The Effect of Protozoa Movement on Soil P Translocation and Transformation

Three common soil protozoa （Bodo edax, Colpoda cucullus, and Amoeba proteus） and Colpoda cucullus, isolated from soil, were used in the research. Two- room incubation （nilong net seclusion）, soil column and root box incubation experiments were carried out to study the phosphorus translocation companying to the protozoa movement in different soil bulk density, soil moisture and food resource conditions. The effects of protozoa on maize growth and phosphorite powder availability were also involved: translocation and transformation of protozoa on phosphorus in soil in different phosphorus level, the absorptivity of maize on phosphorus nutrient affected by protozoa inoculation; and the effect of protozoa on phosphorite powder solubilization. The results showed that protozoa movement were greatly controlled by the net diameter. Bodo edax（about 5⁷μm）, Colpoda cucullus （30⁶0μm）, and Amoeba proteus （100¹50μm） could pass through the nilong net in diameter of 5²00μm.. Colpoda cucullu were the most kind in the number among the common species. Result showed that most protozoa could pass through the net pores of 30μm ,50μm and 800μm diameters.. All of the protozoa tested in the experiment could redistribute ³²P within soil column. In this process, soil bulk density, soil moisture and microbial food resources could affecte the protozoa movement and ³²P redistribution. It was found that the added phosphorus was translocated into maize rhizosphere by the Colpoda cucullus, which significantly improved maize growth. The presense of Colpoda cucullus also improved phosphorite powder solubilization significantly, especially in the treatment of inoculation with soil microorganisms and protozoa simultaneity.