USE OF BIOPHYSICAL METHODS TO IMPROVE YIELDS AND QUALITY OF AGRICULTURAL PRODUCTS

Until as recently as a century ago, the exposure of biological systems to radiation was limited only to the natural sources. Today, however, a broad range of radiation types and doses have found a wide variety of uses and applications, so much so that it would be difficult to make a list of all the areas of human activity in which radiation is used for one purpose or another. The study of radiation effects on individuals and populations as a whole has become important only with the development of methods and sources of man-made radiation. Given that what is present in this case are physical effects on biological systems (living organisms), all these methods can be placed under the heading of biophysical influences . In the last 50 years, the effects of extremely low-frequency electromagnetic fields (ELF-EMF) have been studied with great diligence. These fields are the ones most commonly found in the human environment and they have been used in our studies in this field. The present paper provides a brief review of the literature data and our findings on the effects of ELF-EMF on various crop species using the RIES (Resonant Impulse Electromagnetic Stimulation) method, developed at the Faculty of Agriculture of the University of Novi Sad.

time led to the endangerment of agroecosystems.Although the potentials of conventional crop growing technologies have not been fully exhausted yet, new approaches have started to appear in agricultural production.The 21st century in agriculture will be marked by new technologies, and these will without a doubt include biophysical methods.
Until as recently as 15 years ago, which was when we began our work on the application of extremely low-frequency (ELF) electromagnetic fields (EMF) in agriculture, many physicists insisted that such low frequencies were incapable of producing any significant effect in plants.Nowadays, however, a critical number of findings have been obtained that clearly identify changes occurring in plants as a result of biophysical influences Most scientists agree that the cell membrane is the primary location at which these interactions occur, with the processes continuing in the cell afterwards.P i a c e n t i n i et al. (2001) indicate that ELF-EMF may have a stimulatory or inhibitory effect on plant tissue growth depending on the plant species involved.According to M a r i n k o v i ñ et al. (2002, 2003), the nature of the effect also depends on the hybrid, seasonal biological rhythms, field frequencies, period of exposure, and geomagnetism of the microsite.K a l i n i n et al. ( 2001) indicate ELF-EMF may have: I energetic effects, II biophysical and biochemical effects, III informational effects.
The great amount of attention given to the effects of the electromagnetic field in agriculture has been due to the possibility of being able to exert influence on plant growth and thus produce significant economic effects.

Types of electromagnetic radiation (based on photon wavelength and energy):
I Ionizing radiation, II UV radiation (that incorporates several bands, with the C one being of high importance from the standpoint of biology), III Visible light, IV IR radiation, V Radio frequency radiation, VI Extremely low-frequency electromagnetic field (ELF-EMF).
Biophysical methods used in agriculture: 1. Treatments of living organisms with: UV rays, gamma rays, ultrasound, ionizing radiation, etc. 2 .Laser treatments, 3 .Dielectric separation and stimulation of seeds, 4. Magnetic stimulation, 5 .Electromagnetic stimulation, 6. Use of ELF-EMF, 7 .The golden section principle, the EMF principle of the Great Pyramid of Giza, 8. Weed control using high electromagnetic frequencies, 9. Cold electron plasma (e -).This paper will discuss in greater or lesser detail some of the above effects as they pertain to plant growing and will describe the various findings obtained in the field domestically and internationally.
A study conducted in Urbino, Italy by Piacentini et al. (2001) showed that there is an interaction between ELF-EMF and biological systems.The interaction starts at the cell membrane level and proceeds further from there.The study was performed on cells undergoing mitosis and the growth and development of the whole plant was found to be affected.It was determined that ELF-EMF affects the phosphoinositide signal that triggers transduction, activating phosphoinositide-dependent phospholipase C, which reduces the concentration of phosphati-dylinositol-4,5-biphosphate.The plants were exposed to a 50 Hz ELF for a period of 10 minutes.The study's results support the proposition that the cell membrane is the primary site of ELF-EMF action.

Use of ELF-EMF has produced the following results:
M a r i n k o v i ñ et al. (2002,2003,2004,2006) obtained significant results using ELF-EMF on wheat and barley.The above-ground weight of the seedlings increased by an average of 23.5% (1.2 mg/plant), while root weight increased by 46% (3.1 mg/plant).The yields in small-plot trials and commercial growing conditions increased by 310-1,620 kgha -1 , while the protein content grew by 0.09-0.56%.Grzegorz and Leszek (2006) reported statistically significant increases of 3.0 and 4.1% in naked barley and oats, respectively.The protein percentage increased by 1.5-5.3%.In B h a t n a g a r et al. (1978), nitrate reductase activity was higher in seeds treated with the EMF, and the roots and stems developed at a higher rate as well.Similar findings were reported by C h a u h a n and A g a rw a l (1977), while A k s y n o v et al. ( 2001) found that ELF-EMF affected wheat germinability and caused changes in germination, viscosity, pH value, and esterase activity.In a study on wheat conducted by P h i r k e et al. (1996), the best results were obtained by rotating a magnetic disc at 800 rpm for 21-22 minutes with a magnertic field strength of 0.10 T.
Studies of ELF-EMF in maize carried out by M a r i n k o v i ñ et al. (2002,2003) showed that ELF-EMF increased seedling root weight by 37% (28 mg/ plant) and above-ground weight by 31% (22.0 mg/plant).In commercial growing conditions, grain yields were increased by 980-1,616 kgha -1 (8.4-18.7% on average across six localities).1998) studied the influence of 1-100 Hz 500 µT ELF-EMF in buckwheat, green shiso, radish, and Welsh onion and determined that each of the species had its own ideal ELF-EMF range (in radish, for example, the 1 Hz increased germinability by 30%).S p i l d e (1989) observed that ELF-EMF may have not only a stimulatory but also an inhibitory effect on germinability.Bondarenko et al. (1996) and S p i n u et al. (1998) achieved positive effects watering vegetables with magnetically treated water, with the yield increases being in the 10-20% range.In a study on tomato by Wa r d (1996), treatment with an electric current of 12 V and 2.5 x 10 -4 A resulted in plant weigh reduction, and the treated plants had an increased concentration of potassium as well.
K u l j a n å i ñ et al. ( 2002) managed to increase vine yields by 550-1,360 kgha -1 depending on variety and locality.The increases translated into financial gains of 275-680 per hectare.
According to Va s i l e v s k i ( 2003), laser treatments of carrot increased the yields of this crop by 0.78-2.55kgm -2 .The same author kept wheat seeds under pyramids made out of different materials during germination and found that this increased root length by 63.7-144.6%.
Ta r o et al. ( 2004) define electrons with an energy of less than 300 keV as low-energy electrons, or so-called soft electrons.Such electrons have been shown to have a number of advantages over gamma rays when used in the process of grain disinfection.The specific amount of energy used will vary depending on seed morphology.Thus, 60 keV are used for brown rice, 75 keV for wheat, 100 keV for white pepper, coriander, and basil, and 210 keV for black pepper.The use of electrons with such energies has been found to have no significant effect on seed quality.The first applicable treatments in this field have been developed by the Schmidt Seeger AG company and the Fraunhofer Institute for Electron Beam and Plasma Technology, as reported by C u t r u b i n i s M i h a l i s et al.

C o n c l u s i o n
• Our understanding of how ELF-EMF works is becoming increasingly clear in recent years.• More and more scientists agree that the cell membrane is the primary receptor of ELF-EMF signals, which are later transmitted further on into the cell.• The information effects of ELF-EMF in the cell have been receiving increasing attention in addition to the biochemical and biophysical ones.• The use of fast electrons (e-disinfection) has become a reality.• This method is environmentally friendly and has many other advantages over chemical disinfection.• The use of ELF-EMF produces significant yield increases.
• The above methods are inexpensive and environmentally safe.
• We hope that the day is not far when we will see massive use of these technologies in agricultural production.
C r n o b a r a c et al. (2002) reported increases of sunflower yield ranging from 222 to 390 kgha -1 and an increase of seedling weight of 21-38%.K a l i n i n et al. (2001) achieved similar results with a 3 KVT generator and 245 MHz frequency.C r n o b a r a c et al. (2002) reported that soybean yields increased by 306-658 kgha -1 and that the increases in trials were 110-1,440 kgha -1 .Similar results were reported in a paper by Va k h a r i a et al. (1991) that studied magnetic field effects in peanut.In the study, pod yield grew from 8.3 to 9.3 and 10.2 g/plant, and plant luxuriance, root length, and oil content increased as well.In a study of sugar beet carried out by M a r i n k o v i ñ et al. (2002), taproot yield grew by 4.3 to 20.6 tha -1 and sugar content increased by 0.56-1.81%.The yield of sugar increased by 950 kgha -1 on average.M a r i n k o v i ñ et al. (2002) cited potato yield increases of 2.5-6.6 tha -1 , G v o z d e n o v i ñ (2002) reported a pepper yield increase of 15 tha -1 on average, and Ta k a å et al. (2002) obtained an average yield increase of 3.1 tha -1 in tomato.Studying the effects of the micro EMF on strawberry, K o p e c e k (1972) found that the plants reached the fruit-bearing stage 20 days earlier and had better vigor.P i a c e n t i n i et al. (2001) obtained similar results with cucumber.N a m b a et al. ( (2005).S e t s u k o et al. (2000) obtained similar results using a voltage of 170-190 kV for seed disinfection.Voltages of 200 kV and above inhibit germination.Similar results were obtained by Ta k a s h i et al. (2004).The importance of microwave fields in seed disinfection is convincingly demonstrated by the findings of K a l i n i n et al. (2001) as well.