Growing plants are nourished by certain constituents which they absorb from the soil and air. The chief elements drawn from tho soil are potassium, calcium, sulphur, phosphorus, and nitrogen; other elements such as silicon, iron, sodium, magnesium, and chlorine are taken up to a less degree. The natural weathering of the minerals in the ground usually provide the elements necessary to plant life; but the supply of potassium, phosphorus, and nitrogen may be insufficient and become exhausted by frequent repetitions of the same crops on the same land. The soil becomes less productive, and finally the crops are failures.
|Organic Chemistry for the industry |
Inorganic Chemistry for the industry