The satisfactory results obtained in monitoring soil salinity and ion concentration, by means of porous ceramic cup extractors, motivated the realization of this study, which objective was obtaining calibration curves for these extractors to monitor soil electrical conductivity and concentration of nitrate and potassium in two different soils. The nitrate concentrations tested were the same for the two soils (0; 84; 168; 252; 336; 420 and 504 mg L-1) but, for potassium, different concentrations were used for sandy soil (0; 117; 234; 351; 468; 585 and 702 mg L-1) and clay soil (0; 117; 234; 351; 468; 585; 702; 1,170; 1,755; 2,340; 2,925 and 3,510 mg L-1). Electrical conductivity of soil solution and concentrations of nitrate and potassium were estimated with satisfactory precision from soil solution collected with porous ceramic cup extractors, but this task must be preceded by a calibration for each soil type.
soil solution; electrical conductivity; potassium; nitrogen
