Comparison effect of pulse-power generated electromagnetic field on the growth rate of green soybean

Abstract

This research is to investigate and make preliminary comparison on the effect 50 Hz sine waveform of pulsed magnetic field on the growth rate of green soybean with a variety of magnetic field values (600 mG, 100 mG, 70 mG, 20 mG, 8 mG and 3 mG). A circuit consisting of excitation ferrite-core coil, diode, power MOSFET, resistor, function generator and power supply has been designed and developed to generate pulse magnetic field. It has the ability to produce a stable value of magnetic field operating at a frequency of 50 Hz. Selected green soybean seeds were exposed to three types of waveforms, namely sine wave, square wave and sawtooth wave at 50 Hz. In the experiment, 400 seeds of green soybean arranged in a straight line were exposed to magnetic field in the range of 3 to 600 mG. Values of the magnetic field have been determined by the distance between source (excitation ferrite-core coil) and subject (green soybean). The experiment was conducted for a duration of seven days and samples were taken randomly. The experiment was conducted into two different parts: in the first three days the experiment was conducted in the dark and second four successive day of experiment was conducted under daylight. The results of sine wave show that six magnetic field values at root inhibit the germination rate while six magnetic field values at hypocotyls part has sped up growth rate. Moreover, growth rate at leaf part has been sped up but only for 70 mG magnetic field. In the sawtooth experiment, only three magnetic values (20 mG, 8 mG and 3 mG) show speed up progress on growth rate, while others show the sign of decreasing germination and growth rates for root and leaf part. Lastly, for the square wave, all the seeds were exposed to six different magnetic field values (600 mG, 100 mG, 70 mG, 20 mG, 8 mG and 3 mG) and the result show that the germination and growth rates for root, hypocotyls and leaf were inhibited. As a conclusion, the most pronounce effect of different waveform was sine waveform that affect to speed up the growth rate of hypocotyls and leaf.