Here at Ceres, we have boots on the ground helping to turn imagery into action. One of the tools of choice is known as the pressure chamber, also known as a “pressure bomb”, a great tool to measure the stress of a plant. This, in turn, can help inform decisions on when to irrigate an orchard.
In simplest terms, the pressure chamber can be thought of as measuring the "blood pressure" of a plant with a couple of key differences. In plants, the vital fluid is water rather than blood, and the water is not pumped by a heart using positive pressure but rather pulled by suction (as water evaporates from the leaves) and capillary action.
Water has free energy i.e. a capacity to do work. In plants, water’s free energy (or chemical potential) is usually referred to as “water potential.” Pure water will have a water potential of 0 bars (“bar” being the unit of measurement). A pressure chamber measures water potential. By applying pressure to a plant’s fresh cut leaf and comparing the results to researched charts, one can determine how much stress a plant is under and determine when to irrigate next.
