The bacterial action on salt compounds causes a disassociation of salt from the soil particles. The inert ingredients in commercial fertilizer are salt compound used by fertilizer companies to bind plant nutrients into a stable form. In this binding process, the nutrients and water also become unavailable to the plant. This is further explained by the graph and comments shown below.
Sodic soils are low in the kinds of salts found in saline soils, but they are high in sodium.
The resulting high pH, which is more than 8.5 can limit the growth of many crops. For most crops, the main effect of sodium is the destruction of soil structure. When sodium ions saturate cation exchange sites, the colloids separate and disperse soil aggregates. Tiny soil particles lodge in the soil pores, sealing the soil surface. Tilth also suffers and crusts hard enough to stop seed germination may form.