Intercropping results: are two crops better than one?

We are definitely doing this again next year, we’d be stupid not to. In fact, we’ve already ordered our seed.”

James Hares farms on heavy Wiltshire clay with his father Adrian, who is coordinator of the Wilts Soil and Root Innovators. This year, James was one of four farmers who took part in a field lab on Intercropping. The group received funds from the four-year Horizon2020 project, Diversify and are applying to the Innovative Farmers research fund for next year.



Weed suppression at Roundhill Farm, Wiltshire

James trialled winter wheat grown with beans to provide fodder for his beef herd. He drilled in October at 175kg/ha, his usual rate for the beans, adding 125kg/ha - 50% of his usual rate of wheat. As his trial field had an extremely high wild oat burden, and as an organic farmer, James’ main motivation for trying intercropping was weed suppression.

“The beans were our main crop so any wheat we got was a bonus. We actually saw slightly lower bean yields where we intercropped but this was more than made up for by the wheat. Crucially, we saw 62% less weed biomass in the intercropped plots. With far fewer weeds, we should have a much cleaner field next year.

“This is our first foray into intercropping and we are convinced it was worthwhile. Having the extra biomass in the form of a wheat crop - rather than weeds - is hugely beneficial. Next year, we’ll probably drop the wheat rate to around a third to try and boost our bean yield while still suppressing the weeds.”

Disappointing OSR but lots of bean potential for Andy Howard


James didn’t have any problems drying the grain and is storing the wheat and beans together, so avoiding the need for separating. Rather than providing fodder, Andy Howard, who is based at Bockhanger Farm in Kent, is looking for two marketable crops and needs to separate his harvest using a machine he’s built himself.

This year, Andy intercropped his beans with spring oilseed rape, but the plots were still waterlogged in March meaning he drilled a month late. This late start, combined with slugs, cold/ wet soils and then pollen beetle later in the year, resulted in a very disappointing oilseed rape crop.

“I was growing the oilseed rape as a companion crop. This year pollen beetle was a major problem in the OSR and we spent money trying to control them, it didn’t work. Next year, I may use SOSR again – maybe with a higher value pea – but I won’t spend money on inputs for the companion crop, it’s too risky.

“The other interesting thing we noticed was that in July, the intercropped beans had at least 50% more flowers. They were podding right down the stem whereas the monocrop only started halfway up. Unfortunately, we then had the long, hot spell meaning that the flower potential didn’t translate to the final yield. Whether this difference was down to seed rates or something else we can’t be sure but I’m interested to see whether it’s repeated next year.”

Lodging risk management for Mark Lea

As well as weed suppression and providing a second crop, there are other reasons for intercropping. Mark Lea grows pulses for Hodmedod’s. This year he grew carlin peas intercropped with triticale to reduce lodging and provide scaffolding for the peas. Where the triticale rate was highest at 30% (75kg/ha), there was a small reduction in pea yield but they stood better and were significantly easier to harvest.  There was also a small reduction in weed level which is a very useful bonus.

Next year, Mark says he would plant at the higher rate, even if it meant taking a yield penalty on his peas. This year’s low rainfall meant that there were particularly low levels of lodging on the farm. In a wetter year, the rain could result in far more damage to the crops if they don’t have the scaffolding provided by the triticale. There’s also a higher risk of damaging the combine.

As well as the trials on James, Andy and Mark’s farms, there were trial plots at the University of Reading, and the whole field lab was part of a Europe-wide project on intercropping called Diversify. The four trials were funded under grant number 727284. If you’re interested in taking part in next year’s trial get in touch with group coordinator, Charlotte Bickler from the Organic Research Centre.

See the results and find out more about this field lab >

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