Abstract: A variable rate "on the go" fertilizer application controller for use with an agricultural earth working implement comprising a controlled metering device mounted on the implement. The control includes a reversible motor that operates a valve in the meter and at the same time a power take-off from the valve actuator drive operates a calibrated dial indicator to be interpreted by an operator so that action may be taken by a remote control device to make adjustments to compensate for variable soil conditions to get optimum crop production.