Paddy Soil Flooding On The Chemical Behavior Of Iron In Change On P Availability

Three simulative experiments were carried out to study the transformation of iron oxides and inorganic phosphorus, and their effects on P availability under flooding or alternating flooding and air-dried conditions in a red earth (Ultisol) and a deglyed dark paddy soil (Entisol), which are widely distributed in Zhejiang Province of China. Three kinds of synthetic iron oxides (SIQ) with different crystallinity (i.e. goethite, hematite and ferrihydrite) were used to study the effects of pH and organic anion on phosphorus adsorption-desorption by iron oxides. The results obtained from these experiments are summarized as follows. 1. The chemical behavior of P and Fe in flooded soils and their effects on P availability The content of amorphous Fe oxides (Fe0) of the soils increased significantly with the decreasing of crystalline Fe oxides (Fed) during the flooding process, and they are negatively correlated at P