Estimation of Water Potential Components of Saline Soils of Great Basin Rangelands

Abstract

AbstractA rapid method is described to assess the solute and matric components of the total soil water potential at field water contents of a saline soil in central Nevada. The solute potential is estimated from saturated paste conductivity (ECp) measurements easily made on the conductivity cell of an instant salinity meter and assumes that the salt concentration varies inversely with water content. The method requires determination of the relationship between ECp and the electrical conductivity of the saturated paste extract, ECe. The total water potential is measured with a Peltier psychrometer. Subtraction of the solute potential from the total water potential results in an estimate of matric potential. Matric potentials estimated in this way were similar to those determined by a pressure plate at volumetric water contents greater than 0.09 m3 m−3 soil and soil ECe's < 15 dSm−1. The method tends to underestimate solute potentials and overestimate matric potentials of soil with lower soil water contents and higher salinity. These measurements are useful in determining plant adaptability on saline, semiarid rangeland soils.