Description of practice
Leaching is a practical way of removing excess salts. It is effective only to the extent that water moves down through the soil profile and below the root zone. It is often accomplished by occasional excessive irrigation applications to dissolve, dilute and move the salts.
| Examples of how to leach salts | Further information (see Note below) |
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Continuous pondingWater is impounded using a surface irrigation method. Continuous ponding reduces water use efficiency but increases velocity of salt leaching. |
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Intermittent pondingThe rise in water table following ponding is allowed to subside before water is next applied. Leaching salt with intermittent ponding is appropriate in poorly drained areas with low evaporative demand. |
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Rainwater leachingIn areas where good quality water is scarce, rainwater is collected during the rainy (monsoon) period to be used for salt leaching. |
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Sprinkler leachingSprinkler irrigation is used to leach salt with the advantage that water can be applied to unprepared fields. It is an efficient method on coarser textured soils as application losses are lower than with surface irrigation. |
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Alternate row irrigationAlternate row irrigation is used in high water table areas to reduce salt accumulation. Every other row is flooded to remove salts into the unirrigated area. |
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Note: Most of the Further information links are to a full description of the example in the WOCAT database. However sometimes the link may be to similar practices or a research paper. Occasionally the link is to a commercial product in which case it should be understood that this does not imply any endorsement of the product by iSQAPER.