GroundCover™ Issue: 137 November - December 2018 | Author:Jo Fulwood
New disease-resistant varieties of faba beans are being trialled in forest gravel soils with strong early results suggesting a bright future in WA for the alternative legume
WA DPIRD’s Dr Raj Malik, who is managing the GRDC-invested trials, says accurate seed inoculation, plus good establishment, could be the key to achieving profitable yields in this region.
“We are investigating the crop response to nutrients and rhizobium to ascertain whether there is some specific strategy that will allow the faba beans to be profitable in this part of the state,” Dr Malik says.
“We know faba beans are grown in the more southern regions of WA, but we are hoping to try and replicate this success in the Great Southern region.”
Several years before these WA DPIRD trials began, Ben Webb had already seen the potential of faba beans and had run his own on-farm experiments investigating seeding rates, fertiliser rates and the new varieties.
He says after 10 years of heavy liming, his soils are now sitting at about 5.5 pH, which is the starting point at which faba beans can become part of his system.
Results from these early trials surprised him, with some very early treatments yielding up to one tonne per hectare – a good first result in what Ben says are non-wetting, gravel soils.
But he believes the potential is there for yields of up to 2.5t/ha in his region if he can manage the agronomy accurately.
Farmanco agronomic consultant Chris Robinson, who has been working with Ben on these experiments, says faba beans offer the best available nitrogen fixation out of all the available legumes, but the real reason for looking closely at faba beans in the system is their ability to reduce nematode numbers.
As little as two decades ago, faba beans in Western Australian grain-growing regions were commonly and un-affectionately called “failure beans”, with diseases such as ascochyta blight and chocolate spot all but wiping them out.
Traditionally suited to alkaline soil types, faba beans have since struggled to gain much attention in WA’s acidic soils.
But newly released varieties, with stronger disease packages and more acid-tolerant rhizobia, could now make faba beans a viable and profitable option, particularly as growers search for solutions to the devastating effects of root lesion nematode and Rhizoctonia disease.
GRDC-invested WA Department of Primary Industries and Regional Development (DPIRD) trials of two new varieties of faba beans on the property of Ben and Emily Webb at Kojonup, WA, are attempting to determine if this legume might come out from the shadow of its “failure bean” label and be a profitable option for growers in this Great Southern region.
In 2017, the WA DPIRD trials compared the AF11023 and PBA Samira varieties to determine which was more suited to these soils (Table 1); however, there was no significant yield difference apparent between the two.
This season, four treatments in the trials are again comparing PBA Samira and AF11023, but the trials are also looking at varying rates and timing of nitrogen and phosphorus, plus the use of several new acid-tolerant rhizobia to fix the nitrogen at the root zone.
Results from these trials will give growers in these acidic soil types some guidance as to how to accurately manage the agronomy of a faba bean crop for the most profitable outcome.
Growers: Ben and Emily Webb Location: Kojonup, Western Australia Farm name: ‘Mararrup’ Size: 2150 hectares (arable) Enterprise: mixed crop and livestock (4500 ewes) Grains: wheat, lupins, barley, oats (for hay) Average annual rainfall: 500 to 550 millimetres pH: 5.0 to 5.5 Soil types: duplex forest gravels
“We are seeing yield losses of up to 1.5t/ha in some of our cereal crops in this area, and up to 300 kilograms per hectare in the canola, purely because of nematodes in the soil,” Chris says.
“The ability of faba beans to reduce nematode numbers has been widely documented, and if we can work out how to grow them in this soil type, then they could have a huge impact on our ability to grow high-yielding cereals.”
Ben says his experiments are simply about trial and error, working out how to manage the beans using his current seeding and spraying equipment.
In the long term, he knows if he wants to keep beans in the system he may need to consider specialised equipment more suited to sowing beans.
“In the first year we mixed faba beans and vetch together in the paddock, but the vetch grew too high and fell over and took the faba beans with them, so that combination wasn’t a success,” he says.
The following year the Webbs put in one treatment using double the seeding rate (about 180kg/ha) and double fertiliser rates (at about 200kg/ha), with a blended product of nitrogen, phosphorus, sulfur, potash and manganese with lime incorporated.
Ben says this new treatment effectively doubled the yields up to 2t/ha.
“From these trials, we think the most significant and economical agronomic tactic is to keep seeding rates up around 180kg/ha,” Ben says.
“Our results show that this is by far the best and most profitable way to achieve those higher yields.”
This year, Ben has planted 25ha of the variety Farah, as an alternative to canola and lupins, and has increased sowing rates to try to target 40 plants per square metre, which was calculated from his 1000 seed count weight measurement and the effect of water-repellent soils on germination percentage.
Chris says the new chocolate spot-resistant variety and the new acid-tolerant rhizobium will be of major benefit to Ben’s business.
“Hopefully new radish control options will arise in the future because this will be the next limitation to growing faba beans,” he says.
Ben has been searching for an alternative legume since he noticed the impact of disease, such as sclerotinia, in his canola yields and the effects of Rhizoctonia in the lupins.
The impact of root lesion nematode has also been a significant concern.
“While canola has been our most profitable crop over the past decade or so, and lupins are also very dominant in our system, we need to find another profitable legume to introduce into our rotation to protect the soils from disease and weeds, and to fix nitrogen for our cereals.”
While Ben’s faba bean crop will be used as stockfeed for his 4500-ewe flock, global demand for the beans for human consumption continues to be strong.
According to Pulse Australia, faba beans are currently one of the most profitable of all legumes.
Australian faba beans are predominantly exported to Egypt, therefore escaping the current Indian tariffs on pulses.
Pulse Australia chief executive officer Nick Goddard says there is also a strong market for faba beans as stockfeed and pet food, given its high protein content when compared with other pulses.
He says new season faba bean prices are at the higher end of their historical price decile.
“With a shortage of stockfeed available this season, particularly on the east coast, faba bean prices have generally stayed higher than most other legumes,” Mr Goddard says.
While faba beans are more commonly grown in eastern Australia, more than 2000t were exported from Fremantle port in 2017.
Almost all these beans came from one WA grower who has been growing the legume since 2003, with significant success.
Mark Wandel, who farms at Scaddan in WA’s south-east coastal region, grew 1400ha of faba beans in 2017, achieving yields of more than 3t/ha. Mark’s annual rainfall is about
450 millimetres and his faba beans are planted into heavy alkaline mallee soils.
This year he has 1050ha planted to faba beans.
Mark is so invested in the crop as part of his system, he has purchased an 18-metre seeder bar and now also has a shielded sprayer.
He credits some of the success of the crop on his farm to the 750mm-wide row spacings, which he says allows the crop to set flowers and seed earlier in the season because of the increased access to sunlight and the greater airflow through the plants. These wider row spacings also allow for easier disease and pest control.
Mark says faba beans cost him up to $60 to $70/ha more to grow than field peas, but believes this outlay is worth it for both the long-term nitrogen investment for subsequent cereal and canola crops and the higher export prices he is achieving.
But it was not that long ago that he remembers seeing entire faba bean crops wiped out by disease.
“We first planted beans in the late 1980s, and I can remember harvesting 50ha of four-foot-tall faba bean crops and not even getting a box full of grain,” Mark says.
“So we went out of beans in the early 1990s and didn’t attempt them again until 2003, when we had access to varieties that were much more disease tolerant.”
Mark says faba beans are here to stay in his rotation with farmgate prices ensuring the crop is not just returning nitrogen to the soil, but also returning a profit in the year it is grown.
In Kojonup, Ben is hoping to include more of the beans in his rotation in coming seasons once the WA DPIRD trials can shed more light on the best agronomy for the legume in his challenging soil type.
TABLE 1: WA DPIRD 2017 trials on Ben Webb’s property, Kojonup, WA. SOURCE: Dr Raj Malik, WA DPIRD.