Cracking research at Project Lamport
Soil compaction trials at Project Lamport should deliver some fascinating findings next year, explains independent cultivations expert Philip Wright of Wright Resolutions.
Roots are the ultimate soil conditioning solution, so we shouldn’t pass up the opportunity to use them
Image: Philip Wright of Wright Resolutions
When it comes to soil health, the current season demonstrates clearly why we need to continually assess conditions rather than follow a prescription, however tempting the latter may be. Many soils are showing very significant levels of cracking due to the prolonged dry weather, to depths we’ve not seen since 1976.
This deep cracking is potentially very good news and will be at the forefront of the compaction trials on the heavy clay loams at Lamport.
The primary aim of Project Lamport is to investigate the benefits of various rotational cultural methods to control blackgrass.
Well-structured soils that drain freely and encourage vigorous crop root growth are the cornerstone of any blackgrass control programme, so this season presents a great opportunity to find out which techniques, if any, will optimise the benefits of nature’s own subsoiling operation.
The first thing to consider is cultivations.
In many cases, substantial savings will be possible when it comes to establishing crops this year, and the Project Lamport compaction trials will reflect this.
On well-cracked soils, deep loosening is, generally speaking, unnecessary.
It disrupts nature’s jigsaw, breaking subsoiler legs in the process. A shallow loosening pass is a better option, creating a mix of tilth and small clods. Some clods will fall down the cracks, acting as spacers.
Although they will eventually be crushed as soils moisten and expand, they will help maintain a network of fissures that could last several years.
At Project Lamport, some plots were shallow cultivated to a few cm, while others were loosened to either 15cm or 25cm, both with low disturbance legs and with/without discs. A further plot was left undisturbed and fallow.
Two different cover crops are being tested on the cultivated plots; a combi- drilled black oats/phacelia mix and a combination of black oats sown behind the loosening legs followed by broadcasted phacelia.
We want to see if the latter approach helps black oat roots blast down the cracks and fissures, to hold them open for longer.
Roots are the ultimate soil-conditioning solution, so we shouldn’t pass up the opportunity to use them. Other cultivated plots that were left bare will provide an interesting comparison.
Cover crops also play a vital role in blackgrass control on heavy soils, allowing the weed to germinate and establish before being sprayed off with the cover crop in early winter.
The cover crop also helps “pump out” moisture, especially important when delaying drilling to late autumn or spring.
All three areas will be planted with spring wheat, where establishment, growth and yield will be judged and blackgrass levels assessed.
It will be fascinating to see if we can get away with doing less cultivation or even none to reap the full benefits of nature’s own subsoiling technique.
More fresh thinking at Project Lamport
Project Lamport has clearly demonstrated that profitable crops of spring wheat can be reliably drilled on heavy land in combination with a black oat-based cover crop to reduce the blackgrass burden. However, the trials continue to throw up lots of questions that we need to address to maximise the potential of this and other aspects we are investigating.
New trials work for 2018/19 includes:
Soil compaction trials (roots and steel) – new trials with fully replicated plots
New cover crop combination – black oat and phacelia
BYDV – managing cereal volunteers in autumn cover crops
Autumn cover crop establishment – reduced cultivations
Biologicals – mycorrhizal inoculants
Flea beetle – OSR stubble length comparison