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 7644 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 rice crop in Cununurra Clay soil was made using a range of measurement systems. The results showed that deep percolation losses were less than 1 mm/day. The estimated total water usage of flooded rice for variety NTR 587 in 2014 was 9.7 ML/ha. Hence undertaking the cultivation of flooded rice systems in similar soil types of Cununurra Clay soil is considered safe and within manageable limits of groundwater recharge rates in the Ord River Irrigation Area. Recommendations Minimum air temperatures of less than 15°C had the biggest impact on varietal performance. Potential cold damage during June and July warrants selection of varieties with cold tolerance for this environment, especially for aerobic growing systems. The flooded rice system is recommended where cold damage is expected and cold sensitive varieties such as NTR 426 and NTR 587 may be grown for their yield advantage. Given ponded water is generally 4–8°C warmer than the air temperature, this system provides some protection against cold damage. Planting dates, varying from late February to late May, were found to play a crucial role for plants to escape potential low temperature damage at critical growth stages. For the flooded system, it appears that a planting date during the second week of May might enable very high yields to be achieved. However, the high amounts (greater than 5%) of chalk in harvested grain due to greater diurnal temperature range during the ripening stages of the crop could be avoided by planting early so that the crop would mature during mild weather. Among the varieties tested, tropical varieties yielded higher than temperate ones. Yunlu 29 was identified as the best variety for an aerobic rice production system in the Ord and Katherine regions. NTR 426 was found to outperform all other tested varieties under the flooded production in the Ord, compared to NTR 587 in Tortilla Flats in the Adelaide River region. Future work is needed with a greater focus on the quality of harvested grain from this region. RIRDC Project No PRJ-00749 Agronomic options for profitable rice-based farming system in northern Australia Further information Dr Siva Sivapalan T: 08 9166 4060 M: 0413 412 937 W: agric.wa.gov.au The response of different rice varieties to an aerobic rice growing system was completely different compared with the response to a flooded system. For economic reasons, it was concluded that varieties could not be broadly adapted to both production systems. Varieties with specific adaptation to each system have been identified for the Ord River Irrigation Area. Overall, varieties originating from tropical regions might be better suited to north western Australia compared with varieties from the temperate regions. Cold air temperatures during the night appeared to be a major issue which will influence the selection of appropriate varieties with cold tolerance. The variety Yunlu 29, from Yunnan Province in China, has red coloured grain and is adapted to aerobic conditions. It has good cold tolerance and remarkable recovery after cold temperature events. It is high yielding (10–12 t/ha) under favourable conditions. It is also believed that rice from this variety could attract premium prices by targeting speciality markets, locally or internationally. Originating from IRRI in the Philippines, the long grain varieties NTR 426 and NTR 587 are believed to have resistance to blast disease. Both varieties have produced good yields up to 10.7–12.5 t/ha in trials under flooded systems. These varieties are very sensitive to cold temperatures and therefore not suited for the aerobic production system. Understanding the amount of leakage under flooded rice fields is becoming more important in the Ord River Irrigation Area as natural resources continue to be developed. An estimation of evaporation, transpiration and deep percolation losses for a flooded at three other sites in the Northern Territory — Katherine Research Station, Tortilla Flats and Coastal Plains Research Station. Among the varieties tested, selected tropical varieties yielded higher than the temperate varieties. Variety Yunlu 29 was identified as the best variety adapted for aerobic rice systems. NTR 426 and NTR 587 were found to out-perform all other tested varieties under the flooded system. Water management Rice is a semi-aquatic plant and considered a heavy user of water. Thus, for the aerobic system, it was necessary to maintain the soil moisture level closer to the drained upper limit to avoid water stress. The results of this project suggested that irrigation scheduling based on a seven-day irrigation interval achieved the best results for the aerobic system in Cununurra Clay soil in the tropical environment. Leakage measurements in the flooded system (Figure 2) revealed that the deep percolation losses in Cununurra Clay soil were either negligible or less than 1 mm/day, which is within acceptable limits of groundwater recharge. The results also indicated that the total water use varied from 9.7 ML/ha for NTR 587 in 2014 to 13 ML/ha for IR 72 in 2013, which is efficient for a rice production system in the tropical environment. Implications The yield performance of temperate and tropical rice varieties tested in this study was influenced by the environmental conditions imposed by factors such as growing season, water management, date of planting and basal and top dressing. l Strip harvesting of rice in the field experiments for yield estimates and quality assessment.