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Soil EC
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| What it is? |
to transmit (conduct) an electrical current and is commonly expressed in
units of milliSiemens per meter (mS/m). Soil EC measurements may also be
reported in units of deciSiemens per meter (dS/m), which is equal to the
reading in mS/m divided by 100.
Soil electrical conductivity (EC) is a measurement that correlates with soil properties that affect crop productivity, including soil texture, cation exchange capacity (CEC), drainage conditions, organic matter level, salinity, and subsoil characteristics. |
| Relevance in crop production |
The conduction of electricity in soil takes place through the
moisture-filled pores that occur between individual soil particles.
Therefore, the EC of soil is determined by the following soil properties PorosityThe greater soil porosity, the more easily electricity is conducted. Soil with high clay content has higher porosity than sandier soil. Compaction normally increases soil EC. Water contentDry soil is much lower in conductivity than moist soil. Salinity levelIncreasing concentration of electrolytes (salts) in soil water will dramatically increase soil EC. The salinity level in most Corn Belt soils is very low. Cation exchange capacity (CEC)Mineral soil containing high levels of organic matter (humus) and/or 2:1 clay minerals such as montmorillonite, illite, or vermiculite have a much higher ability to retain positively charged ions (such as Ca, Mg, K, Na, NH4, or H) than soil lacking these constituents. The presence of these ions in the moisture-filled soil pores will enhance soil EC in the same way that salinity does. TemperatureAs temperature decreases toward the freezing point of water, soil EC decreases slightly. Below freezing, soil pores become increasingly insulated from each other and overall soil EC declines rapidly. |
| Management considerations | |
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References
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http://en.wikipedia.org/wiki/Soil_pH dated 4/4/2013 |