INTRODUCTION
Soil chemical analysis is the principal tool for soil fertility evaluation. The dose of fertilizer to be applied to the soil is mainly based on the diagnosis of the nutrient availability in the soil. A recent literature review has reported that phosphorous (P) availability prediction has been extensively studied over the last decades (Silva & Raij, 1999). However, it is not well known yet how methods are the most suitable for the evaluation of phosphorous availability in waterlogged soils.
Evaluation methods of P availability for rice in drained soils have been tested for flooded rice in lowland soils. Among them, Mehlich 1 is the most available method for Minas Gerais State even if anion exchange resin (resin) is considered more promising in evaluating P availability in flooded rice fields (Grande et al., 1986; Motta et al., 1994).
According to Motta et al. (1994) the P extraction from waterlogged soils by resin was less influenced by variations in organic matter contents and soil texture than by acid extractors. Grande et al. (1986) verified a high correlation between P taken up by flooded rice plants and amount of the nutrient extracted by resin, and a good correlation between Melhich 1 and P uptake by plants only in soils with less than 10% of organic matter.