酸化对黄壤及石灰土腐殖酸提取效果的影响

Effects of Acidifying Yellow Earth and Limestone Soil on the Extraction of Humic Acids

为提高不同类型土壤腐殖酸的提取率,探讨黄壤和石灰土腐殖酸提取流程中是否需要酸化,对黄壤和石灰土酸化后提取的腐殖酸与未酸化直接提取的腐殖酸进行对比。结果表明:黄壤酸化处理既没有明显改变其腐殖酸的提取量,也未改变其腐殖酸的性质;而石灰土酸化处理既提高其腐殖酸的提取量,也改变其腐殖酸的性质。从黄壤中提取腐殖酸不需要经过酸化处理,而从石灰土中提取腐殖酸需要进行预先酸化,以破坏碳酸钙沉淀或腐殖酸钙对腐殖酸的保护,提高腐殖酸的提取效率。

In order to enhance extraction rate of humic acids（HA）from various soil types,and to explore whether it is necessary to acidify yellow earth and limestone soil during the extraction process,The authors compared the HA extracted from yellow earth and limestone soil and that extracted from the acidified counterparts.Results：There is no need to acidify the soil in advance because there is no effect on the extraction amount and properties of HA by acidifying the yellow earth.On the contrary,it is necessary to acidify the limestone soil for extracting HA because acidifying the limestone soil could raise the extraction rate and change the characteristic of HA.In limestone soil,HA were enveloped by CaCO3 precipitation or reacting with Ca2＋to form the calcium humate could be responsible for these results.