Malcolm, Des and Adrian Kohlhagen have increased faba bean plantings to 25 per cent of their 1800-hectare grain farm near Collingullie, in southern New South Wales.

The move follows their purchase of a disc seeder for sowing and a stripper front for harvest. The ‘strip and disc’ system allows a thick mat of crop residue to build up on paddock surfaces to retain moisture.

Initially, the family grew 50 per cent albus lupins and 50 per cent faba beans, but in the past two years they have eliminated lupins.

Malcolm Kohlhagen and his family have lifted faba bean production to about 25 per cent of their cropped hectares near Collingullie, New South Wales. Photo: Nicole Baxter

Faba beans are now sown in the crop sequence before canola and cereals. Two break crops in succession enable the family to use different herbicides to help drive down grass weeds so cereals can be sown into clean paddocks. An added benefit of this ‘double break’ is that it reduces the level of crown rot inoculum in paddocks.

Waterlogging tolerance

Malcolm says the family’s shift to faba beans was also driven by their ease of sale compared to albus lupins and their superior waterlogging tolerance.

“Seven years ago, when we grew albus lupins, the season was wet, and the lupins on a third of one paddock died,” he says.

A small amount of the family’s lupin seed was contaminated with faba beans, and Malcolm noticed half a dozen faba plants in the corner of the paddock, chest-high, waterlogged and flowering. By contrast, the albus lupins were dead.

“It gave us a first-hand look at the tolerance of faba beans to waterlogging,” he says.

The Kohlhagen family also has a paddock adjacent to the Murrumbidgee River, which flooded late one season. Malcolm says the unflooded area yielded three tonnes per hectare of faba beans, while the flooded section, although yellowed, yielded 1t/ha of grain.

He says harvesting the faba beans that year was challenging because silt from the flooding coated the leaves. “You couldn’t see the harvester. It was one big cloud of dust. But it showed us how well faba beans tolerate ‘wet feet’.”

Sowing adjustments

The Kohlhagen family’s disc seeder is set on 166mm row spacings to provide crop competition against weeds. Photo: Grassroots Agronomy

When the Kohlhagens first planted PBA Samira faba beans, their seeder was set on 330-millimetre rows. They set up the seeder so the faba bean seed would run through every second row. They did this by removing the head cap and plugging up every second outlet.

“We stopped sowing on every second row partially because we see better weed suppression when we plant on narrower rows,” Malcolm says. “We can’t see any difference in our faba bean yields.”

In the first couple of years of growing faba beans, it was a “bit of a battle” moving the seed through a tyned and press wheel seeder.

“On our Simplicity seeder, there was a fan for calibrating the sowing rate, and it took quite a bit of effort.

“One year, we had slightly larger seed, and we really struggled until I found a kit that reverses the feed roller, so instead of the seed going under the roller, it went over the top.”

That simple adjustment eliminated all the grinding by forcing the seed through the roller, he says.

Since buying a disc seeder, the sowing speed for faba beans is about 10 kilometres/hour.

“An advantage of 166mm row spacing is we are not trying to force as much seed down each individual seed distribution tube because the bar is set on narrow rows,” he says. “Seed and fertiliser are placed down the same tube.”

Seed inoculation

Malcolm and his family use a double rate of wet slurry to inoculate faba bean seed.

However, with faba beans now earmarked for planting once every four years, he feels he might be able to “knock that back to a single rate”. Previously, faba beans were sown once every eight years.

They use an old concrete truck agitator to coat the faba bean seed with the wet slurry. “We run the mixer until the inoculant dries on the seed.”

Acid subsurface

Rather than incorporating lime at sowing, the Kohlhagen family uses deep tillage to mix lime through the soil to overcome the yield-robbing effects of subsurface acidity on faba bean yields.

“We usually incorporate 4 to 5t/ha of lime to a depth of 180mm, depending on soil test results,” Malcolm says.

“We incorporate the lime after the canola phase, which means that cereal stubbles have largely broken down before incorporation.”

The Kohlhagen family chose the Lemken Rubin 12-disc harrow to incorporate their lime, mainly because it was half the price of other deep tillage options.

“We like to ensure the soil is relatively moist to prevent the machine from bringing up clods. We then run harrows over the soil after incorporating the lime,” Malcolm says.

At this stage, he says it is unknown how quickly they will need to re-lime.

“We have done some soil testing after using deep tillage to incorporate the lime, and it has done a reasonable job of mixing the lime through the subsurface to the depth of the acid throttle.

“We aim to keep our pH_Ca above 5.8, but much of our country has a pH_Ca of 6.0 to 6.4 in the top 5cm.”

Harvesting and marketing

Malcolm says the concaves in their harvester are changed from narrow to wide wire types when harvesting faba beans.

Although his family has considered windrowing the faba beans, they have not yet done so for fear that the seed will discolour if it sits too long in the windrow.

“We don’t want to lose the colour because we want to be able to sell them for human consumption or FAB1 grade.”

Storage benefits

The family has limited sealed storage, but Malcolm says faba beans store well in unsealed silos and even better in sheds.

“Storing faba beans in sheds is okay because they allow the beans to breathe. If you put them

into an old, unsealed silo, without sufficient airflow, you can end up with a crust at the top where moisture collects. You don’t see that if you store in a shed.”

Going forward, he says he might need to expand his plantings beyond PBA SamiraA to include another variety with a different maturity.

“Another variety would reduce the frost-heat risk and assist our harvest logistics.”

Malcolm Kohlhagen shared his experiences at the GRDC-Brill Ag faba bean focus workshop at Ganmain, NSW, in March.

More information: Malcolm Kohlhagen, m.j.kohlhagen@bigpond.com