quick drop circuit for example the present invention allows for the advantages of a quick drop valve that is triggered at a clearly identifiable position of the operator controlled lever further location of the quick drop actuation at an extreme of the range of movement of operator controlled lever 52 provides for a greater modulation range of operator controlled lever 52 resulting in a greater control of the movement of blade 14 especially in a controlled lowering operation the present invention utilizes a fluidly controlled quick drop valve and thus avoids the drawbacks of a fully electrically controlled quick drop valve such fully electrically controlled quick drop valves require added components to take into account for example the need to deactivate the quick drop valve when the blade reaches the ground further fully electrically controlled quick drop systems are less reliable than systems incorporating hydraulic circuits other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein for example pilot circuit 32 of the auxiliary control system could be replaced with an equivalent gas or electric circuit for biasing quick drop valve member 100 in its first position the auxiliary control system could also be integrated with the hydraulic circuit 12 so that hydraulic fluid of hydraulic circuit 12 acts to bias quick drop valve member 100.