The essential elements, Cloride, Molybdenum, Cobalt and Vanadium, are not as well known as the others. However, improved understanding of their roles in plants can increase productivity.

Deficiency symptoms:

Symptoms include wilting, stubby roots, chlorosis (yellowing) and bronzing. Odours in some plants may be decreased.

Functions in plant:

Chlorine is involved in osmosis (movement of water or solutes in cells), the ionic balance necessary for plants to take up mineral elements and in photosynthesis.

Mobility in plant: Chloride, the ionic form of chlorine used by plants, is usually found in soluble forms and is lost by leaching.
Level in soil: The soil chloride supply is interpreted as deficient for cereal grain crops when there are fewer than 60 lbs Cl/acre in the surface 24 inches of soil.
Adequate level in plants: In many plants the optimum levels of chloride concentration in plant tissue are unknown. Depending on the plant species and soil chloride supply, plant tissue concentrations can range from 0.1 to 2.0% Cl. Some species appear to be healthy with only 0.01% Cl in their plant tissue. Small grains and corn need a minimum of 0.4% Cl in their tissue to achieve their full yield potential. In some crops, concentrations greater than 0.5% Cl can lower crop yield and quality.