澧阳平原古水稻土铁形态分布特征研究

为了揭示埋藏古水稻土铁形态分布特征，采用Tessier连续提取法分析测定了澧阳平原古水稻土铁的形态。结果表明澧阳平原古水稻土的铁主要以有机质态铁、氧化物结合态铁和残渣态铁形态存在，占全铁量的99.9%。除有机物结合态铁，其他形态铁平均含量表现为：埋藏古水稻土＞现代耕种水稻土，且古水稻土各形态铁分异明显，水溶态铁、交换态铁、氧化物结合态铁和有机物结合态铁均呈现先增加后减少的趋势，残渣态铁随埋深而增加。澧阳平原古水稻土的铁有明显的淋溶淀积特征，不同形态铁在各土层变异较大。

Distribution characteristics of iron Species in ancient paddy soils of Liyang plain

The study objective is to fully understand the distribution characteristics of iron form in buried ancient paddy soil. The Tessier sequential extraction procedure was used to extract different chemical Fe forms of ancient paddy soil Fe at Sanlonggang village, Liyang plain. The results showed that the main forms were the organic matter bound Fe (OM-Fe), oxides bound Fe (OX-Fe) and residue Fe (RES-Fe), which made up 99.9% of the total iron contents in ancient paddy soils at Sanlonggang village. Besides OM-Fe, the average content of other Fe forms was greater in the ancient paddy soil than that in the current cultivation paddy soil, and the obvious variation of different forms of Fe was observed, and the trend of Fe (WS-Fe), exchangeable Fe (EXCFe), OX-Fe, and OM-Fe first increased, and then decreased, while the trend of RES-Fe increased with soil depth increase. The characteristics of elevation and deposition in ancient paddy soils were obvious, and the distribution variation of different forms of Fe was greater in the ancient paddy soil at Sanlonggang village.