The degree of soil deficiency and crop need help to define the amount of K-Mag to apply to meet the sulfur requirement. Soil testing for sulfur is not as reliable for predicting sulfur availability throughout the growing season as for other nutrients. Plant tissue analysis can be helpful in building an experience base. Magnesium is one of the 16 essential plant nutrients for plant growth and development. It is the central atom in the chlorophyll molecule and is responsible for the plant leaf trapping sunlight.
Energy transfer is the central function of plants.
Lighter soils with low cation exchange capacity may not hold adequate magnesium where it is needed. Soils derived from parent materials void of magnesium also may be deficient. In these situations, a readily available, water soluble source of magnesium may be needed. One of the 16 essential elements for plant growth and development, sulfur is used by all plant tissue for protein synthesis and is a component of some of the amino acids that are the building blocks of proteins. Soil tests for sulfur are not always reliable.