我国滨海酸性硫酸盐土壤中几种不同形态的酸

SOME ACID FORMS IN ACID SULFATE SOILS IN COASTAL REGION OF CHINA

本研究结果表明,我国滨海酸性硫酸盐土壤中含有大量的黄铁矿,它是一种潜在性酸,氧化后产生硫酸,是这种土壤的主要致酸原因。酸性硫酸盐土壤的pH值很低,一般在3.2至5.5,交换性酸和水解性酸的量很大,一般在0.2至10.5cmol/kg和5.0至31.0cmol/kg。几种形态的酸处于动态平衡,相互制约。随酸性硫酸盐土的剖面发育,黄铁矿的最高含量层、pH值最低层、以及交换性酸和水解性酸的最高含量层都不断向下移动。

There are about 67000ha of acid sulfate soils in China. They are mainly distributed in the coastal region of the southern part of China. This study deals with the amount of some acid forms in acid sulfate soils and their interrelations. Acid sulfate soils contain a large amount of pyrite, Which is a kind of potential acid form and can produce active acidity after its oxidation, The soils contain a large amount of exchange and hydrolytic acidity, generally 0.2—10.5cmol/kg, and have a very low pH value, generally between 3.2 and 5.5. Pyrite (FeS_2) is a determinant form of acidity in the soil, but the different forms of acidity are related each other in a equilibrium system.The amount of pyrite, exchange and hydrolytic acidity decrease with the development of the soils, and the most acid layer goes downwards in the profile.