Agriculture Reference
In-Depth Information
meadows to pasture, and put the unregistered pasture over to hay. That way I would be
paid for carting fertility and organic matter from the unregistered area to the registered one.
After a few years I would swap everything over and get paid for carting it all back again. A
regular switch over from arable to ley every ten years or so would achieve the same result.
A more sophisticated regulatory system could no doubt stop this kind of scam taking
place on a single farm, but it would be harder to account for traf fic of soil carbon
throughout a region or a nation. Farming, and especially livestock farming, involves mov-
ing nutrients around, and there is little point in measuring carbon levels at one point without
taking stock of what is happening everywhere else in the system. Where there is only vol-
untary adherence to an accreditation scheme, the farmers who have an interest in joining
will be (a) those who manage to acquire the most manure, feed, hay or whatever other or-
ganic material is available - but who may not be adding anything to the collective wealth
of organic matter; and (b) those who convert from arable to grass.
To an extent (but only to an extent) this is a zero sum game. A recent paper by a Dutch
agronomist, G van der Burgt, takes a 'whole systems' approach to the prospects for car-
bon sequestration in the Netherlands. He and his colleagues conclude that there is scope
for increasing the organic matter by 0.2 per cent in individual arable fields throughout the
country but:
At national level … the situation is completely different. Compost, being an external source at farm level,
is an internal source at national level. If the increase is to be realized with compost only, the need is 8.3 million
tonnes per year. Total Dutch production at the time is 1.5 million tonnes per year, and this is already used in or
outside agriculture for soil improvement. Other organic sources are not easily available.
As for grassland, the situation is similar: 'As mentioned before there are no substantial
external sources of carbon - organic materials - available.' And in any case, with an av-
erage of 4.3 per cent organic matter, most Dutch grassland is already fairly high, no doubt
owing to the vast quantities of biomass imported from abroad. Taking agriculture as a
whole, the paper concluded that any increase in soil organic matter would be 'quantitat-
ively very limited compared to the national CO 2 emission'. 70
The situation is similar in Britain. Most existing organic materials already find their
way into the soil, the exceptions being a small percentage of the sewage, most food waste,
slaughterhouse waste, about 580,000 tonnes of poultry manure (burnt for energy), com-
postable paper, and whatever green waste is burnt needlessly or landfilled. 71 There is room
for improvement in recycling these items, but by comparison to our greenhouse gas emis-
sions, the soil carbon improvements derived from them would be negligible. Scientists
from Rothampsted have argued that if more of the manure currently deposited on grazing
land were incorporated into arable soils, a higher proportion of the carbon would be se-
questered. However, the potential gains in soil carbon are small, little more than a quarter
 
 
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