Agriculture Reference
In-Depth Information
system, whereas there was barely any increase of carbon in the chemical system. This is
by no means negligible, but at that rate (if it could be maintained) it would take 56 and 67
years respectively to reach Yeoman's projected 1.6 per cent increase. Global warming, by
most accounts, will be well under way by then.
46
Nonetheless, the fact that organic, minimum tillage and grazing systems all score quite
well in mainstream literature does suggest that Yeomans might be on the right track. Unfor-
tunately, the only evidence he provides to show that the levels of carbon sequestration he
proposes are actually achievable is a single eye witness report of his father's soil building
prowess:
Sir Stanton Hicks writes in his book
The Nutritional Requirement of Living Things
:
'After three years he (PA Yeomans) was able to demonstrate that black soil had formed
to a depth of 12 inches where scarcely any soil had previously existed on this rockstrewn
countryside. Thousands of farmers and many distinguished visitors from overseas have
witnessed the results of this transformation of a barren tract of land into a parklike region,
carrying fine livestock all year round.'
47
At no point does Yeomans produce any before-and-after measurements of carbon on
either his land or anyone else's. I have witnessed soil of the kind he describes built up on
land that had previously been stripped of its organic matter, for example by growing and
mulching comfrey - but only on a small scale, in a temperate landscape and probably with
considerable inputs of compost. Much as those of us with organic or permaculture leanings
would like to believe his theory, more credible evidence would be necessary to prove the
point.
Graham Harvey's book on the carbon fields of Britain doesn't shed much light on the
matter either. He cites the 1.6 figure, which he credits, not to Yeomans, but to the Car-
bon Farmers of America, though they feature it in an excerpt from Yeomans' book on their
website. Harvey prefers to rely on another Australian, Dr Christine Jones, who runs an
accreditation scheme, which currently has a pilot project in Western Australia generously
paying farmers 90 Australian dollars (about 57 US dollars) for every tonne of carbon their
soils absorb. The fund is subsidized by Rio Tinto Coal, a subsidiary of the Anglo-Australi-
an mining company Rio Tinto - which rather scuppers Yeomans' notion that the fossil fuel
industry wants to divert attention away from carbon sequestration.
48
I got off to a bad start with Dr Jones when I picked up on this comment in Graham Har-
vey's book: 'Christine Jones … calculates that raising the level of soil organic matter by
one per cent across just 15 million hectares of land would capture the carbon equivalent of
the earth's total greenhouse emissions.'
'Some mistake, surely?' I thought when I read this and turned to Dr Jones' website,
where I found this variant: 'it would only require a one per cent increase in soil carbon
on 15 million hectares of land to sequester 8Gt (billion tonnes) of carbon dioxide, which
