Soil Electrical Conductivity and Soil Salinity: New Formulations and Calibrations

Abstract

A new model describing the relation between bulk soil electrical conductivity (ECa), volumetric content (θw) and electrical conductivity of soil water (ECw) is given along with supporting evidence for its validity. The new model distinguishes between the water and salt present in the soil in the “immobile” (fine pores) and “mobile” (large pores) phases. It provides a possible physical meaning to the transmission coefficient (T) previously used in an earlier model and eliminates a limitation of that model which existed under conditions of low salinity. New empirical relations are provided to estimate the parameters needed in the new and old models in order to utilize them for diagnosing soil salinity, in terms of the electrical conductivity of the extract of saturated soil pastes (ECe).

Delineation of management zones with soil apparent electrical conductivity to improve nutrient management

“…This high correlation is expected because it reflects the influence of salts on the EC a reading and because these properties are highly correlated (Kaffka et al, 2005). Salts and Na + concentrations increased soil solution conductivity (Rhoades et al, 1989) and is consistent with findings in previous studies (Kaffka et al, 2005).…”

“…These series had higher salt content values (higher EC 1:2.5 ) and clay content than the Canals series. In the model proposed by Rhoades et al (1989), they identified that the major factors that influence EC a are: (I) the electrical conductivity of the soil solution associated with continuous and discontinuous pores; (II) the volumetric content of soil particles; (III) the electrical conductivity of the soil particles and; (IV) the volumetric water content in the soil. The first, second and third factor are influenced and increased by soil salinity (Malicki and Walczak, 1999), clay content (Rhoades and Corwin, 1990), and CEC (Shainberg et al, 1980), respectively.…”

“…The first, second and third factor are influenced and increased by soil salinity (Malicki and Walczak, 1999), clay content (Rhoades and Corwin, 1990), and CEC (Shainberg et al, 1980), respectively. With respect to the fourth factor, the conduction of electricity in soils takes place through moisture-filled pores between soil particles; soils with high clay content generally have more continuous water-filled pores that tend to conduct electricity more easily than sandy soils (Rhoades et al, 1989).…”

“…The geospatial measurement of EC a is an efficient ground-based sensing technology that is helping to take HMZ from concept to reality (Corwin and Lesch, 2003). EC a can be intensively recorded in an easy and inexpensive way, and it is usually related to various physico-chemical properties across a wide range of soils , because it depends on the chemical composition of the soil solution and soil exchangeable ions, clay content, and the interaction between non-exchangeable and exchangeable ions (Rhoades et al, 1989). This methodology can improve the characterization of the spatial pattern of edaphic properties that influence the nutrient content of the soil, which in turn can be used to define SSM units (Moral et al, 2010).…”

Leaching impacts Ni toxicity differently among soils but increases its predictability according to nitrification assay

“…All of the factors determining the leaching factor for both total-Ni-based EC50 and solution-Ni-based EC50 are related to the immediate adsorption capacity of soil and thus the leachability of Ni added as soluble salt to soil. Particularly, EC is an indicator for soil salinity (Rhoades and Corwin 1990;Rhoades et al 1989), and salinity can largely impact the retention of soluble metals added to soil through competitive adsorption and salt effect enhancing the solubility of the added salt. Therefore, in Hulunber soil with highest EC high leachability of dissolved Ni in soil solution may be responsible for the highest leaching factor.…”