high groundwater level (peasants call shallow water, about five or six feet), the salt in the soil or in groundwater can easily accumulate on the ground as the soil moisture evaporates, Less rainfall (less than five or sixty kilometers), large evaporation (more than three or four times the rainfall), the salt rises to the surface more, and was washed into the soil washed less. Therefore, during the spring drought, the surface of the saline-alkali land is often covered with a white salt skin. Understand the causes of the occurrence of saline-alkali soil, for how to improve the saline-alkali soil and to prevent the return of alkali (in fact, anti-salt, for the sake of popularity, where still use the name), is helpful. For example, it is