Abstract

BELTRAN, R.R.; SILVEIRA, R.I.  and  PASSOS, M.J.. DISPONIBILIDADE DE FÓSFORO PARA PLANTAS DE ARROZ AVALIADA POR EXTRATORES QUÍMICOS. Sci. agric. [online]. 1998, vol.55, n.2, pp. 233-241. ISSN 0103-9016.  http://dx.doi.org/10.1590/S0103-90161998000200011.

Phosphorous avaliability to rice plants was evaluated in an experiment under greenhouse conditions using an acid and low phosphorus soil. Five fertilizers (Alvorada rock phosphate-FNA, amonion monophosphate-MAP, simple superphosphate-SFS, triple superphosphate-SFT and magnesium termophosphate-TM), three rates (100, 200 and 300 mg P dm^-3 of soil), one control and ten plants of rice/pot were used. Phosphorus in soil samples were analized using the following extractants: Mehlich-1, Olsen and resin. Dry matter, P content and P absorved by the shoot were correlated with the P recovered by the three chemical methods. The MAP and SFS at the rate of 200 mg P dm^-3 of soil, allowed the highest dry matter accumulation in above ground parts of rice plants. The MAP and SFS at the rate of 200 mg P dm^-3 of soil, allowed the highest dry matter in above ground parts of rice plants. Differences among soil chemical P-extractants and a positive correlation with the evaluated parameter were observed. Olsen's extractants showed were the best correlation with rice response to rates and sources of P.

Keywords : fertilization; phosphorus; soil analysis; Oriza sativa; extractants .