I have a NBF & I've discovered Charles Darwin had a fascination with earthworms. What an extraordinary man & to my surprise what a relatively easy read. I found his words drew me into what is really a story of today about climate change, importance of soils to humanity, importance of pasture based farming. A great read & its online.....free! Charles Darwin was absolutely besotted & totally absorbed intellectually by earthworms. 
http://darwin-online.org.uk/content/frameset?itemID=F1357&viewtype=side&pageseq=1“It may be doubted whether there are many other animals which have played so important a part in the history of the world as these lowly organised creatures “ & “Without the work of this humble creature, who knows nothing of the benefits he confers upon mankind, agriculture, as we know it, would be very difficult, if not wholly impossible”(Charles Darwin 1881)
Not only did Charles Darwin intensely study earthworms at Maer Hall in Staffordshire (home of his Uncle Josiah Wedgewood) & at his home in Down House in Downe Kent but his sons Francis & Horace were roped into counting & observing worms (for at least 15 years) ....imagine that today!http://www.maerestateholidaycottages.co.uk/cms.php?holiday=History http://www.english-heritage.org.uk/daysout/properties/home-of-charles-darwin-down-house/garden/ I urge you to read some of this amazing (but easy to read) book….I suggest you try pages 129-137 for starters. http://darwin-online.org.uk/content/frameset?itemID=F1357&viewtype=side&pageseq=1
Darwin outlines his trial where he spreads quick lime & then coal cinders onto the pasture at Maer Hall. He then observes for an amazing 21 years how earthworms cover up & eventually bury the two layers, which are to become his measuring markers. “The average annual increase of thickness for the whole period is 1·9 of an inch” (4.8cm/year). He was in effect growing top soil! Year on year the earthworms are growing the topsoil....in the book there is a diagram illustrating the new depth of topsoil after 21 yrs. This is incredible but so important to every pasture based dairy farmer....this is the engine room of your business.
Darwin estimated that a healthy English acre ought to have about 2,500,000 worms, turning out 18 tons of casts a year.There should as a rule of thumb be at least 25 earthworms per square spade full of top soil under pasture In a pasture based dairyfarm is it accepted that the quantity of “livestock” under ground in the soil needs to be the same as the kgs livestock above the ground.So if you want to increase the number of cows the implication is that you must increase the "soil livestock" too, otherwise it wont be in balance eg you wont produce the extra pasture either as a result of not looking after the soil. This is of massive importance. 
Fiona Hillman (Wyegraze DG) in her very good Nuffield study 2007 on earthworms emphasizes the need to provide this "soil livestock" with food, water & air in a healthy soil environment. http://www.nuffieldinternational.org/reports/report.php?y=2007 Fiona writes in her Nuffield report that :- “It has been estimated that with a healthy population of endogeic and anecic earthworms, 1100 miles of burrows could exist per acre, if undisturbed”
Fiona Hillman (Wyegraze DG) in her very good Nuffield study 2007 on earthworms emphasizes the need to provide this "soil livestock" with food, water & air in a healthy soil environment. http://www.nuffieldinternational.org/reports/report.php?y=2007 Fiona writes in her Nuffield report that :- “It has been estimated that with a healthy population of endogeic and anecic earthworms, 1100 miles of burrows could exist per acre, if undisturbed” Hence her Darwin quote that :-“The plough is one of the most ancient and most valuable of man’s inventions; but long before he existed the land was ploughed, and still continues to be ploughed, by earthworms”.We've got to stop ploughing & look to alternative technology!
Pasture based dairyfarmers are really “carbon” farmers. The pastures capture the sun’s energy through photosynthesis. The target annual pasture production is in excess of 10TDM per hectare in the UK. Dairy cows efficiently harvest the pasture to produce high quality milk, but that’s only half the story. Approximately 30-40% of the plant energy (carbohydrates) is fed through to the massive root system (a huge store for carbon). Much of this root material eventually ends up feeding a diverse soil biology including our friends the earthworms. The term “Carbon Grazing” is a concept of a very observant farmer in Queensland Alan Lauder. www.carbongrazing.com.au. Alan in his book “Carbon Grazing” says that “Rural producers have to manage their pastures so that all life in the soil is fed”. This is a really interesting comment but directly associated with carbon & soil organic matter. Fundamentally we need to shift our focus from cows & pastures to our soil & once we get there we need to zoom in on carbon. We cant forget cows or pastures but our profits & long term sustainability will depend on how successfully we as pasture based dairy farmers manage carbon & the carbon cycle on our farms. In his conclusion Alan writes that “Changes in the way we farm must be linked to changes in the way we think”
Current UK Pasture Measurements Pasture growth still very variable dependant on rain. Becoming quite serious in souther England, Germany & Brittany France
Keep grazing rotations long....a NZ visitor this week said hang in there as NZ had a very similar spring early summer then it turned & they had a brilliant autumn.
Pasture based dairyfarmers are really “carbon” farmers. The pastures capture the sun’s energy through photosynthesis. The target annual pasture production is in excess of 10TDM per hectare in the UK. Dairy cows efficiently harvest the pasture to produce high quality milk, but that’s only half the story. Approximately 30-40% of the plant energy (carbohydrates) is fed through to the massive root system (a huge store for carbon). Much of this root material eventually ends up feeding a diverse soil biology including our friends the earthworms. The term “Carbon Grazing” is a concept of a very observant farmer in Queensland Alan Lauder. www.carbongrazing.com.au. Alan in his book “Carbon Grazing” says that “Rural producers have to manage their pastures so that all life in the soil is fed”. This is a really interesting comment but directly associated with carbon & soil organic matter. Fundamentally we need to shift our focus from cows & pastures to our soil & once we get there we need to zoom in on carbon. We cant forget cows or pastures but our profits & long term sustainability will depend on how successfully we as pasture based dairy farmers manage carbon & the carbon cycle on our farms. In his conclusion Alan writes that “Changes in the way we farm must be linked to changes in the way we think”
Current UK Pasture Measurements Pasture growth still very variable dependant on rain. Becoming quite serious in souther England, Germany & Brittany France
Keep grazing rotations long....a NZ visitor this week said hang in there as NZ had a very similar spring early summer then it turned & they had a brilliant autumn.
TheAverage Pasture Cover (kgsDM/ha) & Pasture Growth (kgsDM/ha/day)
Northern Ireland, AFC 1987, Growth 65kgs, lots of rain & hail but cold
South Ayrshire, Scotland, 2269, gr 39 & demand 77, soil temp 14.3, expecting better growth
Cheshire organic, 2000, gr 20, demand30,feeding 3.6kg conc, mowing silage fields
Oxford, 2250, gr42, demand 38, rotation 32 days still very dry & grass heading
Gloucestershire, 2063, gr48, 12mm rain over week milk holding well
Somerset Organic, 1900, gr 25 currently raining heavily so growth should increase
Dorset, 2223, gr27, rotation 50 days pasture quality poor
Dorset, 2223, gr27, rotation 50 days pasture quality poor
Sussex organic, 1486, gr16. good rain this week....excitement!
Cornwall, 1930, gr43, demand 60, may go OAD early if no rain
South Kilkenny Ireland, 1969, gr35, demand 46
Northern Germany organic, 1970, gr45, demand 47, cows on OAD
Brittany, Finistere, France, AFC 1700, virtually NO growth, Looks like an Australian farm....what do you mean Erwan?
Summer of 2005 a distant memory in Brittany...did it really look like this????
Under good dairy pastures & sound grazing management is usually a healthy soil environment. Permanent pastures encourage build ups of Soil Organic Matter & healthy soil life. However all that happens on UK low input dairy farms does not favour a healthy soil. E.g. excessive use of Nitrogen, poor drainage, poor use of manures or cultivation/ploughing.
During & post WW2, Winston Churchill ordered as much of the UK that could be ploughed should be so that arable crops could be grown to feed the nation. The response & the efforts of farmers fed the nation, the right call at the time. Ploughing & cultivation however increases the potential loss of topsoil & destroys the soil structure & certainly speeds up the loss of soil organic matter. These are serious issues to be addressed by the arable industries but pasture farmers need to take heed too. 
Shane had a very clear long term environmental plan to improve the sustainability of their farm business based on having a soil capability map. 
We need to move away from thinking that ryegrass/clover is our only option especially on dry soils. It may not be our best option to increase soil organic matter (SOM) either so we need to start looking outside the box.
Organic matter is critical for soil health and for soil productivity. It:
Soil organic matter is:
