Ground Cover Supplement : GC Supplement - Tactical cereal agronomy
14 Irrigated cereals TACTICAL MANAGEMENT FOR LODGING By Dr Allan Peake IRRIGATED WHEAT HAS become increasingly popular across the northern grains region due to fluctuations in water availability and commodity prices. The yield potential of irrigated wheat varies from about seven to eight tonnes per hectare in Central Queensland to more than 10t/ha in southern New South Wales, although even under irrigation the yield potential will fluctuate between seasons. Unfortunately, wheat crops become increasingly prone to lodging as yields increase above 6t/ha. While moderate lodging causes inconvenience at harvest, it can also reduce yield by interfering with crop growth processes such as water uptake VARIETY SETS IRRIGATED WHEAT YIELD There is substantial potential for increased production and profitability of irrigated cereals By Tony Napier and Deb Slinger IRRIGATED WHEAT HAS the potential to consistently yield more than 10 tonnes per hectare with optimum management but growers are often achieving much lower yields than this. The best-performing dryland wheat varieties may not be as successful in irrigated systems. Identifying the best wheat varieties and agronomic management for irrigated systems is essential for achieving consistently high yields. We investigated the barriers to achieving consistent 10t/ha yields for irrigated wheat in trials across south-east Australia. Located at Leeton and Coleambally in the New South Wales Riverina, the trials evaluated the effect of variety, plant population and nitrogen management on grain yield and grain quality. Plant populations were low (140 plants per square metre) or high (210 plants/m2). GRAIN YIELD Variety was a major driver of high yields at both irrigated sites, with SuntopA and CharaA in the highest yielding bracket at both trial sites. LongReach LancerA and KioraA also performed well, both achieving high grain yield at both sites, while MaceA, LongReach DartA and EGA GregoryA had the lowest yields at both trial sites (Figure 1). Grain yields at Coleambally were significantly lower than Leeton, likely because of less available moisture due to irrigation scheduling. The Leeton site received 2.2 megalitres/ha during pre- watering in autumn while Coleambally received only 1.2ML/ha. Leeton received an additional three spring irrigations (total of 5.5ML/ha for the season) and Coleambally two spring irrigations (total of 3.8ML/ha for the season). At Leeton six of the 12 varieties included in the trial achieved more than 10t/ha, with SuntopA and CharaA both yielding 10.32t/ ha followed by KioraA, MerindaA, CorackA and LongReach LancerA (Figure 1). At Coleambally, SuntopA (7.3t/ha) was again the highest-yielding variety, followed by LongReach LancerA and CharaA. EGA GregoryA yielded the least at Leeton (8.84t/ ha) followed by MaceA (9.05t/ha) and LongReach DartA (9.53t/ha). The three lowest-yielding varieties at Coleambally were LongReach DartA (5.86t/ha), BolacA (6.60t/ha) and EGA GregoryA (6.72t/ha). At Leeton a plant population of 140 PHOTO: DEB SLINGER NSW research is investigating the barriers to achieving consistent 10t/ha yields for irrigated wheat in trials across south-east Australia. The wheat varieties SuntopA and CharaA were consistent high yielders (7 to 10t/ha) across two NSW irrigated wheat trial sites. FAST FACTS and light interception. Mild lodging that starts shortly before harvest can simply be a sign of a high-yielding crop, while lodging that occurs soon after flowering is more likely to cause yield loss. Avoiding lodging requires a package of tactical management options, including variety selection, management of soil and fertiliser nitrogen, seeding rates, irrigation strategies and plant growth regulators. However, it is important to realise that a well-managed crop can still lodge in severe storms, while susceptible crops might avoid lodging if they experience mild weather conditions during grain filling. VARIETY CHOICE In the 2008 season when widespread lodging occurred, many growers were using their favoured dryland varieties in irrigated fields. Unfortunately, many of these varieties have since been shown to be susceptible to lodging (for example, BaxterA, StrzeleckiA, Sunco, EGA BurkeA, EGA GregoryA) and are not recommended for fully irrigated production fields. Recent experimentation has identified a range of fast-maturing and longer-season varieties that have good lodging resistance in Queensland and northern NSW. Varieties such as LongReach TrojanA, LongReach CobraA, LongReach LancerA, MitchA, LongReach CrusaderA, SuntopA and WallupA have generally performed well in our irrigated experiments. Growers should note that all of these varieties have been observed to lodge under severe conditions. However, they are less likely to lodge than other more susceptible varieties. NITROGEN The first step in nitrogen management for irrigated wheat is to obtain soil nitrogen test results to a depth of at least 90 centimetres well in advance of sowing. Crops started with about 70 to 90 kilograms/ha of nitrogen (that is soil plus fertiliser nitrogen at sowing) can avoid the excessive crop growth during tillering that has been associated with increased lodging risk.
GC Supplement - Grain storage 2015
GC Supplement - Spray application 2016