Soil Salinity Surveying and Mapping
Elia Scudiero1,2, Todd H. Skaggs2, & Dennis L. Corwin2 1UC Riverside, Environmental Sciences Dept. & 2USDA-ARS, U.S. Salinity Laboratory, Riverside, CA
SOIL CAN CONDUCT ELECTRICITY
Soil apparent electrical conductivity (ECa)
Text
Using ECa to estimate soil salinity
Soil Salinity
ECa not a direct measurement of any single soil property
Electrical resistivity Electromagnetic induction
TEMPORAL SALINITY CHANGES
Two- or three-dimensional changes
in salinity can be monitored when
surveys are repeated over time.
• 2002-2011 soil salinity changes
with a cross-section view
• ECe change = ECe(2002) – ECe(2011)
• Presence of soluble & readily dissolvable salts
(Na+, Mg2+, Ca2+, K+, Cl-, SO42-, HCO3
-, NO3-, CO3
2-) in the soil
• Usually measured as electrical conductivity of saturated
soil extract (ECe, dS/m)
• ECe is commonly used as an expression of the total
dissolved salt concentration of the saturated soil
extract
TDS(mg/L) = ~640× ECe (dS/m)
Soil Salinity in orchards
FIELD-SCALE SALINITY MAPPING
ECa sensors measurements can be calibrated to soil salinity (ECe)
using collocated soil laboratory measurements and linear modeling
Sprinklers and flood irrigation
• Uniform vertical leaching of salts
• Accumulate at the bottom of the
root-zone
Micro irrigation
• Salts are leached away from
the wetting source
• Mainly accumulate at the
fringe of the wetted zone
- Salinity (ECe) ↑
- Texture (Sand ↓; Clay ↑)
- Water Content ↑
- Gravel (↓)
Elia Scudiero, Ph.D. | Assistant Research Agronomist | 450 W. Big Springs Rd., Riverside, CA, 92507 | +1 951 369 4847 | [email protected]
