Agriculture Reference
In-Depth Information
Electrode Dimensions
When it comes to determining the size of the electrodes you want to use, for simple
experiments (e.g. in small containers), the size doesn't really matter that much as long as
there is a path for the current to travel through the soil and come into contact with the root
system. Asmentioned earlier,toget better performance, it wouldbeadvisable touselarger
surface-area electrodes as they would better guarantee that the electrical current will come
into contact with most or possibly the entire root mass of the plants.
It's worth noting that the path that the electricity takes will always be unknown, especially
in outdoor soils where soils are generally not consistently mixed, and a variety of objects
and ground conditions can cause the electrical current to take varying paths to get to the
other side. That's why having a large electrode is beneficial as it helps with offering many
more paths to make it to the other side, while also helping to ensure that more biological
material is in contact with the electric field.
While the dimensions affect the radiated electric field, they also affect the current density,
which by definition is the ratio of current per electrode surface area (i.e. current in Amps /
surface area). So generally speaking, a smaller electrode will have a larger current density
compared to a larger electrode which can have a much smaller current density. This value
may also have an effect on how well plants respond. If a larger voltage is used with a
pair of electrodes that have a high current density, it may be harmful to the plant roots. So
if adverse results are observed, consider using larger electrodes as well as the operating
voltage.
Distance Between Electrodes
When designing your system, if you desire more current (or a larger electric field strength)
to be passed through the plant(s), you will need to pay attention to the distance between
the electrodes, too. A rule of thumb is that the closer the electrodes are to one another, the
stronger the electric field will be. The electric field is the ratio between the applied voltage
and the distance between the two electrodes (Voltage / distance). Theoretically, the electric
field strength should be constant throughout the region between the electrodes. In reality
though, it is going to vary due to the varied electrical conditions that are present.
field strengths range between 10 mV/m and 10 V/m. In US measurements, the range
becomes 3.3 mV/foot to 3.3V/foot. Keep in mind that the electric field strengths that may
