Soluble salts are actually naturally occurring minerals in the soil. Plants need a certain amount of these salts to grow, thrive and reproduce. However, if there are too many soluble salts in the soil, it leads to
alkalinity.
In non-arid conditions, soluble salts will leach down through the soil, leaving enough traces to satisfy the needs of the plants. However, high evaporation rates, poor drainage, low precipitation and high temperatures can prevent the salts from leaching down into the soil. Instead, they stay at the upper levels, which is the planting or growing zone.
The level of salinity in the soil is measured by the electrical conductivity of the soil. The greater the conductivity, the more alkaline the soil is. This establishes the pH value of the soil.
Many, if not most plants require a more
acidic
soil (pH below 6.5). However, many native desert and prairie plants can and do survive and thrive in soils that are more alkaline.
The best way to kind out how much soluble salts are in your garden soil is through a
soil test.
These tests, usually conducted by your state agricultural college, will give you an idea of what your soil needs, and what it already has. The fees for such a test are nominal. You can usually obtain a soil testing kit from your local Cooperative Extension office.
