How does salt in soil affect humans?

Salinity becomes a problem when enough salts accumulate in the root zone to negatively affect plant growth. Excess salts in the root zone hinder plant roots from withdrawing water from surrounding soil. This lowers the amount of water available to the plant, regardless of the amount of water actually in the root zone. The main point is that excess salinity in soil water can decrease plant available water and cause plant stress. Decreased plant growth translates into less agriculture to sustain human population and surrounding ecosystems.