Publication - Management of saline soils under irrigation
Titre en anglais
Management of saline soils under irrigation
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Sommaire en anglais
Management of saline soils is a complex, continuing problem in the irrigation districts of Canada. Because many factors are involved, the problems associated with a particular site are usually site-specific. However, there are general principles that apply to soil salinity as a whole. Each year more is learned about the management of saline lands, but the need for new, more effective solutions to the salinity problems in agriculture continues. Soil salinity occurs mainly in waterlogged, poorly drained soils. Saline and saline-sonic soils, which occur in nonirrrigated and irrigated land, contain enough water-soluble salts to affect crop growth. In Alberta, Saskachewan, and Manitoba, more than 80 000 ha of irrigated lands and 2.5 million ha of nonirrigated lands are saline or saline-sonic. In the irrigation districts, the main causes of salinization and waterlogged of the land are seepage from canals, poor water management, poor irrigation practices, and adequate drainage. Under nonirrigated farming, the main causes are the introduction of cereal crops in the place of native range, summerfallowing of cereal cropland, and obstacles of human origin that trap snow and water and impede drainage. To alleviate problems, excess water must be prevented from entering the land, or the excess water from the affected area must be removed through drainage, followed by leaching to remove the salts and cultural practices that are compatible with the local conditions. The area of land under irrigation is a small portion of the arable land in the prairies, but its production is high. For instance in Alberta about 4 percent of the arable land is under irrigation, but it produced about 20 percent of the agricultural products. This publication is concerned mainly with salinity problems or irrigated land because it is so important. However, many of the principles apply to nonirrigated land.