Western Daily Press (Saturday)
Soil carbon can prove a valuable resource
Farmers have a role to play in providing stable habitats, says Wiltshire dairy farmer Ro Collingbourn
RECENTLY farmers, or more accurately food producers, feel they have become the whipping boy in the global warming debate. Initially livestock farmers were cited as the main cause of global warming, until more research and common sense showed a slightly different picture.
Mining the earth for fossil fuels like oil, gas and mineral extraction was found to be a major contributor. In the UK, the destruction of peat was also very harming, and some of this activity was linked to the Forestry Commission’s tree-planting policy, which shows how short-term policies and lack of a complete knowledge base can distort the picture.
An informative report has recently been released by the independent dairy specialists Kingshay, showing how to measure levels of carbon stored in grassland soils. Quoting the author of the report, Sarah Bolt: “Every tonne of carbon stored is equal to 3.67 tonnes of CO2 equivalent which is not being emitted into the atmosphere.”
Following on from this, it was particularly interesting to see which conditions were most suitable for soil organic carbon retention. It was found that fields which were reseeded using over-sowing or direct drilling, had higher levels of soil carbon than those which had been cultivated or ploughed. This could impact organic farming itself, together with plant production systems which rely on ploughing, not only to plant crops but to control weeds.
Another key finding was of great interest, namely that soil carbon tended to be highest in permanent pasture and in grass leys, once planted, soil carbon increased each year after they were sown and left in place. Farmers can thus build up carbon in the soil, as well as producing food; methane from livestock, initially heavily slated, is a far less harmful gas than CO2, as it has a short life of ten years and can be absorbed back into the soil, particularly where grazing is taking place. It also has a place as a future fuel, powering ships and heavy machinery. Very importantly, there is also a thought that if farming remains of a consistent size, same land use and animal numbers, methane output is not increasing.
I bet farmers are now thinking of a money stream – carbon offsetting. Fortunately or unfortunately, there’s a simple principle with this; payments will not be for the status quo but for a long-term improvement. Currently carbon offsets are linked to projects to reduce deforestation in Brazil, rather than smaller farm projects in the UK, but times can change. Normally it’s the arable farmers who are in the money, getting the grants to take out hedges and then to put the hedges back for
example. Farming used to be mixed, and for centuries corn followed the Norfolk four-course rotation – two cash crops followed by two crops to feed livestock all year round, turnips, grass and clover for example, thus manuring the fields with cattle dung.
When chemicals and pesticides came in a big way in the early ’70s, mixed farming went out of the window, and it was corn, corn, corn. We now know that this caused soil erosion, carbon depletion and had a dire effect on insect life. Hopefully this practice will gradually change, and manure that can be spread from livestock farming onto arable fields, will be sold rather than given away.
It’s important to provide stable habitats. Every time a construction project takes place, it leaves the residual occupant with nowhere to go – homeless. Wild creatures are unlikely to thrive, or even survive under such conditions.
Habitat destruction has had a major impact on one of our bestloved Wind in the Willows’ friends,
Mole, though Ratty is still doing all right. Badgers’ dens are protected, even though they are major soil movers, but the poor mole has been poisoned and trapped for making a far smaller heap of earth. Mole hills were one reason fields were rolled in the spring.
Now there are few mole hills, and it’s been found better to preserve the air in the soil, to give the roots room to spread, and the worms to go about their business without being squashed. Interestingly there are no moles in Ireland; they didn’t survive the last Ice Age, and a company that tried to sell mole-frightening equipment to frighten away the non-existent moles was laughed into court. Moles used to suffer an appalling death through strychnine poisoning which also poisoned badgers and foxes who preyed on the dead moles. Golf courses with their smooth green runways will not tolerate a single mole. I have only played golf once, but it was with the Wiltshire golf champion. His exasperated comment
was: “If I’d known you were going to lose all my balls, I’d have brought my second best ones.”
A few mole hills might liven things up and give an absolute amateur a sporting chance. It would be great to save the moles!
In a dry spring, we used to gain great satisfaction working late into the night, rolling and chain harrowing the fields. We now gain far greater satisfaction seeing the cows grazing the fields, producing a tillering effect, which will increase grass growth through the season with less fertiliser inputs. Rolling was probably causing destruction to the nesting sites of ground nesting, so leaving it in the shed can be a win-win situation.
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