calcium & magnesium determine the soil’s mechanical properties
the amount of calcium versus magnesium on the exchange points determines if the soil is open & airy or loose or tight & airless (too much Mg means tight & airless soil)
this ratio also determines if the clay portions cling to themselves or open and separate
If Ca is in excess, and Mg is deficient, soil is extremely loose; water flows through without sticking; getting Mg levels to target will improve this
also, this ratio has much more effect on the soil’s air supply than does organic matter
when calcium:magnesium ratio is correct, less compost is needed
ideal ratio for non-calcareous soil: Ca:Mg = 68:12
involved in the osmotic potential, balancing anions, controlling membrane permeability & electropotential
is a component of chlorophyll
is a cofactor in most enzymes that are involved in energy transactions using ATP & ADP
stabilizes ribosome particles involved in protein synthesis
Magnesium Deficiency Symptoms:
yellowing and cell death around the edges of the leaves, or in between veins (may be confused with potassium deficiency)
Over-watering locks up magnesium in the soil, which causes yellowing of lower leaves between veins (veins remain green)
Magnesium is very mobile within the plant, so deficiency symptoms will first show in the older leaves, since the plant is moving Mg from older leaves to newer growth to supply growing points