[Phosphorus sorption and desorption of agricultural soils under different land uses]

The potential of P loss from soils under different land uses in Taihu Lake watershed was evaluated by laboratory experiment. It was shown that although the P sorption capacity of paddy soils under oxidized conditions were little lower than that of dryland soils the risks of P loss from the former via runoff and leaching were lower than that from the latter, because the soil P levels of the former were much lower than that of the latter. For most paddy soils the P sorption capacity increased and the P release decreased under reduced conditions than that under oxidized conditions and this was attributed to the formation of amorphous Fe2+ hydroxides which have a greater surface area and more P sorption sites than well-crystallized Fe3+ oxides.