Saturday, August 24, 2019

Soil studies ramped up at flagship arable trial site

August 8, 2019 by  
Filed under News & Business

Agrovista has extended its Project Lamport flagship trials in Northamptonshire with an increasing focus on soil health to help growers overcome blackgrass and grow more profitable cereal crops.

Project Lamport was set up in 2013 to investigate cultural solutions to help growers tackle severe blackgrass infestations while growing profitable crops.

The project has been a big success, showing that spring wheat can be reliably drilled on heavy land following a black-oat-based cover crop to achieve those goals, says Agrovista technical manager Chris Martin.

“However, the work is still throwing up many technical questions. Soil health is now a key driver at Project Lamport as well-structured soils are the basis for efficient farming and effective grassweed control.

“We are observing substantial physical and biological improvements in the soil and we are now starting to measure these to put some real science behind our recommendations.” 

Independent cultivations expert Philip Wright is examining the benefits of assisting natural soil structuring using various combinations of roots and iron, reducing the need for heavy, expensive cultivations.

“On the heavy clay at Lamport we currently need both roots and tillage to get crops off to the best start. But how much of each do we need?”

In the damp autumn and wet winter of 2017/18, a shallow, low-disturbance post-harvest cultivation to 12.5cm combined with a black oat-based cover crop established soon afterwards resulted in much better spring wheat establishment compared with other treatments.

Drier conditions

This season’s trials were established in drier conditions. Some plots were shallow-cultivated post-harvest to a few centimetres, others loosened to 12.5cm or 25cm with low disturbance legs, with and without discs.

Half of each plot was then sown with a black-oat/phacelia cover crop on 30 August, the other half left bare over winter. All plots were direct drilled with spring wheat on 21 March.

Loosening to 12.5cm with cover crop again appears to be the best option in terms of soil structure, crop appearance and blackgrass control, says Mr Wright. “The crop roots have improved the soil profile and cultivation has done enough to get roots well below leg depth. Looking at the other half without the cover crop, there is a distinct lack of tilth and porosity.

“The plot that was treated the same but cultivated to 25cm looks no better, but cost twice as much in diesel alone. Going deeper has not achieved anything.”

Yield will be judged and blackgrass levels assessed. “Eventually we will be able to advise on the best ways to move towards a low or no-till operation on heavy soils so that roots are doing most of the work for us.”

Measuring the benefits

A three-year study at Project Lamport to collate and measure the benefits of good soil management is being undertaken by David Purdy, PhD candidate and John Deere’s East Anglia territory manager.

Mr Purdy is examining the impact of roots across a range of cover crop species, singly and in mixtures, with and without iron. Assessments include compaction, soil bulk density, visual assessment of soil structure, worm counts, mycorrhizal colonisations and organic matter levels.

Early findings are showing a gradual increase in earthworm numbers where tillage is reduced, particularly under cover crops.

Water infiltration rates increased where a black-oat-based cover crop was used. Soil aggregation also improved, potentially providing a more open structure.

“Judging by the initial findings we might expect to see some big differences over the next two to three years,” says Mr Purdy. 

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