EFFECTS OF LIME AND ORGANIC MATTER APPLICATION ON SOIL PROPERTIES AND PHOSPHOROS SORPTION BY SIX ACID SOILS UNDER FLOODED CONDITION
Meng Cifu (Institute of Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences) Yuan, T. L. (Department of Soil Science, University of Florida, U. S. A.)
Surface samples of five Ultisols (Dothan,, Red Bay, and Orangeburg from Florida, Manana from Hawaii, and Huangjinni from Zhejiang, China) and one Oxisols ( Wahiawa from Hawaii) were used to ascertain the effects lime and organic matter on P adsorption and desorption under flooded condition. Reagent- grade calcium carbonate and ground dry clover tissues were used as lime and organic matter sources. Both lime and clover tissue addition increased soil pH and decreased Eh, but their effects on pH and Eh of the three Florida soils were less than that on other three soils. Flooding reduced the amounts of Al extracted by 0.5 M CuCl_2. Lime and clover treatments further reduced it for the three Florida Ultisols, but the reverse was true for the other three soils. The amendments reduced the P adsorption for the three Florida soils and the order of reduction followed: clover tissueslimemixture of clover and lime. The effect was reverse for the other three soils. For the three Florida soils, additions of lime and clover tissues increased the P desorption; for the other three soils, the opposite was true. Phosphorus adsorbed by the flooded soils was significantly related with oxalate-extractbale Fe, Al, and Mn and CuCl_2-extractbale Al, which suggests that the components controled P retention by flooded soits include not only pooly crystalline and amorphous Fe oxides and hydroxides, but also Al-OH polymer and Al bound with organic matter.