Soils Home | Subset Home

Classification, Properties, and Management of Aridisols

Saline Soils

Aridisols Slide 73

Availability of water is not the only constraint on the use of Aridisols for agriculture. Soil horizons produced by arid climatic conditions also affect the use of these soils. Soil management must address these problem areas.

Aridisols Slide 74

One of the most extensive problems facing irrigated agriculture in arid regions is the presence of soluble salts in the soil in amounts which inhibit plant growth. This aerial photograph shows salt accumulation in fields and its effect on crop growth. Approximately one-third of developed agricultural lands in arid regions reflect some degree of salt accumulation.

Aridisols Slide 75

Salt affected soils are commonly classified for management purposes into three groups; saline, sodic, and saline-sodic. Two criteria are used for this classification, the electrical conductivity of the soil saturation extract (EC) and the exchangeable sodium percentage (ESP). Electrical conductivity is directly related to soluble salt concentration in soils. The exchangeable sodium percentage is a measure of the amount of sodium on soil exchange sites.

Aridisols Slide 76

Saline soils often have a surface salt crust as seen here. Only very salt tolerant plants can grow in such soils. As soil salinity increases, soil water becomes less available to plants because of higher osmotic pressures, even if soil moisture is plentiful.

Aridisols Slide 77

Plants vary widely in their tolerance to salts. This graph correlates decreases in crop yields with salinity levels. Notice how barley and sugar beets are much more tolerant of high soil salinity levels than are cowpeas and beans. Today, plant scientists continue to breed crop varieties that are increasingly tolerant to soluble salts.

Aridisols Slide 78

Saline soils can be reclaimed for agricultural use by leaching. Leaching involves applying large volumes of water to the soil to move soluble salts out of the rooting zone. To be effective, internal soil drainage must be adequate so salts will not rise again into the rooting zone.

Aridisols Slide 79

Seed placement is also important in the management of saline soils. Under furrow irrigation soluble salts are concentrated toward the crest of the bed. Therefore, optimum seed placement is on the lower side of the bed, as seen here.

Introduction to Aridic Soils | Soil Taxonomy | Introduction to Soil Horizons | The Horizons | Suborders and Great Groups | Argid Suborder | Orthid Suborder | Subgroups | Families | Non-Aridisols | Irrigation | Saline Soils | Sodic and Saline-Sodic Soils | Final Considerations

URL:http://cals.arizona.edu/OALS/soils/aridsoils/saline.html
Last revised: 29 August 2001
Site created and maintained by the Office of Arid Lands Studies