Take home messages

• The Hyper Yielding Crops (HYC) project is a GRDC national investment which aims to push the economically attainable yield boundaries of wheat, barley and canola across five states.
• Spring sown barley, sown on 1 September in northern Tasmania averaged 10t/ha yields and an experimental line from Europe - Laureate – yielded 11.42t/ha which has set a new yield benchmark for barley.
• Spring sown barley yielded higher than spring sown wheat in 2020.
• Variety maturity rankings from autumn plantings do not reflect responses from spring planting dates due to day length. Varieties that developed slower under long days were higher yielding.
• The yield constraints to spring sown barley are consistent with autumn sown, however the agronomic management levers differ in timing and intensity.
• High spring sown barley yields can be achieved by applying fungicides at lower label rates from growth stage 30 to 39.
• Hyper yielding cereal crops cannot be produced with artificial fertiliser alone; N applications are more likely to influence protein than yield on fertile soils.

Background

The HYC project is a Grains Research & Development Corporation (GRDC) national investment which aims to push the economically attainable yield boundaries of wheat, barley and canola across five states. Through this four-year investment, high yield potential cultivars suited to local environments will be identified and the most appropriate agronomic management tactics including paddock selection and preparation, canopy management, disease, weed and pest control, and crop nutrition strategies will be explored to assist grower and adviser decision making. The 2020 experiments hosted at FAR Australia’s Tasmania crop technology centre (Hagley) focused on irrigated barley emerging in spring rather than autumn. Most of the common yield constraints to spring sown barley are consistent with autumn sown situations. However, the management solutions required to address them differ in both timing and intensity and will be highlighted using key results from the 2020 HYC trial program. The experiments hosted at the Tasmania crop technology centre were sown on 1 September 2020; 310 millimetres of rain fell during the growing season from September to January, as well as 80mm of supplementary irrigated water applied.

Spring sown barley versus autumn sown cereals

Much of the focus of improving cereal productivity in recent years has been sowing slower developing germplasm earlier. However, unlike wheat, this system has not yet delivered the expected yield gains for barley in the higher rainfall areas. Currently the quicker developing spring barley varieties suited to low and medium rainfall zones such as Rosalind and RGT Planet are also the highest yielding in the higher rainfall zones irrespective of their sowing date. The record yields achieved from spring planting in 2020 highlight spring-sown barley as another high-yielding sequencing option. In a management trial at FAR Australia’s Tasmania crop technology centre in 2020 spring sown RGT Planet yielded 9.59t/ha and Rosalind 8.29t/ha, whereas the spring wheat Trojan yielded 8.79t/ha. Spring barley is yielding higher than spring wheat at this sowing date, this is contrary to autumn planted crops where wheat yields are generally greater than that of barley.

The climatic conditions for spring sown barley are more favourable in Tasmania compared to other regions of Australia and may be a more profitable farming system than autumn sown barley. Other benefits include its suitability in the rotation of diverse Tasmanian farming systems. For example, spring planted barley can be grown as a summer crop that is harvested in January or February. This means there is opportunity to grow another crop, such as autumn-sown fodder. There are some major climatic differences that will influence management and germplasm decisions. The obvious climatic differences between autumn/winter sown and spring sown barley are temperature, day length and rainfall patterns (figure 1). Incoming solar radiation also increases with day length.

Figure 1. Schematic comparison of crop life cycle, vegetative (V), Stem elongation to flowering (SE-F), and grain filling in spring barley sown in autumn and spring. The mean max temperatures (●) and mean minimum temperatures (○) and shaded area represent the daylength (hrs) at Hagley Tasmania.

Crop development and yield

The relationship between crop development and yield is different for spring sown barley. Spring sown barley has a much shorter life cycle. This has implications for yield development and crop management.

• Spring sown barley is sown into increasing daylength and temperatures, and thus crop development is typically a lot faster. The growing season, (particularly the vegetative phase) is reduced relative to autumn and winter sown crops (figure 1) This has implications for yield development, seeding rates and timing of fungicide applications.
• The critical period for grain number development occurs under different climatic conditions. Increased solar radiation during this period has the potential to increase yield potential if water is non limiting. However, flowering and thus grain filling is likely to occur later than optimal and may be exposed to a greater heat stress risk than autumn sown barley. This will require cultivars that can maintain grain weight under these conditions.

Implications for variety choice

Variety maturity rankings from autumn plantings will not reflect responses from spring planting dates. Varieties differ in development speed and the way they respond to changes in daylength and temperature. Australian breeders have selected germplasm that is adapted for autumn sowing in the lower rainfall zones that have an ability to develop faster under warm temperatures and increasing daylength. In very sensitive varieties, as the days lengthen, the crop requires fewer degree days to flower. Thus a delay in sowing date (i.e. spring planting) will result in a reduction in the duration of the sowing to flowering period because of an increase in mean temperature, as well as in mean photoperiod (figure 1). Very photoperiod sensitive varieties are unlikely to be suited to spring planting because they will develop too quickly during the critical periods for yield formation.

Matching variety to environment

Photoperiod insensitive varieties were higher yielding under spring sown conditions. The HYC program evaluated 25 different germplasm including Australian controls, Australian breeding lines and European material for their development and adaptation to spring sowing in 2020. Previous results from the FAR Australia led GRDC HYC Project in Tasmania demonstrated that the optimum flowering time for wheat yields was from 17 October – 7 November. Our 2020 results showed that European derived barley germplasm, with less sensitivity to photoperiod (day length) achieved the highest yields despite only just finishing stem elongation (Zadok growth stage 37) during this period (first week of November), whereas quicker Australian material such as Rosalind and Fathom that began to flower in this period were lower yielding (figure 2).

Figure 2. Relationship between Zadok growth stage during the optimal flowering period (3 November) and grain yield in spring sown barley at Hagley, Tasmania 2020 (line = LSD at 95% level of significance).

Variety yield potential

Yields achieved at FAR Australia’s Tasmania crop technology centre were the highest across the Hyper Yielding Crops (HYC) program (Table 1) and demonstrated the yield potential and adaptation of barley to spring sown conditions in Tasmania. The highest yielding spring cultivar in this experiment was Laureate at 11.42t/ha. The quick spring cultivar control Rosalind yielded 9.27 t/ha while RGT Planet yielded 10.43t/ha. The long sunny days and cool grain fill conditions allowed for greater biomass accumulation and maintenance of grain weight. Alestar, Fathom, IGB1844, Laperouse, Rosalind and other photoperiod responsive cultivars yielded significantly lower (less than 9.5t/ha) than the cultivars without a strong photoperiod requirement such as RGT Planet, Laureate, HV8 Nitro, and the experimental AGTB0244 line. These results can be found at FAR website.

Table 1. Grain yield (t/ha) of the relevant spring controls and best performing introduced or alternate spring, 2 row winter and 6 row winter varieties at each crop technology centre (CTC). Shaded treatments within a site are statistically the highest yielding treatments for the site.

¹sites received one PGR, ² sites received 2 PGR.

What about earlier sown barley?

Earlier sowing, slower developing barley are one potential avenue to increase grain yield in barley. Winter cultivars are slower to develop due to vernalisation. Vernalisation is the requirement by which exposure to low temperature (between 0 – 15C) progresses crop development. Spring barley cultivars typically have little to no vernalisation responses. The cooler temperatures between May and August are generally enough to satisfy any vernalisation requirement in Tasmania, however later plantings will take much longer to satisfy their vernal requirements and flowering would occur under suboptimal conditions. Cultivars with a strong vernalisation requirement are unlikely to be suited to spring planting. Evaluation on the yield response of early sown winter cultivars is being conducted at other HYC research sites across South Australia (SA), Victoria (VIC), and Western Australia (WA). In 2020, six row winter barley was introduced to Australia and evaluated in yield plots for the first-time. In these experiments the highest yielding two and six row winter barley were comparable with the spring barley control RGT Planet in VIC but not at any other sites, this was due to head loss and lodging in SA, and flowering too late and thus heat and drought stress in WA (table 1).

The experimental six row winter experimental line Pixel was the most consistent performer and will progress to management trials in 2021. RGT Planet and Rosalind remain among the highest yielding cultivars across all centres and are broadly adapted despite flowering earlier than most other cultivars and remain the benchmarks in adaptation and yield performance. The spring sown outcomes achieved in Tasmania with the cultivar Laureate at 11.4 t/ha becomes the benchmark yield for the remainder of the project.

Disease management

Since the growing season is shorter and crops develop faster, spring sowing has the added advantage of reducing disease pressure and lodging which, in turn, reduces expenditure on fungicide and plant growth regulators (PGRs). These results need to be evaluated across multiple seasons, however the first year of trials at the Hagley site demonstrated that high spring sown barley yields, by applying fungicides at lower label rates from growth stage 30 to 39 in susceptible cultivars RGT Planet and HV8 Nitro can be achieved (Table 2). In contrast, autumn sown RGT Planet in other experiments has required more robust fungicide strategies to control disease pressure over the longer season.

Table 2. Influence of disease management strategy and variety of barley grain yield (t/ha) in spring sown barley at Hagley, Tasmania 2020.

*Note Aviator Xpro® label states do not apply after Z45

Nutrition

Despite achieving high yields, there were limited yield responses recorded to applied nitrogen (N) in the 2020 HYC results, however protein increases were observed. For example, at Millicent in 2020, despite grain protein levels being below 10%, there wasn’t any additional yield benefit from an extra 25% and 50% of applied N compared to the standard practice of 130kg N/ha (Table 3). This is a recurring trend with all high yielding experiments, irrespective of sowing date and would suggest high fertility soils fuelled by improved crop rotations rather than applied fertiliser is the pathway to achieve yields greater than 10t/ha. When applying N, the spring-planted trials demonstrated growers can apply more of the crop’s nitrogen requirements early in the growing season without negatively impacting yield and achieve lower protein levels for malting. N applied later than stem elongation increased grain protein above malt requirements.

Table 3. Mean yield and protein responses to extra applied Nitrogen (N) and Sulfur (S) at Gnarwarre, VIC and Millicent, SA in 2020

*All treatments had 100kg/ha MAP, standard practice = 148kgN/ha at Gnarwarre, and 130kgN/ha at Millicent

Conclusion

These results are part of a broader GRDC HYC project and help to determine whether growers have the correct genetic and management tools to reliably achieve high yields in all regions of the southern high rainfall zone (HRZ). The results so far demonstrate date germplasm selection, disease control, and high inherent fertility are the foundations of high yielding systems. Growers seeking more information or detail about the HYC experiments are encouraged to visit the FAR Australia website results: HYC Project 2020 Results Barley Final

Acknowledgements

The research undertaken as part of this HYC project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC. The authors would like to thank them for their continued support. Field Applied Research (FAR) Australia gratefully acknowledges the support of all of its research and extension partners in the HYC project. These are CSIRO, the Department of Primary Industries and Regional Development (DPIRD) in WA, SA Research and Development Institute (SARDI), Brill Ag, Southern Farming Systems (SFS), Techcrop, the Centre for eResearch and Digital Innovation (CeRDI) at Federation University Australia, MacKillop Farm Management Group (MFMG), Riverine Plains Inc and Stirling to Coast Farmers.

Useful resources

FAR Australia website Barley results: HYC Project 2020 Results Barley Final.

Hyper Yielding Crops podcast

Hyper Yielding Crops YouTube

Hyper Yielding Crops podcast

HYC Provisional 2020 Wheat Results

HYC Provisional 2020 Canola Results

Contact details

Kenton Porker
Field Applied Research (FAR) Australia
Shed 2/ 63 Holder Road, Bannockburn, Victoria 3331
0403 617 501
Kenton.porker@faraustralia.com.au
@kentonp_ag
@far_australia