Soil salinity is the build-up of mineral salts on the soil
surface. In Alberta, salts occur naturally in many bedrock deposits and in some
deposits that lie on top of the bedrock. Groundwater flowing through these
deposits dissolves and transports the salts.
Under certain conditions, this groundwater rises to the
soil surface where the water evaporates and leaves the salts behind. Over time,
salts accumulate in these discharge areas (saline seeps) and in high enough
concentrations can prevent plant roots from taking up water and essential
nutrients. This restricts plant growth and reduces crop yields.
Dryland salinity is considered to be a significant soil
degradation problem on the Canadian Prairies. In Alberta, approximately 650,000 hectares of dryland are affected by salinity, causing an average crop
yield reduction of 25 percent in affected areas. The extent and severity of the
dryland salinity problem is increasing in some areas, and is particularly
evident after a series of wet years.
Salinization of irrigated lands, especially in areas of
solonetzic and saline soils, can also be a problem. The risk of salinization
should be considered when planning irrigation programs.
Department of the Environment. State of the Environment Report, Terrestrial Ecosystems. Edmonton: n.p., 2001. With permission from Alberta Environment.