Effects of Soil Gleyization on Phosphorus Fractions and Supply in Paddy Soils

The effects of soil gleyization on fractions and supply of phosphorus in several paddy soil profiles in Sihu Region, Jianghan Plain, are studied with fractionation of soil inorganic phosphorus (Zhang Shoujing-Jakson method). The result shows that there is significant effect of soil gleyization on fractions and availability of phosphorus except for total phosphorus content. As soil gleyization is more developed, the proportions of O-P in inorganic phosphorus and organic in total increase, but the content of available phosphorus decrease. And this effect is related to organic matter and oxidation and reduction condition in the soils.