23 IREC Farmers' Newsletter No. 198 — Spring 2017 3. Reduced barnyard grass Check: Choose paddocks and winter crop rotations with lower barnyard grass seed banks. There is no perfect way of reducing barnyard grass, so avoid paddocks with too much to start with. Barriers: A history of high barnyard grass is a barrier to delayed permanent water. A lot of winter crop paddocks still have a seed burden from barnyard grass growing in summer. With tighter rice rotations and selection of lower water use paddocks, rice may be reduced to 25% of the farm area. This means it is harder to choose low barnyard grass paddocks, resulting in less winter crop in the rotation. Ordram® is still the best control of barnyard grass in aerial sowing. 4. Earlier sowing Check: Earlier sowing is required for delayed permanent water because there is moisture stress between flushes, which will delay the rice growth. This can be overcome a little by sowing crops with later recommended sowing dates, such as Sherpap , YRK5 and YRM70. Barriers: Sowing earlier means that it is cooler, which may limit rice vigour at establishment. The Murray Valley is 1–2 °C cooler than the MIA. Early sowing can be hindered by wet conditions as occurred this last sowing season. It’s a matter of being patient. 5. Controlled late BYG germinations Check: Late barnyard grass germinations must be controlled, ideally with BarnstormTM and Aura®, which require the soil surface to be very wet but with no surface water. Spraying before sunrise is best. If it is too hot, as often happens in late November/early December, the ground will dry out quickly and a high water rate is needed when spraying. Some farmers claim better results using a helicopter. Barrier: Barnstorm and Aura do not work consistently. When the soil is wet, it is hard to get a ground rig on. Some farmers say the cost of Magister® and Stomp® at $110/ha plus Barnstorm at $130/ha is too high. Delaying the permanent water further, increases the chance of more weed germinations. 6. Water management Check: When flushing, use flume gates that allow water on and water off faster, ideally watering with 25 ML per day. Barrier: Avoid moisture stress to the crop, as it slows growth and development. However, there may be supply constraints if everyone on the supply channel decides to fill at about the same time. 7. Water savings less than research results Check: Normal drill sowing with two flushes (the first a soaking) will be sufficient for crop emergence. Delay permanent water until rice is 10–15 cm tall in late November/early December. The rice will be stressed but this will save water and not delay rice too much. Barrier: Unlike small research plots, farmers may not be able to recycle irrigation drainage, which can push up water use for delayed permanent water. There is always loss from seepage and ET with reirculated water, so water recovery is not 100%. There is not much difference between slightly delayed permanent water and delayed permanent water three weeks later. Reported water savings in practice are only 1 ML/ha, less than the 2.2 ML/ha showed by research results. Note, this year’s results showed a 1.4 ML difference. 8. Labour clash Check: Delayed permanent water is best suited to small paddocks or farms where there are only one or two paddocks of rice, so farmers have time to supply the required labour. Barriers: Many growers do not have the manpower for delayed permanent water if sowing several paddocks. Some do not own spraying gear and may not be able to obtain a contractor at the right time, therefore aerial sowing is easier. Spraying in late Nov./early Dec. or flushing can clash with winter crop harvesting and sheep work. Generally, ducks are not a problem with aerial sowing but wind can be. Normal drill has no ducks or snails, allowing two flushes and permanent water before winter crop harvest. Rice crops near creeks and rivers have the main duck issues. Aerial sowing uses less labour, so timing of practices is better. Rice harvest later in the autumn is more likely with delayed permanent water and clashes with April canola sowing. 9. Gross margin/ML There is a need to compare costs and gross margin per megalitre of delayed permanent water with drill or aerial sowing. Further information John Lacy T: 0427 311 821 E: [email protected] With quality branded products & local experienced agronomy teams delivering a broad range of on-farm services and advice. Adrian Hayes 0428 696 008 James Kanaley 0408 692 310 David King 0428 635 340 James Codemo 0428 570 395 Allan Tonacia 0475 960 232 Alan Murnane 0427 561 806 AGnVET Services has the Expertise & Reliability you can count on For the expertise and reliability you can count on contact your local AGnVET agronomy specialist