Soil salinity is the concentration of salts found in the soil. High salinity in soils can be a problem. Plant vigor will be compromised, seed germination will be poor and, if the salinity is high enough, plants may wilt and die.
Effects of Salinity on Plants
As the concentration of salt ions increases in soil, plants have a lower ability to take up water from the soil. Plant roots contain varying concentrations of ions. As the salinity of the soil reaches that of the roots, the natural flow of water from the soil into the roots is disrupted.
If the salinity of the soil reaches high enough levels, water my actually flow out of the roots into the soil. Roots of various species have different ion concentrations, hence, the tolerance of plants to salinity differs.
Reclaiming Saline Soils
Salt leaching is a viable option to reduce soil salinity, however, this method can use a significant amount of water. Here are the basic steps to reduce soil salinity:
- Increase drainage- Drainage is essential for reclaiming saline soils. Water must move though the soils to leach salts below the root zone. If there is poor drainage on the site, tilling the soil may be necessary. Adding an organic amendment to increase drainage after tilling is recommended.
- After the soil structure had been improved and drainage established, apply clean irrigation water the site to leach salts. A general guide is 6 inches of water to reduce salinity levels by 50%, 12 inches for 80% and 24 inches for 90%.
Water application for leaching should be applied over a series of days. Overhead sprinklers may be used. Be sure to allow for infiltration when using sprinklers to avoid runoff. Flood irrigation is also an acceptable method.
Soil Salinity and Water-Wise Landscaping
Soil testing can give you an idea of the salinity levels of your yard. Choosing water conserving plants that tolerate higher salinity levels is the best option for a water-wise landscape.