Project Lamport, now in its seventh year, is embracing digital for 2020. The team, including Head of Soils, Chris Martin; Farming Systems Research & Development Advisor, Niall Atkinson; Director of Wright resolutions Ltd, Phillip Wright; and Independent (PhD) Researcher, David Purdy, will be sharing regular updates from the site in Northamptonshire.
For the fifth blog update, wider members of the Agrovista soil heath team interview our Lamport experts to ask the questions that you’re likely to have.
Is the choice of cover crop important?
Head of Soils, Chris Martin
“Blackgrass control certainly influences the species of cover crop we should use prior to a spring crop. It’s important to select a slow growing species that allows blackgrass to grow amongst it so it’s trapped. Then, when the cover crop, ie black oats and phacelia, gets growing later in the season, it develops a lot of bulk below ground. This dries out the soil allowing us to direct drill efficiently in the spring
If we wanted more diversity or a thicker cover crop, we wouldn’t achieve the same success with blackgrass control. So yes, blackgrass control really is influenced by selecting the correct cover crop.”
Are all black oat varieties the same?
Chris Martin
“Black oats are fundamental to the success of Project Lamport but they do vary significantly in vigour and heading date. We should be looking for a variety that doesn’t set seed and become a weed itself. If chosen correctly, the main benefit is root mass and where we have roots we have improved soil biology. Late heading varieties will also have the advantage of a lower C:N ratio – reducing any potential adverse effect on cash crop, if for instance destruction timing is delayed.”
What are the best ways to establish a cover crop?
Farming Systems Research & Development Advisor, Niall Atkinson
“What we’ve used with great success is the Vaderstad CrossCutter to premix residues and create a fine shallow tilth. Cover crop seed could then either be applied off the back of the Crosscutter, or as a separate operation. By working with this machine at a shallow 1-2” depth, we are allowing blackgrass to easily grow among the cover crop.
At Lamport we have followed the Crosscutter with both a combi drill and a cultivator drill for a direct comparison. Having successfully direct sown our covers, good residue management is essential with this technique.
We’re also regularly asked about soil loosening and my default is to move the soil as little as possible below ground. This is because we know that the more we move the soil, the more we mix grass seed through the soil profile. My judgement for this is the previous crop – if we’ve harvested a good yield then there is likely very little wrong with that field. As long as we manage our harvest traffic it should be structurally sound requiring only shallow cultivations.
If we want to use metal to compliment the roots, we’ve found that using a low disturbance soil loosener similar to what is used to establish oilseed rape is best. But, our default at Lamport is no metal in order to benefit soil health.
We are also experimenting with broadcasting covers direct into the crop prior to harvest. This is the ultimate technique - timely low-cost establishment with nil soil movement.
Do you have thoughts on successfully destroying a cover crop?
Chris Martin
“Whilst the cover crop might successfully be controlled by grazing or mechanical means; for blackgrass we have to consider glyphosate and timing is key. When using a cover crop for blackgrass control, we need to destroy it early around January time. When we’ve done this at Lamport we’ve achieved 0.5t/ha increase in the following crop yield, compared to those after a later cover crop destruction. This is because it allows the soil to dry out as well as achieve greater success with the direct drill. It also encourages biomass to decompose and nutrients to mineralise and become available for the spring crop. Later destructions can have the opposite effect by immobilising nutrients. So for blackgrass control, we recommend earlier destruction.”
Any tips for drilling the spring crop?
Niall Atkinson
“One thing that we learned through our mistakes is how important the direction of drilling is. Going at 90 degrees to the direction of the cover crop creates more soil movement. So a key learning is that you must drill the cover crop in the same direction to what you intend to drill your spring crop.
Choosing row width is also important. Wider row spacing isn’t necessarily the best for the systems we have at Lamport. Most of our work is with drills working at 160-170mm spacing and we’ve learnt this because where we’ve had wider wheelings, we’ve found blackgrass. That tells us that we need good crop competition there. If you were drilling into late destroyed bulky covers, you might struggle to get flow through the drill with a very narrow spacing. So 160-170mm seems to suit us best.
That leads onto seed rates which are critical. Here at Lamport our best establishment rate for spring wheat has been around 65-70%. That means if we used 250-300 seeds per m2 we’d likely have poor crop competition. So we’re up to 500 seeds per m2 for spring wheat and 450 seeds per m2 for spring barley.”
Do you think this system could work for other spring crops?
Niall Atkinson
“Judging by this crop of spring oats I would say yes it does work. Here we’ve needed no grass weed pre-ems so I think it’s safe to say that Project Lamport has taught us how to successfully grow spring crops on heavy land.
After seven years with all of the conditions possible thrown at us, we always get the job done.”