Plant nutrition is necessary for plant growth. There are several principles that apply to plant nutrition. Some elements are essential, meaning that the absence of a given mineral element will cause the plant to fail to complete its life cycle; that the element cannot be replaced by the presence of another element; and that the element is directly involved in plant metabolism. However, this principle does not leave any room for the so-called beneficial elements, whose presence, while not required, has clear positive effects on plant growth.