A system for installation of continuous elongated tubular material in the ground involves: an agricultural tractor having a rear three-point tractor hitch, a rear drawbar and rotatable elastomeric ground-engaging interfaces; a plow mount comprising a front three-point mount hitch for connection to the rear three-point tractor hitch and a clamping connector for connection to the drawbar; and, a plow comprising a depth-adjustable blade, the plow mountable on the plow mount.

A hydraulic system for a three-point hitch includes at least one hitch cylinder and a first flow path. The hydraulic system includes a hitch valve fluidly coupled to the at least one hitch cylinder via the first flow path, wherein the hitch valve is configured to control a flow of hydraulic fluid to the at least one hitch cylinder. The hydraulic system includes a second flow path fluidly coupled to the first flow path at a first location between the at least one hitch cylinder and the hitch valve, wherein the second flow path is fluidly coupled to a reservoir for the hydraulic fluid. The hydraulic system includes a first check valve disposed along the second flow path between the first flow path and the reservoir, wherein the first check valve is configured to keep air from entering the hydraulic system via the second flow path from the reservoir.

A working machine includes a driver, a control valve, and a controller. The driver includes a hydraulic actuator and a driven body to be driven by the hydraulic actuator. The control valve regulates a hydraulic fluid to operate the hydraulic actuator. The controller is configured or programmed to control the control valve. Before starting to execute drive control for the driven body, the controller is configured or programmed to perform preliminary control to open the control valve by an opening amount that is less than an opening amount during the drive control.

A working vehicle includes a travel vehicle body, a traveling device to support the travel vehicle body such that the travel vehicle body is allowed to travel, a linkage on the travel vehicle body to link a working device thereto, a drive actuator to move the linkage in an up-down direction to raise and lower the working device linked to the linkage, and a controller configured or programmed to perform a vibration control to control the drive actuator to vibrate the linkage.