The Effect of Microwave Treatment on Ryegrass and Wild Radish Plants and Seeds

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1 16 Gloal Journal of Agriultural Innovation, Researh & Development, 015,, 16-4 The Effet of Mirowave Treatment on Ryegrass and Wild Radish Plants and Seeds Graham Brodie * and Eloise Hollins Melourne Shool of Land and Environment, Melourne University, Dookie Campus, Nalinga Rd., Dookie 3647, Australia Astrat: Annual ryegrass (Lolium rigidum) and wild radish (Raphanus raphanistrum) are signifiant weeds in Australian winter ropping systems. These speies have developed signifiant heriide resistane and new ontrol strategies need to e developed. Mirowave energy has een onsidered for weed ontrol for some time. The researh onsidered the effet of varying amounts of mirowave energy on plants and their seeds for eah speies. Several experiments explored the interation etween mirowave energy and seed depth in the soil. Plant responses to mirowave energy were also determined for eah speies. Seed treatment requires higher energy appliations than plant treatment and is oneptually similar to soil fumigation treatments. Soil treatment may have appliation in some high value hortiultural rops, whih already use soil fumigation. Mirowave treatment of plants requires less energy, with wild radish requiring out 60 J m - to ahieve 100% mortality, while ryegrass plants require out 370 J m - to ahieve 100% mortality. Mirowave treatment of growing plants an e ompared to the appliation of heriide. Therefore ontrol of growing plants should e the fous of developing a ommerially vile mirowave weed ontrol devie for ropping systems. Keywords: Mirowave, weed, ryegrass, wild radish. 1. INTRODUCTION Annual ryegrass (Lolium rigidum) and wild radish (Raphanus raphanistrum) are onsidered to e the most serious and hallenging weeds of annual winter ropping systems in southern Australia [1, ]. They have developed resistanes to heriides from several groups [3] and pose a signifiant threat to the future of Australian agriulture, in regards to prodution loss [4] and finanial urdens. Interest in hemial-free weed ontrol has een inreasing due to onerns over heriide resistane, the environmental and human health impats of heriide use [5, 6], and the rise in organi farming praties. Mirowave radiation has long een onsidered as a suitle tehnology to ontrol the weed seed ank [7-9]; however, it failed to reah ommerial use. This was due to numerous studies agreeing that it was far too ineffiient and impratial for road are seed ank ontrol [10-13]. In spite of this, the growing onern of heriide resistane has prompted a revisit of mirowave weed ontrol tehnology, with a fous on overoming these ineffiienies. Ahieving these goals requires a etter understanding of the mirowave energy requirements for treating weeds and their seeds in the soil. *Address orrespondene to this author at the Melourne Shool of Land and Environment, Melourne University, Dookie Campus, Nalinga Rd., Dookie 3647, Australia; Tel: ; Fax: ; graham@unimel.edu.au. METHOD This researh used a series of small well defined experiments to determine the dose response urves for annual ryegrass and wild radish weeds and their seeds to varying amounts of mirowave energy. In the partiular ase of seeds, soil depth will also affet the suseptiility of seeds to mirowave treatment; therefore soil depth must e aounted for in the dose response urves for seed treatments. All experiments were run using a horn antenna to apply the mirowave energy to the plants or soil. Eah experimental treatment had at least four repliates and eah experiment was performed at least twie to verify the results..1. Estimating Mirowave Power Density from a Horn Antenna The prototype systems use in this study used a retangular wave guide feeding mirowaves into a pyramidal horn antenna, whih projets the mirowave energy vertially onto the ground. The mirowave energy generates heat within the plants and soil. Mirowave heating is diretly linked to the dieletri properties of the plants and soil and the eletrial field strength of the mirowave fields [14]; therefore it is ritial to understand the field intensity and distriution on the surfae of the soil. It is unsafe to diretly measure the field intensity near the mirowave appliator; therefore was neessary to estimate the field energy density, ased on well-estlished eletromagneti theory. E-ISSN: / Avanti Pulishers

2 The Effet of Mirowave Treatment on Ryegrass Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No The eletri field in the wave guide has a sinusoidal distriution aross the width of the guide. The peak eletri field strength (E o ) in a retangular wave guide is [15]: E o = " # $ 8! fµ o P! f % & ' ( "! % # $ a & ' Where µ o is the permeility of free spae, P is the average mirowave power (W), a is the width of the wave guide (m), is the height of the wave guide (m), and is the speed of light in free spae (m s -1 ). The distriution of the mirowave s eletri field aross the width of the waveguide, as measured from the entre line of the guide, is: " E = E o os! # $ a x ' % & ' () Where x ' is the horizontal distane in the aperture plane from the entre line of the wave guide or aperture(m). There is some expansion of the field etween the feeding wave guide and the aperture of the antenna; therefore: (1) Based on the geometry of the horn antenna sown in Figure 1, the prolem an e desried y: E P = E a 4! B + A + ( B ( A " os! # $ A x ' % & j)o ( ( x(x' ) + ( y(y' ) +z + R + ( x' ) + R + ( y' ) ) o o ' e( * dx '* dy ' ( x ( x ') + ( y ( y ') + z Where x, y, and z is the Cartesian oordinates of the point relative to the entre point of the antenna s aperture and x and y are the Cartesian oordinates of any point in the antenna s aperture plane relative to the entre point of the antenna s aperture. There is no simple losed solution to Equation (4); however it an e evaluated numerially using a Simpson s numerial surfae integral approximation. This numerial integration was oded using MatL and used to estimate the field energy intensity on a plane at ground level for various heights of the horn antenna ove the ground plane. This is essential to properly determine the dose responses of weeds and their seeds to applied mirowave energy. Figure shows the estimated field strength as a funtion of range from the horn antenna to the ground plane and lateral distane from the entre line of the horn antenna. (4) " E a = E o os! # $ A x ' % & ' ( a A (3) Where A is the width of the aperture (m). In order to properly understand the field intensity at the soil surfae, and therefore determine the mirowave energy that has een applied to the soil, an analysis of the mirowave field intensity immediately in front of a pyramidal horn antenna (in the Near Field) is required. This prolem is not trivial. Figure : Estimated mirowave field strength at ground level from a kw mirowave system as a funtion of height of the 110mm y 55mm antenna ove the ground... Experiment 1 Ryegrass Seed Treatment in Sand Figure 1: Geometry of a horn antenna showing a propagating wave front in the flare of the antenna [16]. The loratory mirowave system (Figure 3), ased on a modified 750 W mirowave oven operating at.45 GHz, had an 86 43mm retangular waveguide hannelling the mirowaves from the oven's magnetron to a pyramidal horn antenna with aperture dimensions of mm.

3 18 Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No. 1 Brodie and Hollins After the sand had ooled, the seeds were extrated and plaed on top of moist otton wool and filter paper in petri dishes. The petri dishes were overed and inuated in a Contherm inuator (model CAT 150) at 8 C, whih was within the temperature range for optimal ryegrass seed germination [19]. The seeds were kept moist and heked regularly to ensure they did not dry out. The seeds were allowed to germinate for ten days. Seeds were regarded as having germinated if the radial had emerged. Figure 3: Mirowave prototype system ased on a modified mirowave oven. Fine uilder's sand was used for this experiment. Dry sand has the lowest dieletri onstant at mirowave frequenies of any air-dry soil type [17, 18]. Therefore, sand was hosen to represent the worst ase senario for mirowave treatment of soil seed anks. The sand was sieved through a 1mm soil sieve to ensure homogeneity of soil ehaviour during the experiments. The sand was air-dried during summer and then stored in a warm dry environment until used in the experiments. Gravimetri analysis, ased on weights efore and after drying for 4 h at 105 C, was used to determine that the moisture ontent of the airdry sand was 1.0%. A 5 4 fatorial experiment was onduted. Fator A involved soils at two moisture levels: air dry and 0% water y volume. The wet soil was prepared y mixing four parts y volume of sand with one part y volume of water and then mixing thoroughly y hand. Fator B omprised five mirowave heating times: 0,, 4, 8, and 1 min. Fator C involved urying the ryegrass seeds at four different depths (0,, 5, or 10 m) from the surfae of the soil that was exposed to the mirowave energy. Samples of twenty seeds were plaed into paper envelopes made from folded filter paper to failitate easy reovery from the soil after treatment. Fifty two pots were used in the experimental protool, with four seed envelopes plaed in the entre of eah pot at the appropriate depth from the surfae. The pots were allowed to stand for at least 15 min efore any experimental proedures were imposed. This allowed the seeds and seed envelopes to reah thermal and moisture equilirium with the sand. Pots were plaed under the horn antenna of the mirowave prototype at a range of 0mm from the antenna s aperture and exposed to mirowave treatment for the appropriate amount of time..3. Experiment Ryegrass Seed Treatment in Soil Thirty five soil samples were randomly exavated from the top 3 m of a paddok at the Dookie ampus of the University of Melourne that was predominantly Currawa Loam. The soil was layered into pots with sets of 5 ryegrass seeds in paper envelopes plaed at depths of 0,, 5, 10 and 0 m within eah pot. The pots reeived 500 ml of water to reah a onsistent moisture level and left overnight. This mirowave treatment was applied using a kw mirowave system operating at.54 GHz feeding into a horn antenna with aperture dimensions of 110mm y 55mm. Eah pot was plaed under the mirowave antenna at a range of 70mm from the antenna s aperture for treatment durations of 0,, 5, 10, 30 and 10 seonds. Pots were left to return to amient temperature. After ooling, eah layer of seeds was arefully removed and plaed into individual ags lelled with the pot numer, treatment and soil depth. In order to promote germination, seeds were plaed etween layers moistened paper towel, within a small, open plasti ag and kept in a warm, dark plae. The paper towel was remoistened eah day. After 10 days, the total numer of germinated seeds was reorded to determine the perentage of germination following mirowave treatment..4. Experiment 3 Ryegrass Plants in Soil Ninety soil samples from the top 3 m of the same paddok as used in Experiment were exavated and plaed into pots. Eah pot was alloated 0 annual ryegrass seeds, whih were grown for nine weeks. The seeds were randomly plaed on the soil surfae and topped with a shallow overing of soil. Initially, the seeds were watered in with 500 ml of water per pot. Over the growing period, pots were watered with 100ml of water every 3 days to ensure the soil remained moist. After one week most seeds had germinated and

4 The Effet of Mirowave Treatment on Ryegrass Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No after a month many plants were well estlished. The total numer of estlished seeds was reorded. Three degrees of water stress were estlished to test the relationship etween water stress and mirowave treatment on ryegrass plants. One group of plants reeived a regular watering shedule of 100 ml every 3 days up until the day of mirowave treatment. This group was named Water Stress Group A. The seond degree of water stress was estlished y the essation of watering of a numer of pots 5 days prior to mirowave treatment. This group was named Water Stress Group B. A third degree of water stress was ahieved y pots in this group reeiving no water from 10 days prior to mirowave treatment. This group was named Water Stress Group C. The differene this water restrition treatment aused was determined y the gravimetri water ontents of the soils from eah water stress group. Ten randomly seleted soil samples were taken from eah group and weighed. The samples were oven dried at 105 C for 4 hours and then a dry weight was reorded to alulate the average gravimetri water ontent of eah group. One plants were well estlished, eah pot was plaed under the antenna of the kw,.45 GHz, mirowave system with a 110mm y 55mm antenna aperture at a range of 110mm, for treatment durations of 0,, 5, 10, 30 and 10 seonds. One day after treatment, all pots reeived 100 ml of water every 3 days for a total of 10 days to enourage reovery and growth of the ryegrass plants. After this time, the numer of living and dead plants in eah pot was reorded to determine the perentage of plant survival following mirowave treatment..5. Experiment 4 Wild Radish Seeds in Soil Twenty soil samples were randomly exavated from the top 3 m of a paddok at the Dookie ampus of the University of Melourne that was predominantly Currawa Loam. The soil was layered into pots with sets of 0 wild radish seeds, whih were removed from their pods and plaed into paper envelopes, at depths of 0.5, 5.0 and 9.5 m within eah pot. The pots reeived 500 ml of water to reah a onsistent moisture level and left overnight. On the following day the pots were exposed to mirowave treatment. This experiment was onduted using a.54 GHz, kw mirowave system, feeding into a horn antenna with aperture dimensions of 110mm y 55mm. Eah pot was plaed under the mirowave antenna at a range of 55mm from the antenna s aperture for treatment durations of 0, 15, 30, 60, and 90 seonds. Pots were left to return to amient temperature. Eah layer of seeds was arefully removed and plaed onto moist filter paper in petri dishes. After 10 days, the total numer of germinated seeds was reorded to determine the perentage of germination following mirowave treatment..6. Experiment 5 Wild Radish Plants in Soil Sixty soil samples from the top 3 m of the same paddok used in Experiment were exavated and plaed into pots. Eah pot was alloated 3 to 4 wild radish seeds, whih were grown for six weeks. Initially, the seeds were watered in with 500 ml of water per pot. Over the growing period, pots were watered with 100 ml of water every 3 days to ensure the soil remained moist. Not all seeds germinated, so after three weeks, pots with more than one plant were thinned to one plant per pot. One plants had developed to a rosette stage, eah pot was plaed under the antenna of the kw,.45 GHz, mirowave system at a range of 110mm, for treatment durations of 0, 5, 10, 15, 30 and 60 seonds. One day after treatment, pots reeived 100 ml of water every 3 days for a total of 10 days to enourage growth of the plants. After this time, the numer of plants still alive was reorded to determine the perentage plant survival following mirowave treatment..7. Statistial Analyses Analysis of variane was used to determine signifiant differenes in plant and seed survival. Weed ontrol studies require the determination of dose response urves, relating applied mirowave energy (and soil depth in the ase of seeds). These were determined y regression using MatL. 3. RESULTS 3.1. Experiment 1 Ryegrass Seed Treatment in Sand Seed mortality inreasing as applied mirowave energy inreased; however inreasing urial depth redued seed mortality (Tle 1). Signifiantly less mirowave energy was needed to ahieve high seed mortality in wet sand than in dry sand (Tle 1). Seed response as a funtion of mirowave energy and seed urial depth an e desried y dose

5 0 Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No. 1 Brodie and Hollins Tle 1: Mean Ryegrass Seed Germination Perentage as a Funtion of Applied Mirowave Energy and Seed Depth - - Dry Sand Mirowave Energy J m Burial Depth (m) a a a Wet Sand Mirowave Energy J m LSD (P = 5) 5.3 Note: Entries with different supersripts are signifiantly different from one another. response surfaes. The Normalised dose response for seeds in dry sand is desried y Figure 4. Figure 4: Normalised germination response for annual ryegrass seeds in dry sand as a funtion of applied mirowave energy and seed depth. ( ) S = 0.41! erf #$ 0 E! e"7 D " 68 %& (5) - Where E is the applied mirowave energy (J m ) and D is the depth (m). The r value for this funtion is " t #z e $ dt % is the omplementary! Gaussian error funtion and assumes that the suseptiility of plants and seeds to mirowave treatment is normally distriuted. Inluding a term with the form E! e"# D will aount for the natural attenuation of the mirowave energy with depth in the soil. Note: erf ( z ) = Mirowave heating in wet sand was muh faster and therefore required far less energy to kill the ryegrass seeds (Figure 5). The Normalised dose response is desried y: ( ) S = 0.30! erf #$ E! e"7 D " 646 %& The r value for this funtion is (6) Figure 5: Normalised germination response for annual ryegrass seeds in wet sand as a funtion of applied mirowave energy and seed depth. 3.. Experiment Ryegrass Seed Treatment in Soil As in the previous experiment, ryegrass seed mortality inreased with inreasing mirowave energy, ut dereased with inreasing urial depth (Tle ). The Normalised dose response (Figure 6) is desried y: ( ) S = 0.4! erf #$ 1 E! e"45 D " %& (7) The r value for this funtion is Experiment 3 Ryegrass Plants in Soil Mirowave indued soil temperature was higher in the water stressed treatments than in the unstressed treatments (Figure 7); espeially in the highest mirowave treatment. The mean level of soil moisture for eah water stress groups varied from 5% to 14% (Figure 8), aording to the applied treatments; however there were no statistially signifiant differenes in plant responses that ould e attriuted

6 The Effet of Mirowave Treatment on Ryegrass Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No. 1 1 Tle : Mean Ryegrass Seed Germination Perentage as a Funtion of Applied Mirowave Energy and Seed Depth Burial Depth (m) Applied Mirowave Energy (J m - ) a 87.4 a a a 91.1 a a 85.7 a 89.0 a 89.1 a 89.0 a a 91.7 a 86.6 a 86.7 a 86.7 a 86. a a 89.0 a 85.3 a 84.3 a 84.8 a 85. a a 85.5 a 86. a 84.1 a 81.8 a 83.0 a 84.3 a Note: Entries with different supersripts are signifiantly different from one another. to these moisture stresses. Therefore the dose response was determined on the pooled response of all pots in the experiment (Figure 9). LSD (P = 5) 9.9 Figure 8: Gravimetri water ontent of soil following imposition of three water stress groups, A, B and C. Figure 6: Normalised germination response for annual ryegrass seeds in soil as a funtion of applied mirowave energy and seed depth. Figure 9: Response of annual ryegrass plants as a funtion of applied mirowave energy. The Normalised dose response is desried y: Figure 7: Soil temperature in relation to mirowave treatment time, aross three water stress groups A, B and C. Standard deviations shown as error ars. ( ) ( ) S = 0.17! erf #$ E " 90.7 %& +0.83! erf #$ 17 E %& (8)

7 Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No. 1 Brodie and Hollins Tle 3: Mean Wild Radish Seed Germination Perentage as a Funtion of Applied Mirowave Energy and Seed Depth - Mirowave Energy (J m ) Burial Depth (m) a LSD (P = 5) 13.6 Note: Entries with different supersripts are signifiantly different from one another. The r value for this funtion is The results from the seond repetition of this experiment were also the same as the first Experiment 4 Wild Radish Seeds in Soil Wild radish seed germination was low and varile in the ontrol treatment; however there was some germination in every repliate of the ontrol. Seed germination dereased with inreasing mirowave energy, ut inreased with inreasing urial depth (Tle 3) Experiment 5 Wild Radish Plants in Soil Wild radish plants showed only a single response to mirowave treatment (Figure 11); unlike the ryegrass plants. The Normalised dose response is desried y: S = 0.51! erf [ 6! E " 31.6 ] (10) Many seeds from the higher mirowave treatments appeared to have expressed oil during their treatment as there were distintive oil stains on the filter paper envelopes in whih the seeds were plaed (Figure 9). The dose response (Figure 10) is desried y: ( ) S = 0.16! erf #$ 4 E! e"0.1 D " 189 %& (9) The r value for this funtion is Figure 11: Response of wild radish seeds as a funtion of applied mirowave energy and soil depth. The r value for this funtion is Therefore the equivalent of an LD50 mirowave energy dose for wild - radish plants is 31.6 J m. Figure 10: Preparation of wild radish seeds for germination test after mirowave treatment (Note: oil stain on filter paper to the left, whih was used to hold seeds during mirowave treatment). Figure 1: Response of wild radish plants as a funtion of applied mirowave energy.

8 The Effet of Mirowave Treatment on Ryegrass Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No DISCUSSION This study demonstrates that mirowave energy kills ryegrass and wild radish plants and seeds in soil. Ryegrass plants show a doule response to mirowave treatment, with some effiay due to low appliation energy; however 100% mortality required 370 J m - of mirowave energy. This is proly eause grasses have their apial meristem at the ase of the plant in or near the soil surfae, where it is slightly proteted from mirowave heating y the leaves ove and the surrounding soil. This is important to onsider when designing an effetive mirowave appliator system for mirowave weed management in ropping systems. Complete wild radish plant mortality was ahieved when 60 J m - of mirowave energy was applied. This differene in energy requirements etween ryegrass and wild radish may e due to a omination of differenes in plant geometry and the loation of the apial meristems. Mirowave heating is linked to the geometry of the heated ojet [14]. Wild radish, as a road leafed plant, has larger leaf and stem strutures than ryegrass and therefore heats faster than the thinner leafs and stems of ryegrass. The apial meristems of road leafed plants are at the tips of the stems rather than at the ase of the stem as in grasses; therefore rapid mirowave heating in the strutures of road leafed plants may rupture plant stem ells [0] utting off supporting plant funtions from the apial meristems, thus preventing growth. In the ase of grasses, destrution of plant stems may not affet the apial meristems and therefore the plant an regrow. Complete ryegrass seeds mortality in the top m of dry sand was not ahieved even after applying 3,530 J m - of mirowave energy eause the dry sand has very low dieletri properties and does not sor mirowave energy very well, while omplete mortality of ryegrass seeds at the surfae of wet sand was 1,176 J m - eause moisture in the soil has a high dieletri onstant that sors mirowave energy well. Complete mortality of wild radish seeds in the top 5 m of moist soil was ahieved y applying 693 J m - of mirowave energy. This is lower than the ryegrass seeds in experiment and may e related to the geometry and relative volume of wild radish seeds when ompared to ryegrass seeds. Davis et al. [7] noted that oth speifi mass and speifi volume of seeds influened their suseptiility to mirowave damage. Weed ontrol is ahieved y interepting a plant s life yle when it is most vulnerle to the treatment method. This study demonstrates that although mirowave treatment an kill weed seeds in the soil, emerged plants are muh more vulnerle to mirowave energy; therefore mirowave weed ontrol an e est ahieved y applying mirowave energy to emerged plants. 5. CONCLUSION Mirowave treatment kills annual ryegrass and wild radish plants and their seeds in the soil. Seed treatment requires higher energy appliations than plant treatment and is oneptually similar to soil fumigation treatments. Soil treatment may have appliation in some high value hortiultural rops, whih already use soil fumigation. Mirowave treatment of plants requires less energy, with wild radish requiring out 60 J m - to ahieve 100% mortality, while ryegrass plants require out 370 J m - to ahieve 100% mortality. Mirowave treatment of growing plants an e ompared to the appliation of heriide. Therefore ontrol of growing plants should e the fous of developing a ommerially vile mirowave weed ontrol devie for ropping systems. REFERENCES [1] MGillon T and Storrie A. Integrated weed management in Australian ropping systems - A training resoure for farm advisors. CRC for Australian Weed Management: Adelaide, South Australia 006. [] Stanton R, Pratley J and Hudson D. Annual ryegrass ontrol affeted y hoie of management system. In: Proeedings Cairns, Queensland, Australia 008; [3] Heap I. The international survey of heriide resistant weeds. (aessed 1 Otoer 013. [4] Brodie G. Derivation of a Cropping System Transfer Funtion for Weed Management: Part 1 Heriide Weed Management. Gloal Journal of Agriultural Innovation, Researh & Development 014; 1 (1): [5] Relyea RA. The Lethal Impat of Roundup on Aquati and Terrestrial Amphiians. Eologial Appliations 005; 15(4): [6] Wikerham EL, Lozoff B, Shao J, Kairoti N, Xia Y and Meeker JD. Redued irth weight in relation to pestiide mixtures deteted in ord lood of full-term infants. Environment International 01; 47(0): [7] Davis FS, Wayland JR and Merkle MG. Phytotoxiity of a UHF Eletromagneti Field. Nature 1973; 41(5387): [8] Davis FS. New tehniques in weed ontrol via mirowaves. In: Proeedings to Southern Nurserymen s Assoiation Conferene. Naogdohes Texas USA. 1974;

9 4 Gloal Journal of Agriultural Innovation, Researh & Development, 015, Vol., No. 1 Brodie and Hollins [9] Davis FS, Wayland JR and Merkle MG. Ultrahigh-Frequeny Eletromagneti Fields for Weed Control: Phytotoxiity and Seletivity. Siene 1971; 173(3996): [10] Brodie G, Ryan C and Lanaster C. Mirowave tehnologies as part of an integrated weed management strategy: a review. International Journal of Agronomy [11] Vidmar M. An improved mirowave weed killer. Mirowave Journal 005; 48(10): [1] Nelson SO. A review and assessment of mirowave energy for soil treatment to ontrol pests. Üerlik und Beurteilung des Einsatzes von Mikrowellenenergie zur Shädlingsekämpfung in Böden 1996; (1): 81. [13] Sartorato I, Zanin G, Baldoin C and Zanhe C. Oservations on the potential of mirowaves for weed ontrol. Weed Researh 006; 46(1): [14] Brodie G. The influene of load geometry on temperature distriution during mirowave heating. Transations of the Amerian Soiety of Agriultural and Biologial Engineers 008; 51(4): [15] Cronin NJ. Mirowave and Optial Waveguides. J W Arrowsmith Ltd: Bristol [16] Nikolova NK. Modern Antennas in Wireless Teleommuniations. (aessed 5th of August, 013). [17] Velazquez-Marti B, Graia-Lopez C and Plaza-Gonzalez PJ. Determination of dieletri properties of agriultural soil. Biosystems Engineering 005; 91(1): [18] Von Hippel AR. Dieletri Materials and Appliations. M.I.T. Press: Camridge [19] Shen JB, Xu LY, Jin XQ, Chen JH and Lu HF. Effet of temperature regime on germination of seed of perennial ryegrass (Lolium perenne). Grass and Forage Siene 008; 63(): [0] Brodie G, Jao MV, Sheehan M, Yin L, Cushion M and Harris G. Mirowave modifiation of sugar ane to enhane juie extration during milling. Journal of Mirowave Power and Eletromagneti Energy 011; 45(4): Reeived on Aepted on Pulished on DOI: Brodie and Hollins; Avanti Pulishers. This is an open aess artile liensed under the terms of the Creative Commons Attriution Non-Commerial Liense ( whih permits unrestrited, non-ommerial use, distriution and reprodution in any medium, provided the work is properly ited.

10 Minerva Aess is the Institutional Repository of The University of Melourne Author/s: Brodie, G; Hollins, E Title: The Effet of Mirowave Treatment on Ryegrass and Wild Radish Plants and Seeds Date: Citation: Brodie, G; Hollins, E, The Effet of Mirowave Treatment on Ryegrass and Wild Radish Plants and Seeds, Gloal Journal of Agriultural Innovation, Researh & Development, 015, (1), pp Persistent Link: File Desription: Pulished version