HOLISTIC COWBOYS AND CARBON FARMERS - MEAT: A Benign Extravagance - page 242

able by organic standards, but lower than compared to conventional chemical monoculture,
and it is hard to find results for soil carbon content in reports of these experiments. 51
The level of carbon sequestration that Jones thinks is generally 'achievable by land-
holders practising regenerative cropping and grazing practices' is 0.15 per cent of the soil
turned to carbon per year - the equivalent of adding 23.1 tonnes of carbon to every hectare,
each year. This is broadly consistent with another planet-saving statistic that she likes to
repeat, that 'it would require only a 0.5 per cent increase in soil carbon on two per cent of
[Australia's] agricultural land to sequester all of Australia's emissions of carbon dioxide.'
(If this seems implausible, it is worth bearing in mind that Australia is huge and under-
populated: Jones is talking about an area half the size of Britain's agricultural land for a
population about a third the size of Britain's.)
Twenty three tonnes per hectare is about 20 times the amount of carbon that the IPCC
considers can normally be gained from a variety of land use practices, such as minimal till-
age or pasture improvement. 52 Dr Jones' projections seem to be hypothetical; I could find
no evidence of trials showing that this level of carbon sequestration had been achieved on
any regular basis. The mainstream guru of carbon sequestration, Rattan Lal, estimates that
the USA has the potential to sequestrate between 122 and 357 million tonnes of carbon per
year on 491 million hectares - about ten per cent of the world's arable and grazing land. 53
This is way short of Dr Jones' estimate of 185 million tonnes from 8.9 million hectares; the
rate of sequestration anticipated by Jones is 40 times the average anticipated by Lal, who,
by mainstream standards is a soil carbon 'optimist'. Moreover, this rate of sequestration
cannot be kept up indefinitely, since soil, like forests, reaches a state of carbon saturation -
it only offers humanity a breathing space while we find an alternative to fossil fuels.
So who is right? Jones claims that 'sequestration rates under regenerative agricultural
regimes may be quite a bit higher than estimated by current models', in other words that
the modelling system used in Australia and the UK, called Roth C, developed at the UK
research institute at Rothampsted, is wrong. The Roth C model, Jones claims, 'is based on
the assumption that most carbon enters soil as 'biomass inputs', that is from decomposi-
tion of plant leaves, plant roots and crop stubbles.' 54 But it does 'not take into account the
process of humification of root exudates or contributions from mycorrhizal fungi.' 55 The
role of these fungi has risen in scientific estimation since 1996 when the USDA researcher
Sara Wright discovered the substance glomalin, a protein produced by mycorrhizal fungi
that 'may account for one third of the organic carbon stored in agricultural soils'. 56
The process is explained more clearly in an article about Jones' work that appeared in
the Australian magazine ECOS : 'Through photosynthesis, the activities of symbiotic bac-
teria and fungi, associated with roots and fed by the sugars, enable the exuded carbon to be
combined with soil minerals and made into stable humus which locks the carbon away …
'This can't happen where farm chemicals kill the essential soil microbes', says Dr Jones.