潮土两个亚类中含量差异大，潮土亚类含量最高，平均为49.6mg/kg，

The content of the two subgroups of the Chao soil is very different, and the content of the subgroup of the Chao soil is the highest, with an average of 49.6mg/kg, with an amplitude of 12.2~132.7mg/kg, with a large amplitude and uneven content; the content of salinized Chao soil is low , The average is 37.58mg/kg, the variation range is 21.0~50.6mg/kg, the variation range is small, and the content is uniform. Available iron content of each sub-category: Chao soil>Saline Chao soil

The content of the two sub-classes of tidal soil is very different, the highest content of the tidal soil sub-class, the average is 49.6mg/kg, the variation is 12.2 to 132.7mg/kg, the variation is large, the content is not balanced; Effective iron content in sub-types: tidal soil and salted tide soil

There is a big difference between the two subgroups. The content of fluvo aquic soil is the highest, with an average of 49.6mg/kg and a range of 12.2-132.7mg/kg. The content of salinized fluvo aquic soil is relatively low, with an average of 37.58mg/kg and a range of 21.0-50.6mg/kg, with a small range and even content. The effective iron content of each sub group was: fluvo aquic soil > salinized fluvo aquic soil