page_title: Soil salinity control
section_title: Strip cropping: an alternative
hierarchical_section_title: Soil salinity control / Strip cropping: an alternative
caption_attribution_description: English: Principle of strip-cropping and sacrifice of the permanently unirrigated strips to where the soil salinization is directed. Applied at the foot of the Garmsar alluvial fan, Iran
context_page_description: Soil salinity control relates to controlling the problem of soil salinity and reclaiming salinized agricultural land.
  The aim of soil salinity control is to prevent soil degradation by salination and reclaim already salty soils. Soil reclamation is also called soil improvement, rehabilitation, remediation, recuperation, or amelioration.
  The primary man-made cause of salinization is irrigation. River water or groundwater used in irrigation contains salts, which remain behind in the soil after the water has evaporated.
  The primary method of controlling soil salinity is to permit 10-20% of the irrigation water to leach the soil, that will be drained and discharged through an appropriate drainage system. The salt concentration of the drainage water is normally 5 to 10 times higher than that of the irrigation water, thus salt export matches salt import and it will not accumulate.
context_section_description: In irrigated lands with scarce water resources suffering from drainage (high water table) and soil salinity problems, strip cropping is sometimes practiced with strips of land where every other strip is irrigated while the strips in between are left permanently fallow.
  Owing to the water application in the irrigated strips they have a higher watertable which induces flow of groundwater to the unirrigated strips. This flow functions as subsurface drainage for the irrigated strips, whereby the water table is maintained at a not-too-shallow depth, leaching of the soil is possible, and the soil salinity can be controlled at an acceptably low level.
  In the unirrigated (sacrificial) strips the soil is dry and the groundwater comes up by capillary rise and evaporates leaving the salts behind, so that here the soil salinizes. Nevertheless, they can have some use for livestock, sowing salinity resistant grasses or weeds. Moreover, useful salt resistant trees can be planted like Casuarina, Eucalyptus or Atriplex, keeping in mind that the trees have deep rooting systems and the salinity of the wet subsoil is less than of the topsoil. In these ways wind erosion can be controlled. The unirrigated strips can also be used for salt harvesting.
caption: Hydrological principles of strip cropping to control the depth of the water table and the soil salinity
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