CERAMIC CUP EXTRACTORS AND DILUTE SOLUTIONS FOR SOIL SALINITY DETERMINATION

Abstract

The objective of this work was to evaluate the possibility of using porous ceramic cupextractors and the dilute solution technique 1:2 (distilled dry soil:water) to quantify the soilsalinity, correlating the electrical conductivity (EC) values obtained by these methods with thestandard method (saturation paste extract). An experiment in laboratory was carried out usingsoil conditioned in pots irrigated with water concentrations of 1.0; 2.5; 4.0 and 5.5 dS.m -1 andleaching fractions of 10% and 30% of evapotranspiration , resulting in different levels of soilsalinization. Electrical conductivity was measured in the saturation extract (ECe), in 1:2 solution(EC1:2) and in soil solution collected through porous cups at soil moisture level near to the fieldcapacity of the soil contained in the pots (ECscp). The values of ECscp overestimated 19.35%of the average ECe measured before the moisture correction. After the correction of thedifferent soil moisture levels, the values obtained with the cups extractors presented a closerelationship (1:1) with the ECe values, with a r 2 =0.93. EC1:corresponded to 15.48% of ECe, before the moisture correction. However, when the electrical conductivity corrections in functionof the moisture levels were accomplished with average values they were 18% higher than ECevalues, possibly due to the solubility of calcium carbonate.