Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 7628 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 The average weed density in the untreated control plots was equivalent to 237,000 plants per hectare; and the average weed density in the microwave treated plots was equivalent to 44,000 plants per hectare (Table 1). Many of the weeds in the microwave treated plots were hairy panic grass, which may have invaded the plots later in the season. Microwave treatment also enhanced many of the growth parameters of rice including the tiller density, crop dry weight and grain yield (Table 1). Some of these parameters were visually evident as shown in the photos on page 26. However, no significant difference was observed in chlorophyll content or leaf area index (Table 1). The higher biomass and tiller numbers at panicle formation stage suggested that the rice plants growing in the microwave treated soil matured faster than those in the untreated soil; however, there was some compensatory growth in the untreated plots later in the season, as indicated by the reduced differences in biomass and tiller numbers at harvest. The faster maturation of the crop in the microwave treated plots was also observed in the difference in ripeness of grains near to harvest time. It was also observed in the difference in moisture content of the harvest biomass, with the mean moisture content of the biomass from the microwave treated plots being 131% (on a dry weight basis) and the mean moisture content of the biomass from the control plots being 150%. Conclusion This trial demonstrated significant reductions in weed emergence during the cropping period due to pre-treatment of the soil with microwave energy. Significant yield increases were also achieved from microwave pre-treatment in this trial. This research has also demonstrated that microwave soil treatment provides multiple benefits for rice production. Its immediate effect is to reduce weed emergence; however, it also enhances plant growth and crop yield. Field experiments and small trials are planned for the coming season to further verify the potential of this technology, with the hope of a semi-commercial prototype system for lager field trials being developed in the near future. RIRDC Project PRJ-008765 A study of microwave-based weed management in the rice industry Further information Graham Brodie T: 03 5833 9273 E: [email protected] l Prototype two horn antennae microwave system operated through two 2.45 GHz domestic microwave ovens to irradiate soil under field conditions.