Tull, Jethro 1674-1741
Tull was an English farmer and agricultural writer.
He developed the horse hoe and seed drill and published The Horse-Hoeing Husbandry 1633, "which contained advice on plant culture as well as ideas on plant physiology." He believed that the earth was the plant's food and was absorbed and digested by the plant, therefore, continued cultivation divided the earth into small particles which the plant could absorb. The air was useful to the plant only as a place into which to throw off waste products. Roots were the stomach and the intestines of plants. Leaves were lungs and sap was blood. Manure he said caused bad flavor in crops.