Yellowish green poisonous and pungent-smelling gas (Cl) or element. The name (chlôrós = green) is derived from the yellow-green color of the chlorine gas. Due to its reactivity, it does not occur in nature in elemental form, but predominantly in the form of salts as sodium chloride (table salt) and potassium chloride. When nutrient it is from the Rebstock if needed in only small quantities. A deficiency in the vineyard hardly occurs. Younger vines react very sensitively to a not so rare surplus income deducted, That's why a necessary potassium fertilization in the form of potassium chloride (two-substance fertilization) only very metered or in the form of potassium sulfate. Organic chlorine compounds are harmful to health and especially toxic to insects and are therefore considered insecticides used.