模拟酸雨对土壤性质的影响

利用模拟系统研究了酸雨对四川有代表性的土壤的 pH、交换性能、化学组成和微结构的影响。结果发现,石灰性红棕紫泥抗酸雨能力最强,盐基饱和度低的酸性与中性土壤对酸雨最为敏感,pH>4的弱酸雨对这类土壤 pH 和盐基总量没有显著影响,而 pH<4的强酸雨则使其酸碱度(pH)骤然下降。土壤的盐基饱和度和 pH 之间呈直线关系。在强酸雨作用下,土壤的交接性氢、铝增加,重金属铜易被酸雨所淋洗,铅、锰则不易被淋溶而富集在土壤中。酸雨对石灰性土壤的微结构也许有好的作用,能使粘质土微结构遭受大的破坏而对砂质土的微结构影响不大。

RESEARCH ON EFFECTS OF ACID PRECIPITATION ON SOIL PROPERTIES

The effects of acid precipitation on soil pH,exchange capacity,soilcomposition and soil microstructure of typical types of soils in SichuanProvince were investigated on using a model system.It has been foundthat caleareous soil,red-brown-purple soil,has a big antiacidrainfallcapability even though calcium and potassium of the soil are leachcd byacidrainfall at a great extent.The soils which have a low base-saturationpercentage,red-purple soil are highly sensitive to the acid precipitation.Soil pH and base content are slightly influenced by weak acidrainfall(ph>4)and decreased rapidly when strong acidrainfall(pH<4)is used.The relationship curves or the bas saturation percentages of soil and pHare straight lines.Under the effects of the acid precipitation exchangeablehydrogen and exchangeable alluminium increase.Among heavy metals,cuprum is easy to be leached and lead and manganese would be concentratedin soil because they are not easy to be teached.Acid precipitation mayhave a good effect on microstructure of silt caleareous soil and makes agreat change in microstructure of clayey soil and a small change inmicrostructure of sandy soil.