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 7627 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 An area of 73.5 m2 was excavated and manually levelled into a turkey-nest pond so the area could be flood irrigated to grow rice. The experiment consisted of two treatments: untreated control (T0) plots and microwave treated (T1) plots. The individual 2.0 x 2.0 m plots were laid out with a 0.5 m untreated buffer zone between each plot, as shown in Figure 1. The soil of the microwave treated plots (T1) was irradiated using two horn antennae (see picture) with internal dimensions of 110 x 55 mm, which were separately attached to two domestic microwave ovens (EMS8586V; Sanyo; Tokyo, Japan) operating at 600 W with a frequency of 2.45 GHz. The applied microwave energy density in the treated plots was approximately 730 J/cm2 . The soil was watered to field capacity prior to microwave treatment to allow better heating in the soil. Infrared thermal images, captured with an infrared camera (C2; FLIR Systems Inc; Wilsonville, Oregon, USA) immediately after treatment of the area under the horn confirmed that the soil temperature exceeded 80°C (Figure 2). The experimental plot was flooded to a depth of 5 cm and seed of the rice variety Opus was broadcasted by hand at a seeding rate of approximately 125 kg/ha. Phosphorus (80 kg P/ha), potassium (60 kg K/ha) and zinc (4 kg Zn/ha) were applied to the entire experimental area at the time of sowing. Three split doses of nitrogen, equivalent to a total rate of 120 kg N/ha, were applied during the growing season. Netting was fixed over the experimental plot to reduce bird scavenging during the early stages of development. An infrared gas analyser (LI-6400XT; LI- COR Inc; Lincoln, Nebraska USA) was used to measure the physiological parameters of rice at maximum tillering. Number of tillers, fresh biomass and dry biomass were measured for a randomly selected 0.09 m2 quadrat drawn from each of the plots. Weed population was counted for each experimental plot. Grain yield, fresh above ground biomass, dry above ground biomass, tiller density, weed numbers and weed biomass were all assessed at harvest time. Statistical analysis using analysis of variance (ANOVA) was undertaken. Rice growth after microwave Microwave irradiation of soil reduced weed emergence in the treated plots by 81%. The main species of weeds found in the plots were: hairy panic grass (Panicum effusum), barnyard grass (Echinochloa colona), and dirty Dora (Cyperus difformis). l Figure 1. Experimental layout of the two microwave treatments, untreated control (T0) and microwave treated (T1), of the rice field experiment located at Dookie College Campus, The University of Melbourne, Victoria in 2015–16. l Figure 2. Infrared thermal image of the microwave heating pattern of the soil in field conditions for the rice experiment. The temperature in degrees Celsius (°C) of the soil is indicated by colour, according to the temperature scale on the right hand side of the image. Table 1. Assessment of key rice crop growth parameters for microwave treated soil experiment Measured parameter Treatments LSD5% % Change from Microwave Control control treated  Fresh weight at panicle formation stage (g/quadrat) 416.8a 225.5b 116.3 85%  Dry weight at panicle formation stage (g/quadrat) 91.3a 50.8b 26.1 80%  Tiller density at panicle formation stage (number/quadrat) 104.0a 61.5b 32.2 69% Chlorophyll content 42.3 43.6 3.3 -3% Leaf area index 4.0 2.6 1.5 56%  Fresh total biomass weight at harvest (t/ha) 64.2 57.0 13.1 13%  Dry total biomass at harvest (t/ha) 31.1a 25.6b 4.2 22% Grain yield at harvest (t/ha) 10.1a 7.5b 2.0 35%  Tiller density at harvest (number/quadrat) 419a 292b 113.9 43% Weed density (number/ha) 44,000a 237,000b 94.3 -81% Weed biomass dry matter (kg/ha) 54.0a 306.5b 174.0 -82% (Note: means with different superscripts on the same line are significantly different from one another) Replicate 1 Replicate 2 Replicate 3 Replicate 4 Replicate 5 Buffer Zone 0.5m Buffer Zone 0.5m Buffer Zone 0.5m Buffer Zone 0.5m Buffer Zone 0.5m 0.5m T0 T1 T1 T0 T0 T1 T1 T1 T0 T0 0.5m 0.5m 0.5m 0.5m