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Janet Sprent, whose research I've admired for decades, reviewed my book in the Bulletin of the British Ecological Society. I couldn't find a web link to the review. She writes that "not all readers will agree with the arguments against these holy cows [perennial grain crops] but they deserve serious attention." Given our shared interest in nitrogen fixation, she was surprised by the lack of discussion of nitrogen-fixing cereals. But the book was already long enough to keep her "fully occupied on a 13 hour flight."

I probably could have lumped nitrogen-fixing cereals with C4 rice: both are big enough changes that we can't assume they have already been "tested and rejected by natural selection", but both may be "beyond anything humans today could design and implement from scratch." I may have to modify the latter statement for C4 rice after seeing what progress they've made at the International Rice Research Institute, next month, although copying other C4 plants isn't the same as designing a new photosynthetic system "from scratch." Making nitrogen-fixing cereals might be even more difficult, however, as I have discussed on my other blog.

Chris Smaje, a regular commenter here, reviewed my book for Permaculture Magazine (link to docx file here) and separately on this blog, Small Farm Future. Both reviews are examples of the kind of thoughtful discussion I hoped to generate with the book. He wrote:

"I suspect that it's ultimately impossible to create any kind of agriculture that can usefully be regarded as 'natural', but the further we depart from it the more we're flying blind..."
Similarly, I wrote (p. 74):
"the more we depart from nature, the more we enter unexplored territory, with possible unknown risks."
Still, the quantitative comparisons in Chapter 6 are consistent with my theoretical argument that it may be possible to improve on the overall organization of natural ecosystems. For example, crop rotation may be a good idea, even though natural ecosystems rarely have such dramatic changes in plant species from one year to the next. In contrast, Chapter 5 argues that making simple, tradeoff-free improvements in individual-plant traits like drought resistance will be much harder, even with biotechnology. This is because natural selection has tested individual traits competitively against alternatives, over millennia. Meanwhile, no natural process has consistently improved overall ecosystem organization on that time scale -- see previous post.


The knack that I have of over-estimating my capacity for original thought has given me a lot of amusement over the years, and the comedy is only heightened by unwittingly using one of your own arguments in order to criticise you. However, since I wasn't really criticising you I hope I can be forgiven.

Regarding the point about deurbanisation on my blog and in your email, I think one of the problems is that the lifestyle of rural people in wealthy countries like the US and the UK is basically the same as the lifestyle of urban people, only with less resource efficiency, whereas the lifestyle of rural people in many poor countries basically sucks. Therefore we have few extant models of what a sustainable and convivial rural lifestyle might look like. I think we urgently need to have a debate about this, but even to raise the issue invites the kind of 'retro-romantic' caricature that was recently directed at me on my blog. I'd be interested in a detailed deurbanisation plan too, though I suppose there's a danger of producing utopian blueprints (I wrote a short article about some of these issues called 'The ungreen city or the polluting countryside' in Significance magazine, Vol8 No2, 2011).

Interestingly, here in the UK the town planning movement during the 1930s developed the idea of 'green belts' around small towns as places that would be kept free of urban spread so that farmers could grow food for local consumption in the towns. As per the discussion we had here on your blog a while back, it's deeply ironic that the way that's played out is that 'green belts' are now used to prevent virtually any kind of residential developments associated with farming, with the result that the countryside is dominated by large-scale, machinery-intensive agriculture which is not oriented to its locality at all.


We agree that random changes to a natural ecosystem that has shown its sustainability (by persisting over millennia) may undermine that sustainability. But any major increase in food export from that ecosystem moves us into unknown territory anyway, where past sustainability doesn't predict future sustainability.

When research in natural ecosystems shows that feature X (species diversity in space, say) contributes to some aspect of performance useful in agriculture, let's try X in agriculture and see if it delivers the same benefits. But let's also try variants not seen in nature, like crop rotation.

My problem is with arguments of the form: "natural forests have three layers of leaves and they can persist without external inputs [as long as we don't harvest anything]; therefore orchards wouldn't need inputs if they had three layers of leaves." I doubt that many people would agree with this statement in this explicit form, but implicit versions are common.

Thanks for that Ford. Sounds right to me, and I must admit my enthusiasm for the forest gardening approaches much favoured in permaculture has waned somewhat for exactly that reason. I wrote a bit about the issue more from a labour/economics point of view than an ecological one here:

But maybe there are still things to be said for incorporating more trees into agriculture. The research going on at Wakelyns seems to be turning up some interesting results.

In regards to Chris' comments that "we're flying blind" and in "unexplored territory," I am struck by how this also applies to Darwinian evolution. Certainly, over long periods of time, there appears to be a wisdom in what nature has done, but it all comes down to undirected trial and error. Surely humans, with our well evolved brains can do better than flying blind in designing agricultural systems, as complex as they are?

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