Abstract: Effects of regulation of pH and application of organic material on adsorption and desorption of phosphorus in red soil,latosol and paddy soil were studied.It was found that both adsorption and desorption of phosphorus in latosol and paddy soil decreased with rising pH,but the phenomenon was not as significant in red soil.Soil cation exchange capacity,contents of organic matter,iron and aluminum oxides were the main factors affecting adsorption and desorption of phosphorus in these soils.Red soil was low in CEC and content of organic matter,and high in content of Fe/Al oxides,leading to higher adsorption of phosphorus in red soil than in other two soils,while latosol and paddy soil were high in CEC and content of organic matter,which formed a high repulsive force on soil surface and an organic matter coating covering P adsorption sites on the surface,respectively,thus making the two soils adsorb less P than red soil did.Incorporation of rice straw and incubation under a given temperature decreased P adsorption significantly in red soil and paddy soil,but the effect was not as significant in latosol.However,incorporation of rice straw increased P desorption and its desorption rate in these soils,thus improving mobility of adsorbed phosphorus therein.

Key words: adsorption-desorption of phosphoru, pH, iron and aluminum oxides, acid soil, organic materials, latosol, red soil, paddy soil