Faba bean for North Central Victoria

Take home messages

• Agronomic and varietal options are now available to profitably produce faba beans, offering growers in North Central Victoria a viable pulse option.
• Choosing the best variety for your environment and farming system will maximise profitability. PBA Bendoc offers an excellent opportunity to control in-season weeds with its improved tolerance to imidazolinone herbicides and sulfonylurea residues. PBA Amberley, with its significantly improved disease resistance and high yield helps reduce cost and risks of production.
• Stubble retention, early sowing combined with good inoculation, nutrition and disease management can secure success for faba beans.

Background

Faba bean has proven to be a profitable and increasingly reliable crop in many farming systems throughout southern Australia, particularly within the medium and high rainfall zones. This is due to the development of adapted varieties (disease resistance and herbicide tolerance) combined with optimised agronomic practices. In 2020, it is estimated that more than 400,000t will be produced off 235,000ha (ABARE 2020), generating more than $500M, inclusive of their farming systems benefits.

There are ongoing opportunities to expand the production area of faba bean and increase its reliability with improved varieties and agronomy. In this paper we provide a short summary of the opportunities for faba bean in the North Central region of Victoria.

Key question 1 - What are some key agronomy factors growers should be focussed on when growing faba beans in North Central Victoria?

For growers in the North Central region of Victoria some of the key factors to consider before growing faba bean are:

1. Potential profitability – grain prices for faba bean have a long-term average of $450/t, but prices can be volatile depending on international and local markets. In recent years, prices have ranged from less than $400/t to $1000/t. A break-even grain yield is likely to be around 1t/ha. However, faba bean can be multi-purpose. The value of nitrogen (N) to the farming system from a faba bean crop can be substantial, with beans contributing approximately 20kg/ha of N per tonne of biomass. In addition, if sheep are part of the farming system, the sheep can show improved growth rates and profitability on faba bean stubbles compared with cereal stubbles.
2. Soil types/condition – faba bean is one of the most adaptable of the pulse crops to a range of soil types. While faba bean prefers a loam to clay soil type, it will also tolerate a sand, particularly if the nutrition of the sand has been improved. Faba bean performs best when pH is above 5.5 but will tolerate a lower pH far better than all the other pulses except lupin. Similarly, to other pulses, avoiding soil toxicities such as salt, boron and sodicity will help to minimise risks to production. Also, faba bean will struggle in compacted soils, so performance will benefit from a no-till, controlled traffic farming system, with retained cereal stubble.
3. Climate – traditionally faba bean has been the best adapted of the pulses to higher rainfall areas (e.g. > 500mm), with good relative tolerance to short term waterlogging. Conversely, faba bean is generally the first pulse to show drought stress, being poorly adapted to the dry regions (< 350mm rainfall). Faba bean also tends to be more sensitive to high temperatures during flowering compared with the other pulses, but more tolerant to cold and frost conditions.
4. Paddock history/rotation – faba bean is generally intolerant of several herbicide residues, including Group I and Group B, so it is important to have good records and know what has been applied to the paddock in the last three years as a minimum. In addition, faba bean is not particularly competitive with weeds, so planting in a paddock with a low weed burden is preferable. Maintaining adequate nutrition is essential. In particular, application of phosphorus is critical to ensure good inoculation and nitrogen fixation.

More detailed considerations can be found in the GRDC Faba Bean Southern Region GrowNotesTM

Key question 2 - How can profit be maximised while risk minimised when growing faba bean (what have we learnt from research and development)?

Some of the key factors for consideration include:

1. New varieties – faba bean now has several well adapted varieties available for growers (Table 1). Choose the best option for your situation.
2. Stubble – retaining stubble will help to maximise grain yield. Twenty per cent gains have been observed in field trials where stubble was retained compared to conventional cultivation with stubble removed.
3. Sowing time – sowing early (late April/early May) maximises biomass production and grain yield. Delaying sowing by one month can reduce grain yield by more than 20%.
4. Row spacing – due to their indeterminate growth, faba bean utilises the available row spacing and can achieve similar yields when planted from 20cm to 60cm row spacing. One benefit from a wider row spacing it the risk of disease can be reduced. Faba bean is well suited to an inter-row sowing system with retained stubble.
5. Sowing rate – research has generally shown that a sowing rate targeting a plant density of 15-25 plants/m² is optimum; a reduced sowing rate with wider rows when sown early and an increased rate when sown late on narrower rows. Disease risks are reduced with lower sowing rates.
6. Inoculation – faba bean is very responsive to inoculation. Grain yield increases of greater than 50% have been recorded following effective inoculation.
7. Disease – considerations for the management of fungal diseases is likely to be needed every season. The specific strategy is dependent on the variety sown and needs to be planned pre-sowing to ensure required fungicides are available at the required time of application. Disease prevention is vital in any management strategy as fungicides are only effective on the parts of the plants that are present during spraying. Subsequent growth is unprotected and susceptible to infection, so an early spray (for example, tebuconazole), often applied with the grass herbicide is critical to success. Strategic sprays (for example, carbendazim) prior to canopy closure and/or rain fronts will help prevent chocolate spot, the most critical disease. Ensure thorough coverage of all foliage to achieve maximum protection.
8. Crop topping – faba bean is well suited to the practice of crop topping, to help control late maturing weeds, especially ryegrass, as faba bean can mature earlier than these weeds.

Key question 3 - What are the characteristics of the released herbicide tolerance bean variety PBA BendocAand what can we expect in the way of further releases going forward?

PBA Bendoc was the first faba bean variety released with high tolerance to imidazolinone (Group B) herbicides when applied post emergent. It also has improved tolerance to sulfonylurea residues that can persist in the soil from application in previous crop rotations. PBA Bendoc has similar yield to other major faba bean varieties grown in southern Australia and is moderately resistant to ascochyta blight.

In the future we will continue to see a range of varieties released with similar herbicide tolerance to PBA Bendoc, but with improvements in disease resistance and adaptability to a range of environments. From a herbicide tolerance perspective, future varieties with tolerance to the Group C and Group I herbicides will provide further weed management options.

There have also been a number of recently released varieties with improved disease resistance. PBA Amberley, with its longer season and improved disease resistance to the common diseases affecting faba bean (Table 1) offers growers in the high rainfall zone the potential to reduce risks of increased foliar disease, and therefore, lower costs of production. In the lower rainfall zones, PBA Marne offers yield advantages compared with older varieties, with its characteristics of earlier flowering and higher grain yield in shorter seasons. From a Victorian perspective, the breeding line AF12025, has demonstrated significant grain yield advantages (20% greater than PBA Samira), which is related to its earlier flowering and improved adaptability characteristics in Mallee environments compared with all currently grown varieties.

Table 1. Faba bean agronomy and disease guide.

S=susceptible, MS=moderately susceptible, MR=moderately resistant, R=resistance.

Key question 4 - In relation to the current season, which diseases are the most threatening, and therefore, what the growers should be looking out for in faba bean?

The critical diseases for faba bean production are generally cercospora, ascochyta blight and chocolate spot. Early seasonal conditions in 2020 were conducive for early infection of both cercospora and ascochtya, with both diseases observed at low/moderate levels in trials and growers’ paddocks. In trials the early application of tebuconazole, provided good suppression of these diseases. Due to the drying conditions occurring in late autumn to early/mid-winter, disease infection did not progress, however the recent rain in early August has the potential to change that. Given good early growth and yield potential, it is essential that fungicides be applied pre canopy closure to ensure suppression of chocolate spot. Current varieties are of much lower risk than varieties from 10 years ago, but it is still essential to prevent the initial infection and keep the lower canopy clean of disease. As a minimum, it is likely that another fungicide application during pod fill will be required to prevent seed infection from chocolate spot.

Acknowledgements

The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC and the authors would like to thank them for their continued support.

Useful resources

GRDC Faba Bean Southern Region GrowNotesTM

Faba bean Online Farm Trials

Agriculture Victoria Pulse Disease guide

References

ABARE, 2020

Contact details

Dr Jason Brand,
Agriculture Victoria, 110 Natimuk Road, Horsham, 3400
0409357076
jason.brand@agriculture.vic.gov.au
@jasonbrand