SAR stands for sodium adsorption ratio, a critical metric used by agronomists to evaluate the suitability of irrigation water and the structural stability of soil. It quantifies the ratio of sodium ions to calcium and magnesium ions in a soil extract or water sample. A high SAR indicates that sodium will replace calcium and magnesium on the soil exchange complex, which causes clay particles to disperse, ruins soil structure, and severely restricts water infiltration.
The lab results show the well water has an SAR of 14, so we need to apply gypsum before it seals off the clay completely.
Related terms
Sodium adsorption ratio
A water quality metric that indicates the potential for sodium to build up in soil.
Soil fertility
The capacity of soil to provide essential nutrients and a suitable environment for plant growth.
Topsoil
The uppermost layer of earth, rich in organic matter and biological activity.