Closing the economic yield gap for grain legumes in WA
Key Messages
- Higher legume yields may be achieved with narrow row (25mm) spacing, compared to a wide row spacing (50mm).
- PBA Bendoc faba beans can significantly outyield PBA Amberley faba beans.
- The improved disease rating in PBA Amberley may not decrease disease loading in a high-pressure environment or translate to yield improvement (in comparison with PBA Bendoc).
- PBA Bendoc faba beans yielded higher than lupins when sown in April but lupins outyielded both varieties of faba beans at a later time of sowing (June).
- Faba bean seeding rates as low as 120 kg/ha can still result in more than 20 plants/m2 (20-25 recommended) and do not impact on grain yield compared to a higher seeding rate (180 kg/ha).
- There was no negative impact of the use acid tolerant rhizobia on plant establishment.
- The use of acid tolerant rhizobia had a significant positive impact on faba bean biomass production – approximately 750 kg/ha increase as at mid-September.
- Early sowing (mid April) consistently produced the highest faba bean yields across both trial sites.
- Yield declined sharply when sowing was delayed into late May, regardless of variety.
- Early harvest (November) decreased yield by up to ~0.9t/ha compared with the more standard December harvest timing.
- The $40/t early harvest premium generally did not compensate for yield penalties associated with early harvest.
- Maximising season length through early sowing and full maturity harvest delivered the highest gross margins.
Resources
THE LARGER PROJECT
This comprehensive project will combine extension, trials, technical and economic analysis to support growers to access the benefits of legumes in crop rotations moving forward.
Established as a project with investment by the GRDC, GGA will collaborate with government, agribusiness, researchers, grower groups and growers to address the low adoption of grain legumes in WA farming systems.
Origins of the project stem from GRDC analysis indicating farmers are aware of the benefits of legumes in crop rotations but concerns around pulse reliability, profitability and lack of confidence in their consistent production are causing barriers to integration. Consequently, Western Australian farmers have been slow to exploit the recent advances in grain legume genetics, acid-tolerant rhizobia, management strategies, weed and disease protection products.
Combatting this situation requires an extensive technical and extension program to change grower sentiment, driving new capabilities into profitable cropping systems. The project will see collaboration between government, agribusiness, researchers and end-users to address the current poor rate of adoption of grain legumes in WA farming systems.
2022 – TIME OF SOWING, ROW SPACING, AND DISEASE RESISTANCE
Faba beans are the preferred pulse crop in the Frankland River/Tenterden region because they have the greatest waterlogging tolerance. Many growers are replacing lupin hectares with faba beans because they are more profitable. Lupins were added to the trial design to allow SCF to compare the productivity and profitability of the two pulse crops in the trial.
Faba beans require more protection from disease than any other common broad-acre crops grown in Western Australia (WA). In 2021, local Frankland farmers recorded up to five different fungicide applications during the season to protect faba beans from chocolate spot, Botrytis fabae. Local growers and advisors wanted to know if sowing later lowers the disease pressure and reduces the number of fungicide applications.
The small plot trial looked at the interaction between row spacing, disease levels and sowing times. The wider the row, the lower humidity is, which means the causal agent of Chocolate Spot (Botrytis fabae) is less likely to infect faba bean plants successfully. However, most growers have 25-30cm row spacings in WA to suit other crops (wheat, barley and canola) and need considerable motivation to sow faba beans with wider spacings. A small number of WA growers have separate seeders to plant faba beans at wider spacings, but it is not common practice.
A current limitation to growing faba beans is the detrimental impact of soil acidity on nodulation. Research shows that when commercial inoculants for faba beans are used, nodulation decreases rapidly below pH 6 to almost negligible at pH 4. A rhizobium strain has been developed by SARDI that has increased tolerance to soil acidity. This strain is likely to be commercially available in 2024.
This trial aims to compare the nodulation and productivity of faba beans grown in acidic soil (pH 4.8) using the new acid tolerant inoculant (SARDI) for faba beans, standard group E/F inoculant at a single rate and this inoculant at a double rate. In addition, the productivity of the faba beans in the demonstration will be compared to a surrounding paddock of lupins.
2025 – OPTIMISING SOWING & HARVEST TIMING IN FABA BEANS TO ACCESS EARLY-HARVEST GRAIN PREMIUMS
Faba bean area in the HIgh Rainfall Zone (HRZ) of Western Australia has expanded in recent years as growers seek profitable alternatives to lupins on suitable soils and in waterlogging-prone paddocks. However, limited and inconsistent marketing opportunities have historically restricted adoption.
Recent industry collaboration helped establish a direct export pathway for faba beans through the Port of Albany, improving marketing confidence and price transparency for growers. Grain marketers also identified a potential premium of approximately $40/t for beans harvest early (late October – early November) to meet a short-term Egyptian market window.
The 2025 trial aimed to determine whether optimising sowing date and variety selection could allow growers in the South Coast/Lower Great Southern region to harvest faba beans earlier to capture this premium without significantly compromising yield or profitability.
Acknowledgements
This project is led by the Grower Group Alliance with investment from GRDC.
