What is the difference between water content versus water potential?
When dealing with any wet material such as soil or plant tissue, there are two important properties related to water. Water content is how much water the material holds, expressed as 30% water or 0.3 grams of water per cubic centimeter of soil. The water potential is how tightly the tissue holds the water. This can be illustrated by thinking of a sponge and a chunk of clay. It is easy it is to squeeze almost all the water out of a wet sponge, but much harder to squeeze of out of the wet clay even though both may have the same water content when wet.
For knowing the water stress that plants are feeling, what is the best measurement?
The performance of plants (growth, opening of stomatal pores on leaves to allow photosynthesis and evaporative cooling, movement of sugars and minerals, etc.) depends on the water potential or how hard the plant has to fight to extract enough water from the soil. So for understanding the amount of stress plants sense, measuring the water potential is best, especially if it is measured directly inside the plant. For this reason, we developed the FloraPulse microtensiometer.
How have you tested the sensor?
FloraPulse has done months-long field trials in winegrapes, almonds and apple. We have corroborated that our patented sensor measures plant water-stress accurately, and that the data agrees with the gold standard: the pressure chamber. We thus have a sensor that is as good as having someone in the field continually plucking leaves and measuring water stress manually, only more accurately and reliably.
Field trial in Matchbook Winery, Merlot winegrapes:
Field trial in Done-Again Farms, nonpareil almonds:
Is it true your sensors captured the solar eclipse?
Yes. Our sensors captured the increase in water potential in almond trees when the moon blocked the sunlight on August 21, 2017 from 9:30 am to 11:45 am. Notice the bump in measured water potential in the plot below.
Is the sensor patented?
Yes. FloraPulse has licensed two granted patents from Cornell University: US Patent numbers 8,695,407 and 9,766,173.