7 IREC Farmers' Newsletter No. 199 — Autumn 2018 Mulching of rice straw after harvest, in preparation for sowing wheat. PHOTO: Neil Bull RGA Paddock selection When growing wheat after rice it is important to first consider: is the paddock suitable? If the paddock does not have good surface drainage then do not sow it to wheat straight after rice. Paddock layout is also important and will need to be laser graded and designed to ensure good drainage. Refer to the list of ‘Don’ts’ for unsuitable layout types for wheat after rice. Rice stubble management In paddocks that are suitable for double cropping, it is important that rice stubble is removed as soon as possible after harvest, to allow the soil to warm and dry. Mulching and burning is the quickest method of stubble removal to minimise turnaround time. Other options for stubble removal include mowing stubble and burning or baling but this will add time and delay sowing. New technology and equipment than can be used on wider row spacings do make inter- row sowing into standing rice stubble possible, however a burn is still needed to remove the most of the stubble to ensure that light can get to the establishing crop. DOs Paddock selection • Only select paddocks that have good surface drainage • Have clean toe furrows and drains In the rice phase •  Consider drill sowing to minimise the risk of lodging and for easier stubble handling •  Sow on time to ensure draining and harvest occur as early as possible •  Drain at the right time so bays are dry enough to avoid wheel ruts at harvest •  Use straw spreaders on the rice header to distribute trash evenly In the wheat phase • Sow early, preferably before the end of April • Use a higher than normal seed rate •  Use higher than normal fertiliser rates and top dress nitrogen early DON’Ts Paddock selection • Don’t select paddocks with poor surface drainage • Avoid paddocks with the following layouts: • contour bays with slopes less than 1:2000 • flat, terraced bays without beds • Avoid paddocks that: •  are not laser graded or need re-grading because of reverse grades •  have known poor field drainage, such as old style, “natural” contour bays In the wheat phase •  Do not sow after 7 May in the eastern Murray Valley or after 14 May in the western Murray Valley and Murrumbidgee Valley Introducing Alex Schultz Alex is a Research & Development Officer – Water Productivity with NSW Department of Primary Industries (DPI) based at Deniliquin. Alex, who grew up on an irrigation farm in the southern Riverina, has worked as a commercial agronomist and a water trader. Most recently, Alex was a project officer for two projects: the GRDC funded Soils under an irrigated environment and the CRDC-funded Maximising on-farm irrigation profitability – southern connected systems. As Research & Development Officer – Water Productivity, Alex will identify and develop priority and emerging irrigated agricultural research issues, relevant to the needs of the southern NSW irrigated agricultural industries. Sowing Unfavourable soil conditions after rice can cause lower than average establishment and tillering percentages in wheat. Sowing seed at higher rates (100–140 kg/ha) is recommended to achieve tiller densities of 350–550 tillers/m² for a yield potential of 5.0 t/ha or more. Sowing into warm soil that is not saturated is important to encourage good early season growth and tillering. It is recommended to sow as early as possible after 25 April because later in the sowing window soil temperature drops and the chance of rainfall increases. The cut-off point for sowing wheat after rice is considered to be 14 May. At this point the paddock should be left fallow and sowing efforts focused elsewhere on the farm. A cut-off date of 7 May is best for the eastern Murray Valley because of cooler, wetter conditions in that district. Varieties Seek advice from an agronomist when selecting a variety. High protein can be difficult to achieve in wheat crops after rice, so the focus should be on yield and not protein. Sowing a mid-season biscuit variety (low protein soft wheat) with high-tillering characteristics is recommended. Additionally, rice soils are often acidic so an acid tolerant variety should be considered if soil pH (measured in CaCl2 ) is below 5.0. An acid tolerant variety is highly recommended if soil pH is below 4.5.