EC (electrical conductivity) is associated with fertilizer concentration, which contributes toward plant growth. Soil is composed of solid components, pore water, and air. Bulk EC is the EC (electrical conductivity) measured from these three components. It is used to measure the EC of a solution. Soil pore water EC is the EC (electrical conductivity) of only the pore water in soil. It can be used to measure fertilizer directly, which contributes to plant growth in soil.