The adoption of management systems that may offer an increase in the organic matter level or of a fraction of it (organic acids, for instance) can contribute to reduce the P adsorption on the surface of the iron and aluminum oxides. The present work aimed to evaluate the interactive effects between acid citric doses plus enzymatic activator and the availability of some phosphorus forms in a soil of strong clay texture and in a medium texture soil, submitted to the application of superficial and incorporated liming. Two types of soil were utilized: Distroferric Red Latosol, with strong clay texture, and loam Distrophic Red Latosol. We conclude that the effect of levels of soil bioactivator in the Pi and Pt contents is less expressive in Distroferric Red Latosol, mainly when the calcareous was incorporated to the soil; while in loam Red Distrophic Latosol, the bioactivator of the soil was more effective in altering the P buffering capacity of this soil, represented by P-rem, in both forms of calcareous application.
Organic acids; adsorption; phosphate
