不同碳源对水稻土泥浆中铁还原特征的影响

Reductive Characteristics of Paddy Soil Slurry with Different Carbons

以四川省典型水稻土(SC)和浙江省典型水稻土(ZJ)为供试土壤,通过泥浆厌氧培养试验,测定添加葡萄糖、乙酸盐及乳酸等碳源处理下土壤泥浆中Fe(Ⅱ)含量变化,采用Logistic模型对Fe(Ⅲ)的还原特征进行拟合。结果表明,2种水稻土中利用不同碳源的铁还原能力具有明显差异,不同碳源对ZJ的铁还原特征影响较为明显,而对SC的铁还原影响有限;在SC中,添加不同碳源后最大铁还原速率为葡萄糖>乳酸>+Fe>乙酸盐;在ZJ中为葡萄糖>+Fe>乙酸盐>乳酸。通过添加乳酸和乳酸盐处理的比较发现,体系的pH对铁还原的影响显著,其中石灰性水稻土SC酸碱缓冲能力强,表现为对乳酸和乳酸盐处理的铁还原差异不显著,而在酸性水稻土ZJ中的差异明显。葡萄糖对供试土壤中铁还原过程具有明显的促进作用,而添加乙酸盐则具有一定抑制作用,乳酸的作用则因土壤酸碱度而异。较乳酸而言,乳酸盐对水稻土的酸碱性没有选择性,且能够对铁还原过程起到促进作用。

In order to identify the different characteristics of Fe（Ⅲ） reduction in paddy soil cores with different carbon source treatments,we chose two typical paddy soil samples from Sichuan and Zhejiang to incubated in anaerobic culture.We measured Fe（Ⅱ） contents in adding glucose,acetate and lactate,then used Logistic model to analyze Fe（Ⅲ） reduction characteristics.The results showed that iron reduction has a significant difference according to the types of paddy soils and carbon sources.The effects of carbon sources on iron reduction in Zhejiang paddy soil were more significant than those in Sichuan paddy soil.In Sichuan paddy soil,the maximum rate of iron reduction decreased in the order of glucose lactic acid ＋Fe acetate,and glucose ＋Fe acetate lactic acid in Zhejiang paddy soil.With the comparison of lactic acid treatment and lactate treatment,we found the effects of pH on iron reduction were outstanding.That was iron reduction of calcareous Sichuan paddy soil were not significantly different with lactic acid and lactate,so not as acid Zhejiang paddy soil.Glucose stimulated dissimilatory iron reduction most significantly opposite to acetate,and the role of lactic acid varied due to soil pH.Lactate promoted iron reduction that was no bossiness with soil pH compared with lactic acid.