PHOSPHORUS SORPTION IN SOME SOILS OF THE SEMIARID REGION OF THE BRAZILIAN NORTHEAST

This work was carried out in fifteen soil samples of the semi-arid reg ion of the Brazilian Northeast. The soils were the following: five Ver tisols (V), three Red Yellow Latosols (LVa), two Red Yellow Podzolic ( PVa), one Carbonatic Cambisol (CbCarb.), one eutrophic Red Dark Latoso l (LVEe), one Vertic Cambisol (CbV), one Latossolic Cambisol (CbL), an d one non Calcic Brown (BnCa). The objective was to evaluate, through the Langmuir isotherm, the capacity of phosphorus sorption by these so ils. The results obtained showed that the phosphorus sorption by the s oils varied from 0.124 to 0.805 mg P/g. It was higher in the alkaline soils (V, CbCarb, CbV, and CbL) and lower in the acid soils (LVa and P Va). The maximum phosphorus sorption correlated positively with pH, wa ter content at 0.3 bar, CTC, organic matter, clay content and exchange able calcium and magnesium.