Regenerative farming is an approach to farming that aims to allow the land, the soil,
water, nutrients, and natural assets to regenerate themselves, as opposed to
conventional approaches to farming that can deplete these natural resources.
Recently we have watched two excellent films showing enthusiastic farmers using
the approach, Six Inches of Soil, and Rachel’s Farm, which was on BBC and is
available on iPlayer. There are many good features in these films, but there are a
couple of points about which I was less sure. There is a claim that contrary to
conventional opinion ruminants are not responsible for the methane that exists in the
upper atmosphere. In Rachel’s Farm Rachel goes on a course in which the lecturer,
Dr Walter Jehne, asserts that the methane emitted by a ruminant when it belches is
rapidly neutralised by the hydroxyls, OH, given off by the surrounding grasses. I
know little chemistry, but have gleaned the following from the web.
It seems that everyone agrees that OH is a highly reactive gas that acts like an
atmospheric detergent, breaking down methane and other gases, but the
conventional view is that the process occurs in the troposphere 6 – 19 km above the
earth’s surface. In contrast in Dr Jehne’s theory the process occurs before the
methane leaves the vicinity of the cow because there is there an abundance of OH
molecules created by the breakdown by sunlight of water molecules emitted by local
plants.
I have tried to find evidence for this theory but there is no scientific paper in the
places I rely on, Google Scholar and Web of Science. Dr Jehne is a scientist who
retired from Australia’s national science agency CSIRO in order to work on
regenerative farming, so I contacted CSIRO to ask them about the theory, but have
not received a reply.
The other point on which I need help is the claim that when farmed regeneratively,
soil is a continuing carbon sink. I can see this working while the soil is regenerated
and soil carbon levels increase, but long-term, continuing absorption of carbon would
surely require soil levels to rise. But perhaps this is what happens?
Help appreciated! Please send comments to r.m.sibly@reading.ac.uk
Richard Sibly
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