A small experiment

I’m planning to start running what I hope will be a long-term experiment in different methods of organic vegetable growing, and I’d like to invite comments on it. If you can suggest ways in which the experiment could be improved, please let me know now before I embark upon it!

I’ve written a brief outline of the experiment under the grand title of the ‘Vallis Veg Small Scale Horticultural Trial’ which is also available on the Research and publications page, so I won’t repeat the details here. The basic point is that in an ideal world it would be nice if each garden plot could produce huge quantities of food, while requiring virtually no human labour or other resource inputs, and with no damage to the soil or the environment.

Back in the real world that’s not so easy to achieve – and don’t let anyone tell you otherwise! There are likely to be tradeoffs between various desired goals, and I doubt that there’s any such thing as a perfect growing system that optimises all of them. I’ve mentioned in previous posts that different authorities offer quite a number of variants on the theme of how to maximise fertility inputs while minimising tillage and labour, but there doesn’t seem to be an awful lot of convincing data around to evaluate the various claims. This is something that I hope I can help correct with the proposed experiment. If nothing else I ought to get some nice vegetables, improve my fitness through prodigious feats of double-digging, and do my bit to ward off the recession by providing some welcome business for soil testing laboratories. But if you can think of better or different approaches that I should be pursuing, I’d be grateful to hear your thoughts.

7 thoughts on “A small experiment

  1. Hi Chris
    lots to comment on here.
    Dowding describes his trial in his ‘Vegetable Course’ book and the results are more detailed than the magazine article. He says that the dug beds start of more slowly but catch up as the season goes on. There is no mention of whether they out yield the undug beds for very late crops. The list of crops is also more detailed, and more of there are more examples where dug yields are higher. His experiments use around 2 inches of compost a year. A better comparison would be his undug trial, versus a double dug rotation that uses 4 inches of compost incorporated into the soil, and 1 inch surface laid in year one, and then 1 inch surface laid for each of the next three years. This is much better practice, and I suspect would out yield the undug beds, especially on heavy soil.
    I have put quite a bit of thought into this, and am trying to combine a sustainable grain growing element into a Jeavons style system. There is a short version of this in Permaculture Magazine, but there is much more detail in my Vegetable/Grain design which you can read here http://sustainablesmallholding.org/diploma/project-7/project-8/
    Patrick Whitefield was right, we do have much in common.
    Regards
    Deano

  2. Hi Deano
    Thanks for that – I’ll follow up on those leads. Hope to stay in touch with you about this.

    All the best

    Chris

  3. Fantastic experiment Chris! In your outline you mention
    “Jeavons plots: rotavating followed by double digging”

    but from ‘ The sustainable veg garden’ pg31
    Jeavons/Cox say
    ‘A rototiller destroys the earthworms and other soil creatures… it also compacts the subsoil and destroys the soil structure.’
    so maybe the Jeavons plots should be just double dig? I don’t have the how to grow more veg book to hand to see if Jeavons says anything different in that.

  4. Thanks for that James. You’re probably right that ideally I shouldn’t rotavate the Jeavons plots, but it would only be in the first year to get rid of the ley. I may just mulch it in the first year as per the Dowding plots, or dig it by hand if I’m feeling energetic enough! I think the first year’s results will have to be disregarded anyway in relation to establishment issues.

  5. Hello Chris,

    I’ve just read your outline of the experiment and it looks excellent to me. If you need any further encouragement to do it I’d say it’s one of the most important projects I’ve heard about for years. A couple of points.

    I wouldn’t include a polyculture comparison. This is as big a question in itself as the soil/fertility management question you’re asking. It deserves a separate experiment with the same degree of replication as you’re putting into your main question here. All it will do as it is, I feel, is to complicate things for no really useful result. I could go on but I won’t.

    Another smaller point I’d like to make is about your equation of bare soil with erosion potential. I don;t think this is valid. Undisturbed soil, especially if it contains in situ roots of the previous crop, is much more resistant to erosion than disturbed. eg a winter stubble is much more resistant to erosion than a winter wheat field with little plants which fail to cover or hold together the fine-tilthed. Yet the stubble would be considered bare soil and the overwintering cereal ‘coverd’.

    Anyway, presumably you’re going to actually measure erosion, or at least assess it visually, rather than simply count up the months of ‘bare soil’ under each treatment.

    All the best, Patrick

  6. Thanks for that Patrick – very useful comments, and an interesting point about soil coverage. I take your point about the polyculture component…I need to think about it a bit more.

  7. Pingback: Old posts from “Darwinian Agriculture” blog at the University of Minnesota

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