Managing cover crops for soil health & yield

The Cover Crop Management group are exploring alternative ways to destroy cover crops in a field lab that’s been running since 2016. The arable farmers want to find new ways to terminate cover crops while reducing inputs and minimising soil disturbance. We caught up with them about the early results and discussed what’s next.

Trialist farmers James Alexander, David White and Phillip (Pip) Partridge each planted their cover crops in Summer last year; they monitored establishment and trialled their chosen method of destruction. The techniques they trialled ranged from flailing, crimper rolling, and even trying to scorch the cover crops away by spraying them with liquid fertiliser. 

Like everyone in the UK this winter, the group endured the ‘Beast from the East’. The bout of unseasonably cold weather that gripped households – and farms – across the nation. This affected some of the trialist’s crops and resulted in some mustard and pea crops being killed off which saved any need for interevention. James Alexander recalled how his farm hit -9 degrees leaving patchy crops with volunteer weeds.

In a recent update meeting, the group reflected on how timing is key when sowing cover crop mixes to ensure there is still enough moisture in the soil for the plants to get established and compete with weeds.

“Looking back, I should have put a graminicide on it” said James, "this would’ve taken out the volunteer weeds, just leaving broad leaves, which are easily managed in the following crop without using glyphosate."

David White sowed his crops earlier and destroyed them before Christmas, meaning they were gone by the time the storm hit in February. Being unaffected by the weather meant he could trial an impressive number of methods of destruction including rolling, flailing and crimping – he rolled and crimped two segments twice to see the effects.  

Having sown his mix earlier too, Pip Partridge’s crops fared well and most of the species made it through the freezing temperatures. He tested the effectiveness of destroying crops by spraying them with high concentrations of fertiliser – that he distributed via a fan jet. Pip has seen this work before and was intrigued to see if this could be a reliable method of destruction.

What did you learn?

Unfortunately, spraying the crops with fertiliser had no negative effect whatsoever, in fact, Pip commented that “the radish really enjoyed the fertiliser”.  He suspected that the crops weren’t sensitive enough to be killed by the application, but it could work under the right conditions.

James’ trial didn’t see the effects he had hoped for either as the late drilling meant that half of his trial had to be abandoned. Despite this, he still feels that he learned something valuable from the field lab.

“I learned more this year failing,” said James, “the management to start with is just as important as the destruction.”

Next year he will do things differently and has decided not to plant cereal cover crops in land where cereal volunteer weeds are present. This way he will avoid killing his crops when using a graminicide to control weeds.

David’s trial was more successful; he observed that in one test plot the crimper was more effective than the flailer, and crimping twice ensured any green shoots were killed off completely. Adding more weight to the crimper might mean that in future, the same effect can be achieved with a single pass. James Alexander, who built the crimper, will be seeing how he can adapt the machine ready for next season.

David was happy to see the effects of the early mechanical destruction and concluded that “going forwards [it] will enable us to use less glyphosate. By doing the majority of the destruction early with mechanical means, perhaps a half a full rate would suffice.” 

Other benefits

On top of these findings, the group observed other benefits to participating in the research and continuing to use cover crops. David noted that “my companion work in weight suggested that the beans had fixed 4kgs of nitrogen. The barley where the beans and phacelia were is fantastic." James also noticed that his plough “went easier” on bits of land that had grown cover crops. He said “there are benefits even if you're not following the system fully through.

 

Why is this research important?

All the farmers took something away from this part of the trial, even if it wasn’t what they expected. For them, coming together for Innovative Farmer group meetings is very helpful. “It's nice to get around and look at other people's farms and see what they're doing,” said David. He added that “without Twitter and farming magazines we wouldn't see people doing similar things to us which builds our confidence.” Pip agreed “It's nice to get a group of like-minds like this together. It's a kind of positive peer pressure.

The group are next due to meet in July to discuss harvesting protocols. Watch this space to find out what effect these alternative methods have on yield and find out what the group will do next.

 

Field lab perspectives: Hear from other Innovative Farmers >

Visit the group's page to see their most recent achievements >

 

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