蚯蚓对土壤中有机化学成分组成的影响

Effect of Earthworms on Organic Chemical Components of Soil

蚯蚓是最为重要的土壤动物之一,不仅可以改良土壤结构和肥力,还能促进土壤矿物风化。为研究蚯蚓风化土壤矿物的机理,弄清蚯蚓对土壤中有机化学成分的影响,我们以甲醇为浸提剂浸提蚯蚓处理过的土壤和无蚯蚓的土壤,对提取物硅烷化衍生处理后,用GC-MS进行了分析。结果发现无论是蚯蚓处理过的土壤还是无蚯蚓的土壤,提取物中种类最多的化学物质是烃类,其次是酯类;腈类种类虽非常少,但相对含量却非常高。蚯蚓处理的土壤与无蚯蚓的土壤二者之间有机化学成分确实有很大的不同:从蚯蚓处理过的土壤中共发现了22种特有成分,从无蚓蚓的土壤中共发现了26种特有成分。虽然蚯蚓处理的土壤和无蚯蚓的土壤均检测到了微量的有机酸,但无论是酸的种类还是数量二者间均无明显差异。另外,检测结果也未发现铁载体。因此,蚯蚓诱导的微生物对土壤矿物的风化应该是在土壤矿物局部区域发挥作用,其风化机理用连宾的综合效应假说解释更为合理。

Earthworms are one of the most important groups of soil animals. They not only can improve soil structure and fertility, but also promote the weathering of soil minerals. To investigate the effect of earthworms on organic chemical components of soil and illumi- nate the mechanisms of weathering soil minerals by earthworm, we extracted organic compounds by solvent methanol from the soils trea- ted with earthworms, and then characterized the organic components of soil extracts using GC-MS after silylation derivatization. Results showed that hydrocarbons were the most abundant components among all extract, followed by esters. There were very few kinds of nitrile in the extract, but with high contents. There were 22 exclusive components in the soils treated with earthworms and 26 exclusive compo- nents in control group. Small amounts of organic acids were found in the two kinds of soils, but there were no significant differences in the kinds and contents of the organic acids between the soils treated with earthworms and the control. In addition, none of siderophores were found in all soils. Based on above results, we speculate that the bioweathering of soil minerals, by microorganisms induced by earthworms, occurs on the local region of minerals, and its mechanisms may be explained by Lian＇s the combined effect hypothesis.