A group of 25 farmers and supply chain partners who attended the Sustainable Futures event at Albanwise Farms near Beverley were told by soil scientist Neil Fuller to love their earthworms. Neil firmly believes that earthworms are the unsung heroes of the soil; they have a huge influence on the efficient functioning of soil systems and the yield of crops grown within it.
The feeding activity of earthworms, transport organic material directly into the soil, after breaking the material down within their gut. The digestion creates worm casts which helps release these key elements and processed vegetation back into the soil, creating humus. These worm casts are rich in nutrients such as Nitrogen, Potassium, Phosphorus and Magnesium, and are more readily available for a crop to absorb.
Earthworms also have a positive impact on soil structure; their burrows create channels in the soil for drainage, which improves soil aeration, and mixes organic matter into the soil.The worm cast also contains binding agents which helps to develop soil structure by effectively pulling the micro aggregates together.
Worms however do not respond well to ploughing. Being buried deep underground, cut into pieces or eaten by birds severely effects the overall population and reduces the benefit they bring to the soil. Researchers have found that 3 to 4 years of no till cultivation can double earthworm populations compared to ploughed soils.
Increasing the amount of plant residue on the surface by using farm yard manure, chopped straw or growing cover crops will also help to increase worm populations. Matthew Beech, the Albanwise Arable Manager explained that the cover crop we saw had been established following wheat. The wheat straw had been chopped resulting in high levels of worm activity as was evident from the number of casts and the up-right straw stalks that were being pulled into the ground by the worms. On closer investigation, Neil Fuller predicted that there were at least 25 worms per square metre present, which would be creating 60-80Kg of free Nitrogen being available for the next crop.
Matthew said he decided to grow the large scale field trial, after discussing the subject with other farmers and seeing cover crops at previous Sustainable Futures events. Matthew is using this cover crop to improve soil health, structure and increase organic matter content for next year’s crop of vining peas for Birdseye.
The mix he chose contains Mino Tillage Radish, Winter Rye, and Phacelia. Each of these plants brings something different. The radish pushes down large tap roots improving drainage and affording a passage for worms. It also acts as a biocide as the roots exude chemicals that reduce the breeding of soil born pests such as nematodes.
The winter rye which originates from Russia is frost hardy and continues to grow at low temperatures. The crop had produced an impressive root structure, with lots of fibrous growth, helping to condition the soil. It had also generated bio-mass which captures nutrients left by the previous crop along with sequestered carbon. These nutrients get ‘locked in’ to the system and then released to the next crop.The Phacelia within the mix produces high levels of root and organic matter. And also when it flowers it attracts bees and other insects.
Neil suggested that the cover crop actually improves soil health over the winter, when a bare ploughed field actually degrades. The cost to establish the cover crop was approximately £180 per Ha) which our soil scientist Neil Fuller believes will be a good investment. The cost can be reduced by using cheaper seed such as farm saved oats, or mustard. It would also be possible to harvest cover crop seed to grow the following year.
Don’t forget the earthworms working away in your soil, do it for free, making your soil better. If you make life easier for them they will work even harder on your behalf.
A big thank you to Matthew for his time and showing us around the Albanwise farms.