The Small Farm Future Blog

No diesel, no worries

Posted on June 24, 2013 | 8 Comments

Like every successful serial, Small Farm Future left its audience on an exciting cliffhanger last week – would the next post involve a feature on my diesel bills or on an article in the Aberdeen and Northeast Scotland Family History Society Journal? Well, all is now revealed – I’m going with the diesel bills, so you’ll just have to restrain your impatience for the Scottish history…

Last year I used 110 litres of diesel in my tractor, and a further 20 litres of petrol in hand operated machinery (rotovator, chainsaw etc) – the energy equivalent of about fifty 25kg sacks of potatoes. It’s not a huge amount, but actually it’s more than I’d have guessed and I’m not completely happy about it given how relatively unproductive the farm was last year. I reckon at least 10% of it was used in pointlessly driving between my house and the farm, and a fair whack of the rest was used in pointlessly cutting grass that would have been better grazed but for our inability to live onsite and look after the animals…but I won’t belabour that particular point any further just now.

Anyway, in future years I’ll be looking at ways of reducing the fuel bills, but to be honest they’re still quite small – on average, roughly equivalent to a family of four driving from Bath to Leicester and back in a family car. I’ve become slightly less purist about using agricultural fuel than I used to because I think there are many greater energy culprits in contemporary society than poor old market gardeners, among which the large number of unnecessary car journeys is pretty high on the list. A lot of people interested in alternative farming seem to baulk at agricultural machinery for various reasons, perhaps principally because it just doesn’t seem to fit in with the romance and mystique of working nature’s good soil to produce healthy food. And generally speaking, I think it’s true that the larger the machine the more alienated the farmer tends to become and the more damage s/he can do, though that’s not always necessarily true. But quite apart from the impossibility of any farmer ever making a living without using machinery, I just don’t think machinery use by market gardeners is that big a deal environmentally – should a low fuel/high labour economy emerge we could easily cut it out without substantially altering how we farm in a way that modern arable farmers couldn’t. I’ve made this point quite often to people I talk to, but it always comes out sounding a bit defensive, even though my conscience is pretty clear about my agricultural fuel use. Honestly it is. Dammit, why doesn’t this ever work?

Anyway, moving swiftly on one argument you sometimes hear is that large-scale modern arable farming is more efficient than a countryside full of yokels like me pottering around on our antiquated old tractors. A few years ago I did an energy input-output analysis for agroecological market gardening as compared to modern arable/industrial farming to look at that issue, which is available here. I think it’s useful to do analyses like that in order to create some kind of benchmarking of different methods, but I’m becoming slightly less interested in them than I used to be – there are so many perversities of the contemporary economy that disadvantage small-scale farmers against large-scale ones, and so many good reasons to be developing small local mixed farms, that some fancy analysis showing big farms can produce more food calories per unit energy input is really neither here nor there in my opinion, even though it’s something that small-scale farmers do need to think about.

Another argument you frequently hear is that local food and food miles are a red herring, because long-distance transport is very efficient and adds little to the embodied energy of our foodstuffs. It doesn’t seem widely acknowledged within this argument that however efficient long-distance transport is, it’s less efficient than no long-distance transport at all. Of course, it may be possible to show that the energy costs of long-distance transport are offset by the lower costs of producing something in some far-flung place (like the old chestnut about tomatoes from Spain), but again there are so many questionable assumptions implicit in this, one of which is that ‘efficiency’ should be a primary goal in the food system. I’d argue on the contrary that there are a lot of good reasons why we should grow tomatoes (as efficiently as possible of course, subject to more important goals) right where they’re eaten. This is partly a point about the way that markets work, which is where the Aberdeen Family History Journal comes in…but I’ve already said you’ll just have to wait on that one. Nice try though.

But is long-distance food transport really so insignificant? I spent a bit of time trawling the web for transport fuel use figures and did a few back-of-the-envelope calculations (not too many, I’m losing interest in this topic, remember…) The kind of figures I came up with were that a litre of fuel would move a 25kg sack of potatoes 43km in a car, 72km in a plane, 594km in a big truck, and 29,000km in a big ship. Now suppose I grow potatoes and green beans and sell them locally – let’s compare that with potatoes grown in Holland and transported here to Somerset (about 170km by truck and 500km by ship), and likewise with beans grown in Kenya and transported here (170km by truck and 10,500km by plane). Just for now, I’ll assume that inputs and yields are the same in all three countries, but we’ll come back to that. The table below shows some calculations for energy use on farm, in transport and in embodied transport energy (ie. the energy sunk in the manufacture of trucks, ships, tractors etc.) Energy measures are usually given in figures such as megajoules  or kilowatt-hours which don’t mean a lot to most people, so here I thought I’d use the more agriculturally-appropriate measure of potato sacks (ie. the energy/calorific value of a 25kg sack of potatoes: 93 MJ). So the table shows the energy used in growing and transporting one tonne (40 sacks) of potatoes

The embodied energy is pretty insignificant, though arguably my ‘methodology’ such as it is (ie the bottom quarter of the envelope) underestimates it. But the long-distance transport costs pretty much match the on farm costs, mostly by virtue of the 170km truck journey rather than the 500km ship voyage. So maybe these costs aren’t so insignificant after all. I wonder how much trucking is taken into account in criticisms of the food miles concept – Ford Denison for example writes that “Transportation of food is not the main problem….Over large distances, transport by ship, barge or rail is so energy-efficient that it adds little to the energy cost of food” (Darwinian Agriculture p.13), which looks like it might be true according to my figures above, except that if it’s trucked any significant distance beyond the port or the railhead then the argument breaks down. By my calculations, although trucks are much more efficient than cars, their use still adds a fair bit to the energy bill.

Running some similar calculations for the beans yields the following table in relation to a tonne of green beans.

Er, so local looks best for beans.

According to my tables, then, in order to justify long-distance imports on the grounds that the overseas producers have superior energy efficiency, the Dutch potato-growers would have to be more than twice as energy efficient as me, and the Kenyan bean growers more than 1,600 times. Are they? Possibly. But as I previously mentioned, there are so many other good reasons to foster a local small-scale agriculture that I’m not sure it matters that much.

I may have got these figures wrong – I knocked them out with my calculator late at night over a couple of glasses of Pinot grigio from, er, Australia – so I’d be interested if anyone has some more rigorous data to hand. But unless my figures are corrected, I don’t propose to worry too much about the modest diesel use on my holding. Which, as I mentioned above, I don’t anyway. At all. Really and truly.