I’m currently working on two pro bono projects at the moment. One is to help Martin Dewhurst source items for his Saharawi refugee camp gardens project New Dawn Rovers. The other is creating an educational panel on soil structure for the undercroft at the Linklater Pavilion in Lewes.
Both of these have involved me in a lot of background research – into Permaculture, into how effective organic techniques can be and how the hegemony of the World Trade Organisation makes it difficult to progress towards a sustainable future.
So recently I’ve come across a few killer stats that should make us all sit up and take notice.
They both stem from the fact that what we have come to think of as “conventional” agriculture only works in an era of cheap (or at least reasonably priced fuel) it depends on diesel to move the tractors around and chemically produced nitrate to grow the crops. This also has the effect of beating up the soil structure making it more prone to erosion. This deterioration of the soil structure is already concerning conventional growers – some I know from interviews on the Growing Jobs project have retained organic techniques of soil husbandry after a flirtation with organic growing for the supermarkets. We’ve also heard the UK Government’s chief scientist on the Today programme talking about soil structure – a sure sign that there must be a problem otherwise why would he be there?
But the two killer stats are these.
1) The CO2e footprint of conventionally produced crops is 40% higher than organic. Mainly due to the saving of energy to produce chemical nitrates. Figures from the long running Rodale Institute farm trials.
2) The more organic matter in the soil the better it retains moisture. Each 1% of organic matter in the soil will retain 168,000 litres per hectare. That’s of course hard to visualise. What it means is 4 cubic meters for a standard 10 pole allotment or 14 kilos per square meter. So 5% organic matter in the soil will hold 70 kilos of water per square meter. Substantially more than the body weight of a model like Kate Moss.
The third key fact is the ability of organic agriculture to sequester carbon back into the soil. About 500 kilos per hectare per year. This is not just through the application of compost but also due to the re absorbtion of roots from clover leys etc. IN fact organic practices currently produce soil carbon levels 28% higher than conventional methods in Northern Europe and 20% higher for all countries studied.
The ability to rebuild soil is critical given that the normal level of soil formation is 0.2 tonnes per hectare where the loss of soil by erosion is 2-10 tonnes per hectare per year (40 in North America)
Yields are also considerably higher than conventional in drought condidtions due to the moisture retention.
Our challenge to make agriculture sustainable is to get the right balance between organic and science to feed populations with less transport and fossil fuel inputs such as fertilisers.
There’s a lot of work ahead of us to mainstream organic husbandry – although to some extent the oil price is nudging us in that direction – at least in the UK.
That’s enough for now – we’ll look at some gardening next