IMPROVED FIELD METHOD FOR ESTIMATING SOIL SALINITY

Soil salinity is a worldwide limitation for agriculture productivity and simplified procedures to assess salinity are needed. In this study, an efficient method for estimating electrical conductivity (EC) on a saturation extract (ECex) from readings in saturated soil-paste to assess soil salinity was improved. EC values measured in a saturation extract (EC ex ) were compared with those estimated from a saturated paste (ECest) in 36 texturally- different samples from a broad array of soils with halophyte and glycophyte vegetation in the semiarid region of Argentina. The EC est values were very close to EC ex values up to 8 dS m-1, at greater values, estimates tended to diverge from observed values. Determination of EC in a saturated soil-paste is a simple and rapid procedure resulting in an accurate estimation of EC in the saturated extract as indicated by the high degree of predictability (r 2 = 0.95; P< 0.01). In addition, the pH measured in the saturated paste was a good predictor of soil pH, and closely approximated the pH determined in a 1:2.5 soil: water mixture. Key word. Field soil salinity, saturated paste.