Agricultural sampling system and related methods

A method for pumping slurry comprising:

• providing a double diaphragm slurry pump comprising a vertical longitudinal axis and a pair of first and second pumping chambers, a first and second pump head enclosing the first and second pumping chambers respectively, and a translatable operating shaft comprising a resiliently deformable diaphragm coupled to each of opposite ends of the shaft, one of the diaphragms disposed in each of the first and second pumping chambers;
• moving the operating shaft in a first direction during an intake stroke;
• drawing slurry from an inlet manifold into the first pumping chamber through a longitudinal bore of the first pump head and a lower slurry exchange bore each formed in the first pump head separate from the first pumping chamber;
• moving the operating shaft in a second direction during a pumping stroke;
• and
• expelling the slurry back through the lower slurry exchange bore during the pumping stroke from the first pumping chamber back into the longitudinal bore of the first pump head, while simultaneously expelling air from the first pumping chamber into the longitudinal bore of the first pump head through an upper air vent bore;
• and
• expelling air from the first pump chamber through an upper air vent bore during the pumping stroke into the longitudinal flow bore of the first pump head simultaneous to the step of expelling the slurry;
• wherein the upper air vent bore is smaller in diameter than the lower slurry exchange bore such that air is preferentially ejected from the first pumping chamber rather than slurry.