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 7614 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 and maintain, and is more prone to blockages of trash. Sowing rates Rice should not be sown at rates higher than 150 kg/ha for any variety or sowing method. To establish 200 plants/m2 at a seed establishment of 40% requires a maximum sowing rate of 150 kg/ha. If the establishment at 150 kg/ha is as low as 20% there will still be 100 plants/m2 established, which is sufficient to achieve maximum grain yield when best management practice is adhered to. Recommended sowing rates for rice varieties based on seed size and establishment percentage are presented in Table 4. Increasing sowing rates to compensate for poor field layout, unsatisfactory seedbed preparation or unreliable sowing method is rarely successful at increasing plant population and not recommended. Sowing method The broadcasting (spreading) of dry seed onto the soil surface and then applying permanent water to the field led to poor plant establishment in many experiments and is not a recommended sowing method. If dry broadcasting of seed is going to be practiced, the field must be flushed and then drained to allow the seed to access oxygen before permanent water is applied. The significant economic and practical benefit of drill sowing compared with aerial sowing methods has been highlighted in this research. With water being such a valuable resource, it is critical that establishment is well managed or water productivity and crop profitability will be reduced. Drill sowing not only uses less water than aerial sowing but the losses in both input costs and amount of water used are significantly less if establishment is poor and it is necessary to abandon the crop. Future research Research into varietal differences in seed establishment percentage and establishment vigour will be continued so that sowing rates recommendations can be fine-tuned for all current varieties and provided for new varieties as they are released. RIRDC Project PRJ-008764 Influence of plant population on rice growth and grain yield Acknowledgements This research was funded by the Rural Industries Research and Development Corporation and NSW Department of Primary Industries. Further information Brian Dunn Research Agronomist T: 02 6951 2621 E: [email protected] l Aerial sown density experiment showing the very high plant population where the seed was pre-germinated compared to the very low density where seed was spread on the soil surface prior to permanent water. l Collecting PI samples from the YAI drill sown variety by density experiment in 2015–16 season. 0 2 4 6 8 10 12 14 16 18 0 100 200 300 400 500 600 700 Grain yield (t/ha @ 14% moisture) Plant population (plants/m2) 10 12 14 16 18 14% moisture) IREC Farmers’ Newsletter — Large Area No. 195: Rice R&D 2016 1 0 2 4 6 8 10 12 14 16 18 0 100 200 300 400 500 600 700 Grain yield (t/ha @ 14% moisture) Plant population (plants/m2) y = 4.944x0.2361 R² = 0.3138 0 2 4 6 8 10 12 14 16 18 0 10 20 30 40 Grain yield (t/ha @ 14% moisture) Plant population (plants/m2) Plant population (plants/m2 ) Grain yield (t/ha @ 14% moisture) Grain yield (t/ha @ 14% moisture) Plant population (plants/m2 ) y = 4.944x0.2361 R² = 0.3138 Figure 2. Grain yield obtained from all experiments at plant populations less than 40 plants/m2 . Figure 1. Grain yield obtained at different plant populations from 808 aerial and drill sown plots in the project, across all sites and seasons. Red squares are average of 25 data points.