Abstract: A fertilizer knife for subsurface application of fertilizer in liquid or vapor form in a ground furrow comprises a narrow, elongated blade having a width W.sub.1, a leading edge with a soil breaking segment and a trailing edge. An elongated, hollow, fertilizer conduit having a width W.sub.2 is located behind the trailing edge and is shaped to correspond to the trailing edge. A foot portion on the blade has a bottom edge extending from the leading edge upwardly toward and beyond the trailing edge to form a rearwardly extending shoulder. The conduit terminates above and is spaced from the shoulder to prevent back pressure in the conduit during movement of the knife through the furrow and to provide for flow of fertilizer away from vertical walls of the furrow. A hard, abrasion-resistant material over the soil-breaking segment forms a substantially flat surface having a width W.sub.3 on the leading edge. Soil contacting surfaces on the blade and conduit are covered by a dried, abrasion-resistant coating.