It is found in soil. Magnesium absorption by plants is conditioned by three main factors: the amount of land accessible, magnesium interactions with other elements and requirements of the plant. Insufficient magnesium produces necrosis of leaves. Magnesium accumulate in seeds, formed with phosphoric acid, fitina.
Of all the elements, potassium is found in greatest quantity in plants, especially the young, in the form of inorganic salts.
Potassium deficiency is felt more strongly on soils with high salt content of calcium and magnesium and poor aeration. External symptom of potassium deficiency is the leaf color change, that the appearance of brown spots, especially near the extremities of the leaf.