139
Electromagnetic Parameters
BOX 12.1 EXPLANATION OF THE USEFULNESS OF DIFFERENT
ELECTRICAL PARAMETERS (NORTHOLT ET AL., 2004: 56)
Life processes in plants and animals can be described as chains of electrochemical or redox
reactions. Hoffmann (1991) explains how Haas developed a bioelectric theory to derive an
electrical energy value for food from measurements of pH, redox potential and electrical
resistance. He suggested that food with high reducing power, later expressed as low P-value,
promotes health. The P-value is calculated from the three stated parameters which are
affected by the growth conditions of the product. The pH value is the best known electrochemical parameter to measure proton concentration or acidity. The pH is measured by potentiometry using suitable electrodes. The measured mV value is logarithmically transformed to
the pH value. The potentiometric equilibrium is at pH 7 and 0 mV. A difference in pH of 1
(at 25°C) equals 59 mV. In plants, proton activity has energy aspects. The redox potential
Eh (mV) refects the gradient of electrons which life processes utilise for their cellular work
(Kollath, 1978). The redox potential represents the equilibrium between oxidising and reducing substances. When redox potential is low, plant cells have more energy for their activity.
Traditionally, the fow of electrons is considered to be the main form of respiratory energy
transport in an organism with oxygen as the terminal electron acceptor. Electrical resistance R
(ohm) gives an indication of the dissipation of electrolytes in plant cells. High values of electrical resistance indicate that electrolytes are more integrated in membranes and cell organelles. Low values indicate free-moving electrolytes, which might be a sign of deterioration in
plant cells and tissues.
knowledge only a few patents have been fled and none of them are as yet applied on a commercial
scale. Undoubtedly, there may be many more examples.
Blackman et al. (1923) performed detailed research on the effect of a positively loaded discharge
point just above the top of grounded cereal plants, showing it had a lasting effect on the growth rate
of barley sheaths. Similar trials in which the direction of the current was reversed did not give the
same positive effects, and in some cases results were even negative. So the direction of the current
appeared to be important.
Rajda (2004) managed to enhance plant growth by putting a DC voltage on positive and negative
electrodes on opposite sides of the substrate in a growing table. However, the mode of action was
not explained and could be caused directly by the potential difference or by electrolytic effects on
the dissolved nutrients. Wawrecki and Zagorska-Marek (2007) demonstrated that even a weak (1
V/cm) DC electric feld with a horizontal direction disturbed the pattern of cell divisions in plant
root meristems of maize. This in turn changed the global organisation of the root apical meristem: it
infuenced the direction of apical root growth. A feld of slightly higher strength also damaged root
cap initials, terminating their division. This implies that care should be taken when applying this
technique and not to apply too high an intensity of treatment. It is not clear if and how this phenomenon could be used to the beneft of growers/farmers. But one could image that stray current 8 could
not only affect farm animals but also crops in a way that is not yet understood.
Gasner (2013) demonstrated a positive effect of grounding the root medium of pepper plants
grown in pots. Devices were inserted into the plants’ growing medium at an angle towards the
centre of the pot and connected to earth. Grounded plants grew better and produced more fruits
than ungrounded plants. The measure of grounding provided the plants with a continuous stream of
electrons from the earth, which could also be measured. The voltage between grounded plants and
8 Stray current refers to the electricity fow via buildings, ground or equipment due to electrical supply system imbalances
or wiring faws. It refers to an existence of electrical potential that can be found between objects that should not be subjected to voltage.
Electromagnetic Parameters
BOX 12.1 EXPLANATION OF THE USEFULNESS OF DIFFERENT
ELECTRICAL PARAMETERS (NORTHOLT ET AL., 2004: 56)
Life processes in plants and animals can be described as chains of electrochemical or redox
reactions. Hoffmann (1991) explains how Haas developed a bioelectric theory to derive an
electrical energy value for food from measurements of pH, redox potential and electrical
resistance. He suggested that food with high reducing power, later expressed as low P-value,
promotes health. The P-value is calculated from the three stated parameters which are
affected by the growth conditions of the product. The pH value is the best known electrochemical parameter to measure proton concentration or acidity. The pH is measured by potentiometry using suitable electrodes. The measured mV value is logarithmically transformed to
the pH value. The potentiometric equilibrium is at pH 7 and 0 mV. A difference in pH of 1
(at 25°C) equals 59 mV. In plants, proton activity has energy aspects. The redox potential
Eh (mV) refects the gradient of electrons which life processes utilise for their cellular work
(Kollath, 1978). The redox potential represents the equilibrium between oxidising and reducing substances. When redox potential is low, plant cells have more energy for their activity.
Traditionally, the fow of electrons is considered to be the main form of respiratory energy
transport in an organism with oxygen as the terminal electron acceptor. Electrical resistance R
(ohm) gives an indication of the dissipation of electrolytes in plant cells. High values of electrical resistance indicate that electrolytes are more integrated in membranes and cell organelles. Low values indicate free-moving electrolytes, which might be a sign of deterioration in
plant cells and tissues.
knowledge only a few patents have been fled and none of them are as yet applied on a commercial
scale. Undoubtedly, there may be many more examples.
Blackman et al. (1923) performed detailed research on the effect of a positively loaded discharge
point just above the top of grounded cereal plants, showing it had a lasting effect on the growth rate
of barley sheaths. Similar trials in which the direction of the current was reversed did not give the
same positive effects, and in some cases results were even negative. So the direction of the current
appeared to be important.
Rajda (2004) managed to enhance plant growth by putting a DC voltage on positive and negative
electrodes on opposite sides of the substrate in a growing table. However, the mode of action was
not explained and could be caused directly by the potential difference or by electrolytic effects on
the dissolved nutrients. Wawrecki and Zagorska-Marek (2007) demonstrated that even a weak (1
V/cm) DC electric feld with a horizontal direction disturbed the pattern of cell divisions in plant
root meristems of maize. This in turn changed the global organisation of the root apical meristem: it
infuenced the direction of apical root growth. A feld of slightly higher strength also damaged root
cap initials, terminating their division. This implies that care should be taken when applying this
technique and not to apply too high an intensity of treatment. It is not clear if and how this phenomenon could be used to the beneft of growers/farmers. But one could image that stray current 8 could
not only affect farm animals but also crops in a way that is not yet understood.
Gasner (2013) demonstrated a positive effect of grounding the root medium of pepper plants
grown in pots. Devices were inserted into the plants’ growing medium at an angle towards the
centre of the pot and connected to earth. Grounded plants grew better and produced more fruits
than ungrounded plants. The measure of grounding provided the plants with a continuous stream of
electrons from the earth, which could also be measured. The voltage between grounded plants and
8 Stray current refers to the electricity fow via buildings, ground or equipment due to electrical supply system imbalances
or wiring faws. It refers to an existence of electrical potential that can be found between objects that should not be subjected to voltage.