成都某地稻田水—土界面上铁形态的时空分布特征

Spatial and Temporal Distribution of Iron Species at Soil-water Interface of Rice Paddy Field in Chengdu

以盐酸为介质,采用Tessier连续提取法及火焰原子吸收法,分析不同时空条件下成都某地稻田水-土界面上土壤铁形态、总Fe的质量分数及表面水、孔隙水中可溶态铁的质量浓度。结果表明,各形态铁质量浓度随不同时间、土质、灌溉条件的变化而不同;孔隙水溶态铁的质量浓度高于表面水中的质量浓度。通过2块稻田的对比,发现在第1个月的厌氧环境下,水溶态铁质量浓度明显升高,其后基本保持不变。2块稻田总铁的质量分数无明显差异,残渣态铁和有机态铁占总铁的绝大部分,在厌氧环境下残渣态铁会大量的向其他形态铁转化。

A Tessier sequential extraction procedure was used for the fractionation of Fe species in soils at water-soil interface of rice paddy in Chengdu. Under different spatial and temporal conditions, total Fe and Fe species in soils, dissolved Fe in surface water and porewater, were determined by FAAS with hydrochloric acid as media. The results showed that, Fe species varied with water flood- ing time, soil property and irrigation conditions. The mass concentration of Fe-Exc was more in wa- ter-soil interface than in surface water. Contrast tow paddies, when anaerobic surrounding of the first month, Fe-Exc content was significantly higher, thereafter essentially unchanged. The mass fraction of Fe-Tot in both paddies was no significant difference and unchanged. The vast majority of Fe-Tot were Fe-Res and Fe-Om, while in anaerobic surrounding, Fe Res transform to others.