Using Electrical Conductivity (EC) Sensors in Precision Agriculture
The measurement of soil EC is widely used in agriculture. However, there is still confusion around the meaning of the readings and their application in precision agriculture.
To what extent can EC sensors be used for ‘precision fertilization management’? In fact, ‘Soil EC’ may refer to different types, or methods, of EC readings, each with its own significance.This article will explore the meaning of the different EC measurements and evaluate their applicability for precision agriculture.
The electrical conductivity is the ability of a material to transmit electrical current. The question is, therefore, which medium is being measured and how can the reading be interpreted and used? The most commonly used EC measurement in precision agriculture is the soil bulk EC, or soil apparent EC (ECa). This soil EC correlates with various soil properties, such as soil texture and water holding capacity. Sandy soils will have a lower EC reading than clay soils.
Mapping the ECa within a field provides additional information on the soil variability within that field and on year-to-year trends, such as salinization and compaction of the soil. Such information can aid in deciding on variable rates of herbicides and nitrogen fertilizer, as their application efficiency depend on soil texture. For instance, a split application of nitrogen may be required in light-textured soils.