Outflow of phosphorus on rice seeds or seedlings (Oriza sativa L., Batatais). (Preliminary results) The purpose of this investigations was to detect the outflow of phosphorus by rice seeds or seedlings. Two experiments were conducted as following: a) Firts experiment Rice seeds were soaked in water solution containing P32 during 12 hours. After that period the solution was descarded and the seeds washed in a solution of P32. Aliquots from that solution were taken and exposed to a Geiger counter. The seeds were washed until no counts in the solution were detected by the counter. The seed were sowed in crystallizing dishes which contained 200 grams of quartz or 100 grams of quartz mixed with 100 grams of soils. The Neubauer tecnique was employed. The plants were harvested 18 days after the germination. Substrate (soil, quartz) and plant extracted were performed and the activity was measured. Activities were detected in all semples, what prove the outflow of P32 from the seeds or the plants. The outflow of P32 from the plants in show in the follonwing table. Treatments % P32 outflowed and not absorbed quartz 9.60 quartz + savanna soil 32.4 quartz + "terra roxa" 46.2 b) Second experiment Radioactive seeds were obtained by providing a solution containing P32 to rice plants growed in pots. A modification of the Neubauer method was used, as it is described by CATANI & GERBAMIN (1961). The treatments were: quartz, quartz + "arenito de Bauru", quartz + "terra roxa", quartz + "massapé-salmcurão". The experimental techniques were same as in the first experiment. In the same way the outflow was proved, as it can be seen on the following table. Treatments % Pn outflowed and not dbsorved quartz 12.5 quartz + "arenito de Bauru" 13.6 quartz + "terra roxa" 20.7 quartz + "massapé-salmourão" 14.4 The results sugested that there is an outflow of phosphorus from the rice seeds or seedings.