Abstract: A conservation tillage attachment for a seed planting unit that functions to cut and clear away prior crop residue, fracture the soil ahead of the seed trench opener, and form a trench for the deposit of dry or liquid fertilizer offset from and parallel to the later formed seed trench. The attachment includes a single disk blade disposed forward of the seed trench forming unit. The single disk blade is disposed at an angle of approximately 5.degree. from the line defining the direction of travel of the seed planting implement. The attachment includes a selectively adjustable down force structure and a selectively adjustable depth control mechanism.

Abstract: Hydraulic center and lock structure for the caster wheel of, for example, a tractor-drawn plow, operative on a centering element rigid with the standard of the caster wheel for forcibly centering the standard and ultimately locking the standard against turning about its axis when the caster wheel is in its straight-ahead position. The hydraulic device is bi-directionally operative for disengagement from the centering element to enable free castering of the wheel, as when the plow is raised for transport. The invention also provides two forms hydraulic control for coordinating the raising and lowering of the plow with unlocking and locking the caster wheel. In one form, the system provides for trapping fluid in the caster wheel cylinder in its straight-ahead position, with a separate valve operated manually to release the fluid when the plow is lowered to operating condition. In another form the valve that releases the trapped fluid is made responsive to a predetermined pressure.

Abstract: In a plow, a share having a thickened rearwardly extending mid-section with narrow upper and lower edge portions. The thicker mid-section provides increased share strength and resistance to breakage to improve expected share life. The upper edge portion of the share abuts the moldboard and is provided with a cross sectional thickness consistent with the cross sectional thickness of the moldboard to assure a continuously concave soil working surface over the share and onto the moldboard. The frog support is provided with a flat share supporting surface to reduce frog forming expense and a concave moldboard receiving surface to assure that the moldboard assumes the proper soil working surface when mounted.