Of agricultural productivity: or, lies, damned lies…

…and a brief rumination on statistics.

First up, this recent post by Elizabeth Royte about city agriculture, claiming that 20% of the world’s food is grown in urban farms. Cue appropriately incredulous responses from commenters below the post questioning the figure. Think about it. Roughly half the world’s people live in towns, so assuming urban agriculture feeds only urban people, the suggestion is that around 40% of the food eaten in towns is grown in them. Hmmm.

In response to the doubters, Royte refers to this report from the Worldwatch Institute, whence the figure derives. The report states “Roughly 15–20 percent of the world’s food is grown in urban areas” without further elaboration or citation. So not much traction there. Put it this way – about 33% of global land area reputedly is devoted to agriculture, while the splendidly named GRUMP project reports that towns account for 3% of global land take. Let’s suppose that a generous 15-20% of those urban areas is devoted to urban agriculture (where do I get that figure from? Well, that’s for you to ask and me to know), that would imply urban agriculture is around 14 times more productive per acre than rural – which to be honest may just about sneak within the bounds of the not-totally-incredible, bearing in mind the different agricultural styles and scales involved. Not totally incredible, but not very likely – especially since my 15-20% urban agricultural land figure is surely an overestimate. And I doubt much urban agriculture is devoted to the meat-grain nexus which supplies much of the global, and certainly urban, plate.

Maybe the Worldwatch figure refers to proportion of production by value – all those fancy micro-salads and strawberries grown in vertical farms and the like. Still sounds like an overestimate to me, though. Or maybe the definition of ‘urban’ – which in many global datasets encompasses settlements of only 10,000 souls – includes peri-urban areas of small towns where undoubtedly a lot of global agriculture does take place. Or, as someone pointed out in response to Royte’s article, which referred to a figure of 800 million people globally involved in urban agriculture, perhaps it was assumed that all of these people produced all of the food they needed.

Another commenter wrote “I don’t care about the numbers being correct I’m just glad to see a movement towards nature”, and I’ll happily drink to that. There are endless reasons beyond mere productivity why supporting urban agriculture makes sense. The only rider I’d add is that there are plenty of people around who are eager to beat the drum for urbanism in general, like him, and him, and them, because of ideological prejudice political opposition to rural life and peasant production. Presently these types have to content themselves with arguments about the misery of peasant existence and the environmental negatives of rural life (often tendentiously imputing the ecological costs of agriculture practiced in rural areas to rural people alone), but how much better it would be for them if cities could escape their moorings in the messy, quasi-natural ecosystems of the countryside and float off into a Futurist realm of pure self-sustaining urban humanism. And so I say unto you, beware that 20% figure as it begins its inexorable creep upwards in the burgeoning fantasy of human overcoming.

Talking of dodgy statistics, another one recently placed under the spotlight in an interesting article by my LWA colleague Ed Hamer1 is the oft-repeated figure that globally we need to produce 70% more food by 2050. As Ed points out, since global population is predicted to increase only by about 30% by that date it’s not immediately obvious why so much more food is needed. More meat for the masses perhaps? In any case, the figure seems to suit the position of the ‘new productivists’ who argue that we need a big biotechnological push in order to meet future needs, though equally one could argue that in order to provide 70% more food by 2050 we need a big political push to get more people into small-scale agriculture and support peasant farming. I wonder why that argument doesn’t get so much airplay? But, more importantly, according to Ed it turns out that the 70% figure comes from a modelling exercise concerning how much more food is likely to be produced by 2050, an exercise involving various unrealistic assumptions to boot. In other words, the figure involves a methodological error graver still than the classic social science fallacy of turning an is into an ought – turning a may be into a must.

Oh well, facts never really prove much anyway, still less factoids, and fictoids like the 70% figure least of all. So I plan to carry on farming my own humble plot as best I can – a peri-urban semi-peasant producing for myself and for others, more than what my land provided before I took it over, less than what it could perhaps provide if it were all ploughed up for cereals, but probably a better mix of stuff overall. Live those contradictions…

References

1. Hamer, E. 2014/15. Feeding the nine billion. The Land, 17: 31-3.

Turkeys do vote for Christmas: A Small Farm Future Election Special

I don’t make a habit of discussing party politics on this blog, but I guess a few comments on the recent British elections are in order.

Farming was basically a non-issue in the election, but the result has certainly disproved an old agricultural adage. Do turkeys vote for Christmas? Well, now we know that yes, sometimes they do. I’ve often despaired of the way that people so often vote out of unenlightened self-interest. But now that the people of England have voted out of unenlightened non-self-interest I find that my despair is not lessened. There was a turnout of 66.1%, with 36.9% of that figure voting Conservative. I think it’s safe to assume that more than 24% of voters will be hurt by Tory policies. Turkeys. Christmas. Why?

Maybe this story will help shed some light. I make a regular visit to a farm just to the south of Bristol. My journey starts in Frome, a town long past its industrial prime but enjoying a second lease of life as a quirky, arty, post-industrial sort of place. During the election campaign, Frome was green on black: a massive preponderance of Green party political posters against the darkness of the houses. I soon leave Frome and drive ten miles or so to Radstock, and ten miles or so out the other side. These twenty miles of countryside were blue on green: Conservative party posters against the green of the fields. Radstock itself was (mostly) red on black: Labour party posters in the houses, Radstock being a somewhat less post-industrial town than Frome, its last coalmine closing only in the 1970s.

Take a look at the electoral map of the country as a whole, and it seems my journey is pretty much a microcosm of national politics – Scotland excepted. Labour was the party of organised industrial labour, but this support base no longer exists, except in a few remnant and memorialising patches. Labour’s current leftism isn’t radical enough to appeal to the urban sophisticates of the postmodern city, and perhaps too radical to appeal to the regular middle class. But you would have thought that the Conservatives might have lost their support base too. We’re no longer a nation of toffs and aspirant working-class Thatcherites, after all. So those Conservative posters in the fields do puzzle me a bit. What are the Tories offering farmers that makes them so attractive, apart from a few sideshows like the badger cull that was so ludicrous it pretty much cost the Environment Secretary his job?

Partly perhaps there’s a grey area between farmers and landowners, with farming basically being a landowner’s hobby – and I can see that there’s much about the Tories to appeal to self-interested landowners. But I think it also comes down to political metaphor. We’ve become used to politics by soundbite, and maybe the Tories’ ones play better to an electorate long starved of an ability for extended political rumination: stability, hard-working families, fiscal prudence, self-sacrifice, immigrants, Englishness, all of which resonate in our sense of countryside and agriculture. A Tory-friendly press helps too. I think it’ll be a long, hard road to replace that narrative with a more credible one but I guess we have to try.

Oh well, there’ve been a few bright spots. In the simultaneous local elections, here in Frome every single one of the town’s 17 elected councillors came from the ranks of the Independents For Frome – surely an unprecedented result, and based on their solid good work over the last five years. And even the Death Star of Mendip District Council, though regrettably still Tory, now has three infiltrators from the Green Party within its ranks. The bigger national story is the astonishing result in Scotland for the SNP. It’ll be interesting to see how that one plays out, but perhaps the hopeful message is that an anti-austerity localist message can find a receptive audience given the right context. The relative failure of UKIP is also encouraging, the relative failure of the Greens less so. The farce of the first-past-the-post electoral system looms large in the face of the votes to seats ratio of the last three parties mentioned: perhaps the winds of change will have to start blowing on this one.

Meanwhile, it’s worth taking a quick peek at what the major parties did actually say in their manifestos regarding agriculture. Well, that’s easy in the case of Labour – virtually nothing, so perhaps those blue posters in the countryside and the red ones in the old industrial towns become more understandable. There’s nothing whatsoever in the SNP’s manifesto either, which makes it a bit harder for me to enthuse about their David v Goliath localism. The Conservatives say more – mostly about boosting the UK’s competitiveness in food exports and bringing back fox hunting. Not much succour for the small farm or the local food agenda there. It really is a landowner’s and agribusiness charter.

By contrast, there’s lots of stuff on agriculture that I can sign up to in the Green party’s manifesto and, er, in UKIP’s. The Greens were proposing a land value tax to partially replace income tax – quite right too, and long live Henry George. Though speaking of self-interest as I was earlier, as someone with a fair bit of property but not much income I’m not quite sure how this would have played out for me personally in the unlikely event of a Green government – their policies on a sustainable local farm economy look good on paper, but are rather vague. Weak support for farming coupled with an over-enthusiasm for land value tax could easily nail British farming to the wall. But the chances of the Tories introducing land value tax are precisely nil, so for now that problem is wholly theoretical.

As for UKIP – well, they’re surprisingly supportive of organic farming and other earth-stewardship approaches for a party that not so long ago was proposing to ban Al Gore’s Inconvenient Truth from schools. You’ve gotta give at least half a brownie point to a party that mentions rare livestock breeds in its manifesto. And though the EU’s farm subsidy gravy train is a soft target, they load, aim and fire at it appropriately enough. Not quite sure who’d be doing all the hard work at the bottom end of the food system once UKIP had sent all the foreigners packing. But I must admit, I’m slightly drawn to their EU exit policy. EU agricultural policy is a real brake on retooling ourselves for a more sustainable small farm future, and exit would also have a salutary effect on all those little Englanders who consider Britain to be a cut above continental Europe – once we realised, too late, what an insignificant little country we really are and how much of our wealth is based on the unearned privilege of messing with other countries’ money, we’d have no option but to throw ourselves back on our own parochial resources, which would probably be no bad thing in terms of sensible agricultural policy. But if it came to a referendum, which I guess it will, I’m not sure I could abandon my internationalism enough to side with the nostalgic imperialist dreamers.

Bottom line message – roll up your sleeves, there’s political work to be done. It’s just that I’m not quite sure what it is. So perhaps instead I should forget about the politics and just focus on producing my veg as best I can. And maybe some turkeys too.

PS. …and talking of birds, I thought I’d put a new header image up since the old one of my farm was so out of date it bore little relation to present circumstances. So here’s a picture of starlings flocking over Vallis Veg’s winter treescape.

 

GM and the obfuscation of science: or, the denialist Mark Lynas

In my previous post, I mentioned the problematic way in which GM proponents tend to appeal generically to “the science” in support of GM crops, a point amplified by Ford Denison in his comment. Encouraging, being as Ford is a scientist…though not necessarily “the scientist”. Some of his own scientific work hinges on the complexities of the biological tradeoffs involved in trying to develop ‘improved’ crops that deliver on all the demanding traits humans ask of them. But as a social scientist, here I’m going to take a different tack and focus on some of the problems associated with making generic and normative truth claims (for example, of the form “…the science says that we should adopt crop x”) on the basis of the scientific evidence. There is, I think, a tendency in the GM debate to invoke science as metaphor (hard, objective, unarguable) in a battle with politics (soft, perspectival, debatable). So here for your consideration are five levels of obfuscation involved in generic claims that ‘the science’ supports GM crop technologies.

1. Peer review, only peer review.

There is, to be sure, a lot of nonsense out there on the information superhighway, so there’s something to be said for restricting your evidence base to credible sources, such as peer reviewed scientific journals. But in these days of ‘evidence-based policy-making’ (or ‘policy-based evidence making’ as some wags call it), peer review has assumed an evidentiary cachet whose weight it really can’t bear. I mean, they’ve even published a paper by an ignorant greentard such as myself in a scientific journal, so on the Groucho Marx principle peer review surely can’t be that rigorous…And in any case, there are plenty of peer reviewed journal articles pointing out the shortcomings of GM technologies, such as this one

2. Scientism

Ah, but that’s in a social science journal – not proper science at all. Social scientists put on all sorts of airs and graces, and even admit to not being objective. Proper scientific research is, as Peter Medawar explained, about the art of the solvable. It can’t answer questions like ‘Is treating vitamin A deficiency with golden rice an appropriate intervention in terms of social benefit?’ but it can answer questions like ‘was there increased morbidity in a treatment group exposed to golden rice compared to a control group?’ By ruling wider questions – policy questions, political questions – out of the purview of science proper, a lot of awkward issues around GM can be deflected. This manoeuvre is called scientism, but it doesn’t have an awful lot to do with science. It’s more a social ideology about the primacy of certain kinds of knowledge. GM plant scientist Pamela Ronald’s book Tomorrow’s Table about the errors of opposing GM is full of a gentle, patrician scientism which guides the reader towards the right kind of journals that will inculcate the right kind of views on GM. Ach, but absence of evidence is not evidence of absence…

3. False positives, false negatives…

Well, the absence of scientifically acceptable evidence (‘acceptable’, that is, in the sense of getting through peer review in the kind of journals scientism is prepared to acknowledge) against certain GM technologies isn’t total. But of course, as GM proponent Steve Savage argues, a peer reviewed journal article is only the beginning of a conversation about the merit of the research – the fact that it queries a GM technology doesn’t mean it’s right. Very true. Savage goes on to savage the failings of certain choice studies that question aspects of GM/biotech. But of course his strictures apply to studies finding in favour of GM technologies just as much as those finding against. Are findings reporting safe and beneficial results from GM technologies treated with the same level of critical scrutiny as those that find otherwise? The possibilities for publication bias in the scientific literature are legion. What we need is systematic reviews that attempt to address this. But I’m not sure what we need is what we’ve yet got. Still, here’s a study that reports statistically significant correlations between author affiliation to the GM industry and study results favourable to GM crops. Food for thought.

4. The discreditable practice of discrediting

With really high profile negative findings you can take the next step on the publication bias road and exert political pressure to get the study discredited and retracted. The retraction vultures have had their fill in cases such as the Pusztai and Séralini affairs, and are currently circling around the glyphosate cancer study. It’s not that any of these research findings are necessarily beyond reproach – it’s just that ol’ problem of publication bias again, if the papers that feel the methodological heat are systematically more likely to be ones to which the GM industry objects. The Séralini affair has now spawned an interesting secondary literature – including this analysis which argues that if Séralini’s methods are flawed then so are those used by Monsanto in studies reporting no raised rat morbidity. Eventually, I think, the truth will out. Meanwhile, I’m not inclined to put too much trust in the (often opaque) processes by which studies disfavoured by the GM industry lead to journal retractions. Why not avoid publication bias and legalistic interpretations of peer review by letting studies that pass initial peer review stand? In my eyes, the discrediting of studies that are sceptical about the merits of GM technologies is itself becoming discredited.

5. Denialism denied

Failing all of the above, you can simply dismiss opposition to GM crops as an ‘anti-GMO denialist myth’ as per Mark Lynas. The ‘denialist’ concept troubles me. Ironically non-scientific, it’s an “as everybody knows…” rhetorical strategy designed to circumvent debate and stigmatise one’s interlocutor. Thus has Edward Skidelsky referred to denialism as a “word that thinks for us”. I like his argument that “The extension of the “denier” tag to group after group is a development that should alarm all liberal-minded people. One of the great achievements of the Enlightenment—the liberation of historical and scientific enquiry from dogma—is quietly being reversed.” Spot on – there are instructive paradoxes involved in dogmatic appeals to ‘the science’ and in unreasonable appeals to reason in the GM debate, probably on both sides. I suppose in some contexts – Holocaust denial, climate change denial – ‘denialism’ does at least refer to the active denial of something that has manifestly happened. But what is it that GM ‘denialists’ are denying? Not that GMOs exist, or that they’re being grown. Nope, they’re just denying that growing them is a good idea. Of course, you can disagree with their reasons for thinking so. And indeed that’s what Lynas’s concept of denialism amounts to. GM denialists are people who disagree with Lynas and his ilk about GM crops. Well, two can play at that game. So henceforth I plan to refer to Lynas as ‘the denialist Mark Lynas’ on the grounds that he disagrees with me.

From Science to Society

In my humble opinion, both GM critics and GM proponents spend too much time arguing over what “the science says” about GM crops. The science is important for sure, but it doesn’t ‘say’ any single thing. And indeed, as eco-panglossian guru Stewart Brand sagely writes in his book Whole Earth Discipline, “nothing is fully established scientifically, ever”. Strange that in the same book he should later write “the science is in” in favour of GM crops.

Enough of this nonscience. Let us stop appealing to ‘the science’ just because it sounds grander and more objective than appealing to ‘the politics’. The issues around GM crops are political and sociological as much as scientific: the overuse of a handful of GMOs – thereby driving the rise of resistant weeds and pests, potentially transferring transgenes to wild crop relatives, and compromising human and ecosystem health – is a sociological issue. The fallacies around the notion that GMOs are pro-poor technologies are sociological in an even more fundamental way. And so are the affinities between GMOs and the neo-improver ideology of large-scale corporate agribusiness. I’m yet to be convinced that these are not all serious problems with existing GMOs, though I wouldn’t go so far as to say that they fatally undermine the possibility of useful GM crops in the future. But ultimately the debate ought to be about what kind of society we want, and therefore what kind of farming we want. It ought to be about how we can best solve problems like poverty and malnutrition. These issues are sociological and political, not just scientific. ‘The science’ on GM crops is, well…just the science.

GM & glyphosate: Rachel Carson (sort of) speaks…

Well, thanks to those of you who commented on my recent annual vs perennial grains marathon. I invited Tim Crews of the Land Institute to respond, and he said he might, but it looks like he’s decided not to. So I guess the whole thing goes the way of many academic debates before it: ‘you’re wrong’, ‘no, you’re wrong’. And only time will tell. Though I’m quietly confident that in fact it is me who will ultimately prove to be right – a conclusion to which my research has pointed with remarkable consistency over the course of my career. Meanwhile, I think Ford Denison may be writing something about the debate, so it’ll be interesting to read that (STOP PRESS: here it is).

Anyway, now it’s time to move on – and what better topic to choose than plant breeding’s Scylla to the Charybdis of perennial grain breeding? Yep, you guessed it – GM crops.

OK, OK, I know I vowed to avoid this issue – one that’s so balefully polarised as to make any kind of productive debate with the other side seem impossible.  On GM, I have engaged amongst others with the ingenuous, the angry, the emotive and the merely vapid without worthwhile result. No more, I have said solemnly to myself, no more. But there are some new angles to explore, so the time is right for just one more whirl. Well, two in fact – I need to descend slowly from the giddy heights of those multiple linked perennial grain posts, so I’m going to acclimatise to normal service with a GM two-parter.

Part One concerns glyphosate, which isn’t intrinsically linked to GM technology in and of itself – except that, well, it kind of is, on account of the fact that glyphosate-resistant crops constitute about 80% of the GM crops grown worldwide1. All the talk of golden rice, Hawaiian papaya, Bt cotton etc somewhat blinds us to that brute fact. So if there are problems with glyphosate, then basically there are problems with GM crops, at least as they currently manifest.

And it looks like there may be some problems with glyphosate. One that’s received a lot of attention lately is a possible link to raised cancer incidence, as reported in this study. But there’s another set of interesting potential problems which have been outlined by Thierry Vrain, a retired Canadian government agricultural scientist.

Vrain has set out his thesis in an open letter to the Canadian minister for health. I précis it as follows:

1. Glyphosate is sufficiently persistent and ubiquitous in the environment for it to find its way into the human body

2. Glyphosate’s main action is to interfere with an enzyme possessed by plants and some bacteria and fungi but not by animals, so it doesn’t have acutely toxic effects on people.

3. However, glyphosate does have a toxic effect on the microbial population of the human gut, and may therefore cause chronic human ill health through impeding normal gut function

4. Glyphosate also has chelating properties, which may result in reduced availability of trace metals essential to a healthy human diet

Well now, I don’t know if he’s right but it strikes me as an interesting line of argument – albeit one that’s quite difficult to prove without costly chronic morbidity studies, which I don’t believe have yet been undertaken. I can think of various reasons why Vrain’s fears may prove unfounded, but I don’t think there’s yet any conclusive evidence against – a trawl through the internet reveals various dismissive screeds about his views such as this and this, which for the most part ignore his actual reasoning in favour of generic appeals to the ‘science’ in support of GMOs, while ridiculing the discredited ‘pseudo-science’ that Vrain invokes.

I’ll say more in my next post about science, pseudo-science and the discreditable practice of discrediting studies. But when it comes to a scientist raising questions about the wisdom of a mainstream agricultural technology and then getting this kind of blowback from the technology’s proponents, I get a funny feeling of déjà vu. Doesn’t it all sound a bit Rachel Carson – vilified in her time for daring to raise even the possibility that there might be a problem with DDT, but ultimately proved right? Whether Vrain will turn out to be right or not is of course unknown, but if he is then given the ubiquity of glyphosate we have quite a problem on our hands. So I assume that everybody would support the establishment of rigorous, independent, long-term studies to look into the issue. Well, everybody but those with a vested interest in GM. Monsanto is already calling for the cancer study to be retracted. Now why would that be?

Let me just reiterate my point about independent chronic toxicity studies. GM proponents like Steve Savage and Graham Strouts have invoked the spirit of Rachel Carson to their cause, implying that GM crops and/or glyphosate are safer than the biotechnologies of yore and Carson would have supported them. As I’ve argued previously, this strikes me as a somewhat sneaky tactic to appropriate an environmentalist icon to their own particular agenda and thereby clothe it with the reflected legitimacy of her name. And, being dead, Carson conveniently lacks a right of reply. Well, I don’t have the temerity of Strouts to ventriloquize with such confidence what Carson would have supported, but given the nature of the battle over DDT I suspect that if she were alive today she might well be calling for rigorous, independent, long-term studies to investigate a possible association between glyphosate and chronic human morbidity. So I’d hereby like to invite Steve and Graham to gather together with me in homage to the spirit of the woman that we all revere and join me publicly in that call so that Vrain’s thesis can be tested.

Meantime, I think I’ll put my plans to incorporate glyphosate into organic farming on ice…

Notes

1. Or at least it did around 2008, according to this paper: http://www.agbioforum.org/v12n34/v12n34a10-duke.htm. If anyone has some more up to date figures, I’d be keen to see them.

Of Dr Jekyll and Mr Hyde

This is the fifth and last of my posts about my article ‘The strong perennial vision’1 and the response to it by Timothy Crews and Lee DeHaan2 (C&D). One of C&D’s characterisations of my argument is that “Focus on perennial grains detracts from more important strategies for achieving agricultural sustainability” and they go on to criticise me by saying that I offer “no data on trends in funding, literature published or cited to support this concern. Nor [do I] substantiate the perception that groups working on what [I call] the strong and weak perennial visions are competing for attention or resources”. So I’m going to talk about that in the present post, before offering a few concluding remarks to wrap the whole thing up.

With hindsight, perhaps I shouldn’t have pursued that particular line of argument – it’s not the most important one in the paper. But I guess it’s partly what spurred my interest in the topic, because I’ve come across a lot of hyperbolic statements about the superiority of perennial crops in the worlds of permaculture and alternative farming – including this article by Angelo Eliades and my subsequent tortuous debate with him, which prompted me to look into the issues in more depth. This kind of hyperbolic thinking can, in my view, be counterproductive. And as I argued in my previous post, the goal of a perennial grain export agriculture on the prairies and steppes to rival the existing annual one does not strike me as a good direction to aim in for an environmentally resilient and socially equitable agriculture.

In earlier posts, I’ve distinguished between what I call the ‘weak perennial vision’ (WPV) – farm or garden designs which combine perennial and annual plants with other landscape design features to create an overall system capable of producing food and other useful plant products with a minimum of environmental degradation – and the ‘strong perennial vision’ (SPV). The SPV holds that perennial plants can be as productive as annuals without any of the negative environmental consequences of cultivating the latter, and finds little or no place for annuals in its vision for a sustainable future agriculture. The SPV is a strong current in permaculture, which is why permaculturists are often dismissive of annuals (and a bit sheepish about the many annual plants that they do grow). I think the SPV incentivises permaculturists to talk up the productivity of their forest gardens, fruit forests and other perennial designs, and the Land Institute’s work sometimes figures in these efforts. There are many good reasons to plant orchards, forest gardens and suchlike, but input/output ratios to match annual staple crops are not, in my opinion, among them. Indeed, I notice something of a move away from the SPV towards the WPV in the permaculture world – as evidenced by the approach of prominent permaculturists like the late Patrick Whitefield and Toby Hemeway.

I’d like to think of my article as part of this trend to extol the virtues of the WPV and to recuperate annuals from the forbidding proscriptions of the founders. Of course, there are genuine reasons to fear the consequences of large-scale annual arable agriculture, as discussed in my previous post. But, as I’ve also previously discussed, there are genuine ecological and biogeographical reasons why agriculture has gone down this route which cannot easily be gainsaid by assertions as to the productivity of perennial crops currently. Maybe – maybe – at some point in the future the Land Institute or others will develop perennial staple agricultures that will render those comments obsolete, but in the meantime – to adopt a metaphor from annual cultivation – let’s call a spade a spade.

So that in a nutshell is my outline answer to C&D’s characterisation of my position and their criticism that I provide no evidence for it. It’s true that I don’t, but I think this reflects the fact that they and I have different reference groups. Theirs is a world of published scientific papers, mine of snatched conversations in permaculture gardens and smallholdings which defy attempts at quantification. With hindsight I should probably have further clarified this perspectival difference in the paper. But the evidence of distorted over-estimations of perennial productivity in the world of permaculture and alternative agriculture is there for those who care to find it – Eliades and Shepard who I’ve already referenced in these blog posts are cases in point. On numerous occasions I’ve heard people say that perennial crops are as productive or more productive than annuals. The evidence for this tends to vanish as you approach it, but quite often I hear the Land Institute namechecked as the authoritative source for these contentions.

Few people in the alternative farming world have the resources or training to produce credible scientific work of their own, so whether they know it or not, as paid up members of the scientific tribe the Land Institute folks carry quite a burden of responsibility for the thinking of grassroots alternative farmers and permaculturists. And I do think they’re partly to blame for the tendency to over-egg the perennial pudding in that world. Typically, their work is scrupulous, honest and modest. David Van Tassel states that breeding successful perennial grains may prove impossible, and that there will be difficult tradeoffs to overcome3. C&D talk about a managed agroecosystem, which they ‘hope’ can be maintained through endogenous nutrient supplies. This is what I’d call the Land Institute in its Dr Jekyll mode. But then up pops Mr Hyde with promises to “End 10,000 years of conflict between humanity and nature”4. Such claims are not, I’d submit, scrupulous or modest, but they do the rounds of the permaculture world. And to my mind, despite C&D’s doubtless well-founded comment that academic researchers developing both SPVs and WPVs complement and support each other’s work, I think their paper and the SPV literature in general still bears the traces of a somewhat lofty disdain for the fallen, compromised but practical and productive world of agricultural designs incorporating annuals.

In the grand scheme of things, there’s much going on in agriculture far more worthy of critical activism than the work of the Land Institute. It’s probably not that useful to divide people up into good guys and bad guys, but if it is then in my book Land Institute folks like Crews and DeHaan are on the side of the angels and I’ll happily concede their work is worth pursuing, even if I doubt it’ll achieve the successes they project. So I don’t really want to argue with the Land Institute, at least not when Dr Jekyll is at the helm. I’d like to debate with him certainly, but not argue. Mr Hyde is another matter.

Conclusion

To recap the arguments I’ve been pursuing over these last few posts, C&D characterise my analysis as follows:

  1. Ecological theory suggests that perennial grains may yield less than annual grains
  2. Strong criticisms of annual agriculture are unfounded, both socially and ecologically
  3. Focus on perennial grains detracts from more important strategies for achieving agricultural sustainability

Of these, (2) is a mischaracterisation, and (3) is not that important but if it is it’s mostly a plea on my part not to make over-inflated claims for an unproven project, and to consider the wider implications of a perennial grain export agriculture on the steppes. The crucial issue is (1). My analysis in this respect could be wrong, but C&D haven’t convinced me with their arguments, which ignore or understate the significance of the ecological and evolutionary factors conditioning the life histories of crop plants. To my mind, the Land Institute has not established the biological basis of its programme with sufficient rigour to justify its talk of ending 10,000 years of conflict between agriculture and nature.

I think we need people to be working on innovative solutions to our agricultural problems on many different fronts, so I’m really happy that the Dr Jekylls at the Land Institute are beavering away on perennial grain crops. But as for Mr Hyde, I think they should fire him from their programme. There’s an overconfidence in genetic manipulation and an underappreciation of ecological constraint in C&D’s position. And there’s too much Mr Hyde in their response to my article: instead of providing a measured overview of my analysis in the round, they pounce on its presumed weaknesses, try to condemn it out of hand by arguing for the inapplicability of Grime’s CSR framework to their programme, and ignore the things I’ve written that don’t fit with that vision. In particular, I think they underestimate the ecological and evolutionary stumbling blocks to their programme. To me, C&D’s paper reads like the defensive response of people who are too invested in the irreproachable rightness of their position. Ah well, I guess we’re all prone to that. Just as well there’s a big blank space below this post for folks to tell me why I’m wrong.

And that brings to a conclusion this cycle of blog posts about my strong perennial vision article. If you’ve read all of them: well, thank you very much – you rock. I’m now going to take a break for a couple of weeks to hmmm do some actual farming. And then I’ll be back with more gems hewn from the stony face of agrarian knowledge.

References

1. Smaje, C. 2015. ‘The strong perennial vision: a critical review’ Agriculture and Sustainable Food Systems, 39: 471-99.

2. Crews, T. and DeHaan, L. 2015. ‘The strong perennial vision: a response’ Agriculture and Sustainable Food Systems, 39: 500-515.

3. Van Tassel, D. 2012. Tradeoff or payoff? http://perennialgrainresearch.blogspot.co.uk/2012/11/biomass-accumulation-by-miscanthus-in.html

4. Cox, S. 2008. Perennial crop systems – future of food. Focus On Perennials 6: 14.

Of perennials, cereals and civilisations

This post continues with my exploration of Tim Crews and Lee DeHaan’s (C&D’s)1 counter-critique of my article ‘The strong perennial vision’2. One of C&D’s characterisations of my argument is that “Strong criticisms of annual agriculture are unfounded, both socially and ecologically” and that “the real challenge facing humanity is the social problem of how to adapt something like the European model [of agriculture] to other parts of the world”. That’s what I’m going to look at here, before wrapping things up next time with my final post on this issue.

Actually, this one is the easiest of C&D’s various characterisations of my argument for me to address because it’s not what I say in my paper and it’s not what I think. In fact, I think the criticism can be turned around – as I hope to show below it seems to me to be C&D’s project rather than my own which is more intent on adapting the European model of agriculture to other parts of the world.

Anyway, in my paper I cite approvingly Wendell Berry’s comment that we have not yet succeeded in developing sustainable, land-based, locally-adapted economies through the past history of cultivating (primarily annual) staple crops3. C&D cite various other interesting studies that further underline this point. I’m with them on this.

Nevertheless, I do think that there are some places where annual agriculture is relatively less damaging, and C&D confirm that Northwest Europe (where I live) is one of them. Given the profound transformations required if we’re to move to a sustainable agricultural economy worldwide, I’d argue that practising thoughtful annual agriculture in places where it’s ecologically feasible, and working towards methods that minimise its negative impacts are worthwhile things to be getting on with, at least for the time being. Sometimes the best can be the enemy of the good. Permaculture emphasises local, specific solutions, so it beats me why so many permaculturists seem to think that something which may be a good idea in Kansas is necessarily a good idea in Kent.

But I’d further argue that even replacing annual grain agricultures with perennial grain agricultures may not be enough in the end. Historian Geoff Cunfer has suggested that the Dust Bowl in the US prairie states of the 1930s was a natural calamity caused by drought and wind that afflicted areas under native perennial groundcover as well as under annual cereal cultivation4. If he’s right, then perhaps this points to the conclusion that the prairies are an inherently fragile environment for human ecology which will be prone to periodic disturbance regardless of whether those farming them grow annual or perennial crops.

Prior to European colonisation the prairies were sparsely populated by horticultural peoples in the wet and wooded valleys, and then later with the availability of horses by the bison-hunting plains cultures. With the arrival of farmers at the expanding frontier of European colonisation the bison were slaughtered, the Indians mostly killed or exiled, and the prairies ultimately turned to a productive but ecologically precarious export-oriented annual grain agriculture which – along with the agricultures of other semi-arid continental grassland regions of the world – created a global grain market highly undermining of many more localised agricultures worldwide, and supportive of anti-peasant urbanisation. There’s a statistically significant correlation at the country level between (prairie/steppe) grain import dependence and urbanisation. But it may turn out that however people farm them, the agricultural days of the prairies are numbered, especially with factors like the depletion of the Ogallala aquifer to consider. That may be no bad thing in the long run.

Cunfer argues that humans are not the masters of the ecologies into which they’re inserted, but are forced to react to circumstances beyond their control, particularly the vagaries of climate. I think he’s too sanguine about the human ability to adapt adequately to such circumstances, but his Leopoldian point about our lack of mastery of the ecosystems we inhabit seems right. At least it strikes a more convincing tone to me than the Land Institute’s programme of genetic manipulation of perennial plants, apparently unconstrained by any extant prairie ecologies, with the putative aim of replicating annual grain yields.

This aim seems implicitly supportive of the USA’s existing grain export agriculture (the US is responsible for around 20% of global wheat exports and 40% of global maize exports, most of which are grown in and around the prairie states). I would argue that these exports are destructive of more sustainable and locally-adapted agricultures elsewhere in the world – a thesis I pursue at greater length in an article I hope will soon be published in The Land Magazine5. Why should anyone concerned with sustainable agriculture be aspiring to shore up the long-term future of such an agriculture by aiming to match its surpluses? Here, I think there are some tensions in the Land Institute’s project between the writings of its founder Wes Jackson on a sustainable, locally-appropriate agriculture – on becoming ‘native to one’s place’ to use one of Jackson’s essay titles6 – and C&D’s apparent conviction that it’s possible and desirable to develop a perennial grain agriculture to rival the existing annual one.

For their part, C&D don’t seem to hold any type of annual cultivation in high regard. At the plot level, they cite evidence for the superiority of their perennial kernza grain crop in preventing nitrate leaching over conventional or organic annual wheat. At the collective level, they cite evidence for the soil-destroying activities of various ancient civilisations in Europe, Meso-America, Southwest Asia and East Asia which, they argue, “experienced rather spectacular levels of soil degradation and erosion, in spite of the fact that they were small-scale, diversified, labor intensive, locally adapted farming systems”.

This is all interesting stuff. It sounds a bit reminiscent of Mark Shepard’s jeremiads about the collapse of annual tillage civilizations that I criticised in a recent post, though less extreme. I don’t mean to minimise the genuine issue of soil destruction by annual tillage agriculture. Perhaps I should have emphasised this more strongly in my paper. Perhaps C&D would now reject the view espoused in an earlier Land Institute paper co-authored by DeHaan that “In sparsely distributed garden-sized patches, annual grains would have limited negative impact”7. But I’m not sure they should. At the plot or farm level, nitrate leaching is obviously best avoided, but if one were to take a permaculture (whole systems) approach, perhaps it could also be addressed by methods such as on-farm water management, contour cropping, mixed cropping, silvo-arable designs and so on. On the face of it, it doesn’t seem obvious to me that breeding perennial grain crops is the only or necessarily the most promising solution to the problem.

On the matter of the soil degradation wreaked by past civilisations, this is something I will address more fully in the future, but I would argue that these civilisations were not sustained by what anyone really ought to call ‘small-scale, diversified and locally adapted farming systems’. They may have been small-scale by today’s standards, but these civilisations were surely the pioneers of the large-scale, export-oriented annual cereal monocropping that underlies many of our contemporary agricultural troubles. And inasmuch as these civilisations were dependent upon small-scale peasant cultivators, the rents in grain they extracted to fund their opulence typically forced peasant cultivators into unsustainable and overdriven agricultural practices. These practices are not intrinsic to small-scale annual cultivation as such.

Philip Grime describes humans as intermediate SC strategists (see here for an explanation of Grime’s work and its relevance to my analysis). In my paper I briefly explore the implications of his framework for human history (albeit that here I confess I am using his framework in a very general sense): from the typical S or SC strategies of hunter-gatherers and swidden farmers, to the C strategy of commercial annual arable farming and onwards, within the constraints of our primate biology, to the R strategy of the great agricultural civilisations, including our own, which produce vast multitudes of impoverished people who struggle to get enough to eat and are treated as essentially expendable by political elites. It hardly seems feasible nowadays to return to S strategy hunting and gathering, but I think there may be scope for retreat towards SC local horticultural strategies. Zohary et al suggest that this is what has happened in the past8. I think it’s worth considering again. To do so would require a primary focus on social reform of societies, not genetic reform of plants.

In summary, I most certainly don’t think that people should apply European-style farming approaches everywhere. Nor do I think they should apply American prairie-style farming approaches everywhere, as all too many permaculturists seem poised to do through their baffling enthusiasm for perennial grains. Instead, I think people should be able to develop whatever agricultural solutions seem promising long-term bets in their locales (and in this respect, the less grains that get traded around the world from the semi-arid continental grasslands to undermine local agricultural adaptations, the better for everyone).

Generally, a good clue to sound long-term agricultural solutions can be found in the mixed farming systems which preceded the recent rise of export-oriented mechanised farming. On that basis, I think Western European agriculture might feasibly include annual grains, though probably not in the fashion of the increasingly prairie-like landscape of large-scale annual arable farming in contemporary Europe. Perhaps we’d do well to move away from grains altogether as much as possible and towards more vegetables (more horticulture) on nutritional as well as environmental grounds. For Kansas, well, I don’t know – long term, I think maybe you guys are screwed, and not even perennial grains will save your ass. Long term, I think farming of any kind may prove to be a failed experiment to push human numbers beyond feasible carrying capacity across large parts of the globe.

But if I were living in Kansas today and thinking about these things, I’d probably go with my own local history of mixed agriculture, offer a prayer to slaughtered Indians and bison, and be thinking buffalo commons and horticulture down in the wet river valleys. And yes, why not some kernza? I doubt it’ll yield as much as wheat or corn, but that’s a blessing in disguise if it helps put a stop to global grain export agriculture. Consider the following calculations I’ve undertaken with the help of a nearby envelope and that unimpeachable oracle, Wikipedia:

The population of Kansas is 2.9 million, which equates to an annual calorific requirement of something like 2.65 million million calories. There are 46 million acres of farmland in Kansas. Suppose 70% were turned over to native perennial forage for bison, 20% to intermediate wheatgrass to produce grains for human consumption, and 10% for vegetables and other crops for micronutrients and other needs producing, for the sake of argument, no useful food energy. I figure on producing 10kg of bison meat per acre annually, and about 250,000 nutritional calories per acre of intermediate wheatgrass (far less than current yields of annual wheat). By my calculations, together the meat and the wheatgrass (mostly the wheatgrass) would more than meet Kansans’ calorific requirements. Job done already.

I imagine that the residents of, say, New York City might have something to say about this new departure in Kansan agriculture, but I’m sure it would do wonders for concentrating their minds on what’s really important in life, as well as providing a welcome shot in the arm for city lot agriculture. Alternatively, if all US farmland was given over to a wheatgrass ‘domestic prairie’ my estimate is that it could provide enough gruel to satisfy around 90% of its citizens’ calorific needs. OK, so the US would then have to become a net food importer for a change, but I’m sure that would do wonders for concentrating…etc etc. Job almost done already. As a perceptive Kansan farmer of the 19th century who I have already quoted on this blog would put it, “Let us not spend nature’s accumulated fortune on riotous farming”. Perhaps that goes for riotous perennial grain farming too.

I admit that a slightly more sophisticated analysis of global food futures is required than the one I’ve provided in the preceding paragraph. But I stand by my basic contention: more than genetic reform of our crop systems what humanity really needs is social reform of our food systems, and our social systems. But then I’m a social scientist. I guess I have my own biases.

References

1. Crews, T. and DeHaan, L. 2015. ‘The strong perennial vision: a response’ Agriculture and Sustainable Food Systems, 39: 500-515.

2. Smaje, C. 2015. ‘The strong perennial vision: a critical review’ Agriculture and Sustainable Food Systems, 39: 471-99.

3. Berry, W. 2002 The whole horse: the preservation of the agrarian mind. In A. Kimbrell  (ed.) The Fatal Harvest Reader. Island Press.

4. Cunfer, G. 2004. On The Great Plains. Texas A&M University Press.

5. Smaje, C. ‘The dearth of grass: colonialism, cereals and civilisations’ Unpublished MS.

6. In Jackson, W. 2011. Nature As Measure, Counterpoint.

7. DeHaan, L. et al. 2007. Perennial grains. In S. Scherr  and J. McNeely (eds.). Farming With Nature: The Science And Practice Of Eco-Agriculture. Island Press.

8. Zohary, D., Hopf, M., and Weiss, E. 2012. Domestication of Plants in the Old World. Oxford University Press.

The strong perennial vision: a response

Timothy Crews and Lee DeHaan (henceforth, C&D) of the Land Institute have written the above-titled paper1 in response to my paper ‘The strong perennial vision: a critical review’2, which I’ve discussed in my previous two blog posts. As mentioned in those posts, C&D provide this threefold characterisation of my argument:

  1. Ecological theory suggests that perennial grains may yield less than annual grains
  2. Strong criticisms of annual agriculture are unfounded, both socially and ecologically
  3. Focus on perennial grains detracts from more important strategies for achieving agricultural sustainability

The first of these points is much the most important, and that’s what I’m going to focus on in this post.

C&D versus CSR

C&D’s main gambit is to suggest that Grime’s CSR theory (described in my previous post) is a general framework for understanding plants in their habitats, which becomes misleading when it’s applied in the manner I use it to specific plants, particularly plants under artificial selection. There’s some force to the first part of this objection. There’s continuous variability of plants across multiple traits, not complete segregation into C, S or R types. And, certainly, there is no cast iron law of ecological logic that demands augmentation of one trait must inevitably lead to the diminishment of another. So possibly it’s true that I use the CSR framework in too general a way, and that I interpret tradeoffs too stringently.

But though the CSR framework is indeed a generalising one, Grime himself and me in my usage of his framework do focus on two specifics: resource availability and disturbance. By contrast, C&D in their discussion of ‘stress tolerance’ invoke it in a very much more general sense to mean anything that stresses the plant. Then they go on to have some fun at my expense by using the framework very specifically in order to identify various complexities of stress tolerant, ruderal and competitive traits that transcend the annual-perennial divide, and of the existence of high resource (but non-seedy) herbaceous perennial systems.

In my view, it’s best not to fixate on ‘perenniality’ as such but instead to examine the covariance of traits like longevity, sexual allocation etc. So I’m not sure how much of C&D’s discussion here is relevant to my arguments, and I’m not sure how much they and other Land Institute authors really understand the relationship between resource availability, disturbance and sexual allocation. But yes I concede that there’s plasticity of plant traits with which plant breeders can work. How much? In C&D’s opinion, a lot: whereas I posit a tradeoff between augmenting stress-tolerant traits (low resource input, individual survival) and sexual allocation, they profess “no experimental evidence [of this] to our knowledge”.

So in C&D’s view, the CSR framework goes out the window and plant breeders have a free hand to work with the unique traits of given plant species which, through artificial selection, they can work up into whatever phenotypes they want. CSR theory, in this view, “does not address what happens if humans were to create a new type of habitat never before seen in nature”. The kind of habitat they have in mind, their ‘domestic prairie’ of perennial grains, is one that “requires the development of a never seen in nature environment with high resource availability, little tillage, and with strict human directed selection for maximum seed yield over several years”. C&D criticise me for misconstruing domestic prairie as something requiring little or no human inputs or management, and for being too hidebound in my thinking about feasible agroecosystems by the habitats that are actually found in nature. Instead, they invoke the authority of Professor Ford Denison who argues that “humans will likely have the greatest success in breeding for traits that were never previously selected for in nature”.

Of selection, natural and artificial

Let me try to work through some of this. First, it’s noteworthy to learn – despite all of Wes Jackson’s writings on ‘natural systems agriculture’ and the mimicking of natural ecosystems – that C&D’s programme turns out to depend on an absolute break with natural ecosystems more thorough than that of extant agricultures, and indeed unprecedented in the history of agriculture to date. That doesn’t necessarily mean it’s a bad idea or that it won’t work, but I think those permaculturists who enthuse about perennial grain crops as an example of nature mimicry might sit up and take note. Still, with Denison’s work as inspiration, C&D pursue a line of argument that’s certainly plausible: unaided by human hand, natural selection won’t necessarily find solutions that work well in agriculture for human purposes.

But let me pursue an alternative, more permaculture-oriented and nature-mimetic argument than C&D, with Denison once again acting as my guide. Perhaps natural selection hasn’t come up with seedy herbaceous perennials because such plants involve fundamental tradeoffs or contradictions which artificial selection will be unable to surmount any better than natural selection. Denison certainly thinks so – his book Darwinian Agriculture3 has a chapter called “What won’t work: misguided mimicry of natural ecosystems”. Its premier example is the Land Institute’s perennial grain breeding programme.

So it seems to me a little cheeky for C&A to invoke Denison in support of their programme. It’s true that Denison argues for the merits of breeding for traits not previously selected for in nature, but the sort of examples he uses (like short-strawed cereal varieties) are more consistent with my emphasis on pushing plants in directions they’re already predisposed to go in evolutionarily than in a contradictory push to increase both sexual allocation and individual survival.

If it’s true that through careful selection of plant traits crop breeders can overcome the basic biological tradeoffs encountered by wild plants, then C&D may be right that Grime’s framework is irrelevant here, that there are no fundamental obstacles to producing high-yielding, endogenous nutrient-cycling perennial grain crops, and that these plants will not be subject to existing ecological constraints. But I don’t think it is true. I take the point that there’s underlying plasticity and complexity of traits amongst plants that isn’t captured in a simple framework like CSR. In ecology these days, life history seems to trump r/K or CSR. Citing Barbour et al4, C&D state “There are as many life history patterns as there are species…” Perhaps. There is always a scientific tradeoff between generalisation and particularisation. C&D try to have it both ways by invoking CSR theory in a very general way to refute the specifics of my analysis and in a very specific way to refute the generalities of my analysis. But to infer that there is no higher level ecological patterning of life history involves the mistake of not seeing the wood for the trees in an almost literal sense.

In his early work Grime adduced the CSR framework in relation to detailed studies of English grassland plants. In his more recent work, he’s applied it to the whole of the biota throughout the history of life on earth – whence his statement that the outcomes of natural selection are restricted “to a rather narrow range of basic alternatives in life-history, resource allocation and physiology”5. These are what Grime calls the ‘evolutionary strategies that shape ecosystems’, which are applicable to past, present and, one must assume, future ecosystems.

I’m not sure on what grounds C&D think the plants they breed can escape these evolutionary constraints simply by virtue of the fact that they have been artificially selected. That’s not the case with the current suite of artificially selected annual crop plants, which bear all the traces of those constraints ordained by natural selection – hence the whole problem of annual tillage agriculture. To me, C&D’s position greatly overstates the autonomy from Grime’s ‘narrow range of basic alternatives’ that can be achieved by artificial plant breeding. Sure, we can push the envelope with things like fertiliser and pesticide laced short-lived orchard trees propped up on sticks on dwarfing rootstocks. In their paper, C&D make quite a play against my view that the example of high input/output apple orchards isn’t a sensible prototype for a sustainable perennial agriculture and involves a hypostatisation of perenniality per se. But to my mind, the example of the intensive orchard exemplifies precisely the tradeoff problems associated with issues like survival, longevity, nutrient response and agroecosystem management that I explore in my paper in detail and that C&D ignore almost entirely in their response.

C&D say that there’s no experimental evidence for the tradeoff I posit between sexual allocation and perennial-type survival traits. Grime’s framework provides an experimentally-validated evolutionary and ecological context, while Peggy Wagoner’s 1990 review6, supplemented by various more recent studies I cite, is a veritable litany of artificially-bred perennial grain varieties that either survived well and produced little seed, or produced a lot of seed and survived poorly. In a blog post7, Land Institute breeder David Van Tassel explicitly acknowledges that perennial grains will be subject to various tradeoffs, and in my paper I explore the biological basis of these in detail – an analysis again ignored by C&D in their response.

The most compelling evidence C&D invoke to refute my suggestion of a sexual allocation–survival or longevity tradeoff is a study of sunflowers in which ‘early successional perennials’ had a higher sexual allocation than annuals. Well, nature is never quite as orderly as our models of it, but I can’t say I find a slight anomaly of this sort across longevity or R-C-S trends hugely undermining of my basic argument, and as I’ve already said CSR may be a better way of thinking about the issues than annual vs perennial. I’d like to know how long-lived the high-allocating early successional sunflowers were, their survival rate, whether they exceeded annual allocations in every year of their lives, and whether the studies controlled for allometry. Unfortunately, I’m unable to access the relevant paper, but its abstract states “A number of studies have tested whether reproductive effort (RE) is correlated with successional maturity; in these, annuals generally had higher RE than herbaceous perennials (29 and 13%) and RE in herbs often diminished as succession progressed”8. On the face of it, this looks to me more confirmatory of my arguments than of C&D’s.

Probably the best experimental evidence for the difficulty of breeding perennial grains that can match the yields of annuals is the fact that nobody has managed to do it in at least 10,000 years of extraordinary agricultural achievement, and in over 100 years of professional, scientific plant breeding. Land Institute authors have written a paper that explains with some degree of plausibility why the first farmers were unlikely to have domesticated perennial grain crops9, but if the problem is mostly just a matter of coming up with the right set of traits to work with, the historic, global failure to have found them anywhere in the world at any time since seems to me quite a troubling issue for their line of argument. More plausible, I think, to accept Peggy Wagoner’s view: “the resources available for seed production in a perennial appear to be less than in an annual”6.

Domestic Prairie

C&D describe the ‘domestic prairie’ that the Land Institute is working to develop as a “never seen in nature environment with high resource availability, little tillage, and with strict human directed selection for maximum seed yield over several years”, and they think I misconstrue the concept as something more natural and less interventionist.

Perhaps I am muddled about domestic prairie. I do find it a rather elusive concept. According to Wes Jackson it’s “based on nature’s ecosystems” and has something to do with “natural systems”10; according to C&D it’s that never-seen-in-nature environment and a high resource input agroecosystem where they “hope that as much as possible these resources can come from nutrient cycling and endogenous sources”; and according to Jackson and other Land Institute authors it’s something that’s going to end 10,000 years of conflict between agriculture and nature. Most annual grain farmers surely hope that “as much as possible” their nutrient inputs can come from endogenous sources too. How much is C&D’s “as much as possible” and what yields will be associated with it? The answer to that question is surely critical, but C&D don’t address it; instead, they studiously ignore my paper’s analysis of nutrient response, and invoke the misleading example of non-starchy and non-seedy forage and perennial biofuel crops.

At what point does ‘domestic prairie’ segue into ‘green desert’? When does ‘natural systems agriculture’ become plain old anthropogenesis? Would a polyculture of Roundup Ready® alfalfa and corn be domestic prairie? And how exactly is all of this going to end the conflict between agriculture and nature? In a recent post I criticised Mark Shepherd’s emphasis on nature mimicry in his ‘restoration agriculture’ project for its protean character, and I think the same is true of C&A’s domestic prairie. Basically these systems (probably all systems) mimic nature except where they don’t, and the concept of ‘nature mimicry’ then becomes essentially rhetorical.

The discussions around both perennial grain domestic prairie and Roundup Ready® domestic prairie seem to me to overstate the extent to which agricultural problems are reducible to plant breeding problems. In both cases, it’s as if agricultural problems can be solved purely or largely by genetic manipulation of plant traits without any messy ecology getting in the way out in the field. In the case of Roundup Ready® corn, that conceit is already belied by the emergence of Roundup tolerant weeds. With perennial grains, I think there will be different but no less daunting problems. These essentially revolve around the very narrow parameters involved in juggling high sexual allocation in a protein or carbohydrate rich seed crop with high perennation year after year, funded only out of longer-season photosynthesis, through the vicissitudes of weather and climate to produce agriculturally acceptable outputs within the ebb and flow of complex plant guilds, with no or at least ‘little’ (the distinction is probably quite significant) herbicides, pesticides, fertilisers or tillage despite their high resource demands. Before anyone starts talking about ending 10,000 years of conflict between agriculture and nature, I’d like to see some sound numbers put to those parameters.

Conclusion

I accept that there’s plasticity with which plant breeders can work, and if somebody could explain to me what domestic prairie really is I could probably be persuaded that it’s possible to develop a domestic prairie of decently yielding and decently long-lived perennial grains, though probably not as high yielding as annuals. In fact, I already accepted this possibility in my paper. But I’m not convinced that C&D and the Land Institute adequately emphasise the extremely tight parameters within which such a domestic prairie would have to operate and the tradeoffs it would have to reconcile if it’s to found a high-yielding low environmental impact grain agriculture long-term. And, as I’ll explain in my next post, I’m not sure a high yielding grain agriculture is such a great idea in any case.

References

1. Crews, T. and DeHaan, L. 2015. ‘The strong perennial vision: a response’ Agriculture and Sustainable Food Systems, 39: 500-515.

2. Smaje, C. 2015. ‘The strong perennial vision: a critical review’ Agriculture and Sustainable Food Systems, 39: 471-99.

3. Denison, F. Darwinian Agriculture, Princeton University Press.

4. Barbour, M. et al. 1987. Terrestrial Plant Ecology. Benjamin/Cummins.

5. Grime, J. and Pierce, S. 2012. The Evolutionary Strategies That Shape Ecosystems. Wiley-Blackwell.

6. Wagoner, P. 1990. Perennial grain development – past efforts and potential for the future. Critical Reviews in Plant Sciences 9: 381-408.

7. Van Tassel, D. 2012. Tradeoff or payoff? http://perennialgrainresearch.blogspot.co.uk/2012/11/biomass-accumulation-by-miscanthus-in.html

8. Hancock, J. and Pritts, M. 1987. Does reproductive effort vary across different life forms and seral environments? Bulletin of the Torrey Botanical Club 114, 1: 53-59.

9. Van Tassel, D., DeHaan, L., and Cox, T. 2010. Missing domesticated plant forms: can artificial selection fill the gap? Evolutionary Applications 3: 434-52.

10. Jackson, W. 2002. Natural systems agriculture: a truly radical alternative. Agriculture, Ecosystems and Environment. 88: 111-117

The strong perennial vision: critical review and critical response

Following on from my previous post, this is a brief introduction to my paper ‘The strong perennial vision: a critical review’1 in the journal Agroecology and Sustainable Food Systems and the response2 it evoked from the perennial grain breeders at the Land Institute.

The paper distinguishes between what I call the ‘weak’ and ‘strong’ perennial visions. The former involves combining the benefits of annual crops (fast growth, high allocation to seeds and other edible structures) with perennial crops (low input/low output, land conservation) and with other features of landscape design to optimise the goals of a productive and resilient/sustainable agriculture. The latter also considers perennial crops to be low input and land conserving but disputes the idea that they are necessarily low output – therefore it finds little or no place for annual plants in its vision of sustainable agriculture.

This strong perennial vision (SPV) is pervasive in the permaculture movement:see, for example, this post by Angelo Eliades, or this book by Mark Shepard, which I’ve discussed here and here. But its exponents with the greatest scholarly credibility are the perennial grain breeders at the Land Institute, who are attempting to overcome the environmental damage caused by the cultivation of annual cereals on the fragile steppe ecology of the US prairies by developing perennial grain crops which produce a high edible yield without the need for (much) tillage, fertilisation and pest control. Following the lead of their founder Wes Jackson3, Land Institute authors have argued that perennial crops can be just as productive of seeds as annuals4, and that developing such varieties will end 10,000 years of conflict between humanity and nature through annual agriculture5.

On the face of it, proponents of the SPV seem to have nature on their side – most wild floras are perennial, and wild plant ecosystems get by just fine without any tillage, fertiliser application etc. The puzzle then is why, if perennials involve less work for equal return with added environmental benefits, most human agricultures rely on annual crops, at least for their staple foods. Surely farmers through the ages weren’t so stupid as to engage in endless, environmentally-damaging labour for no added benefit?

Angelo Eliades thinks they were, arguing that the choice of annuals over perennials arose through ‘ignorance and lack of perspective’. I found that implausible, and it struck me that there’s likely to be some kind of ecological and/or biogeographical explanation for the annual preference in human agriculture. A more promising line of enquiry is opened up by Steve Gliessman in his book Agroecology6 in which he characterises perennials as essentially K-selected (slow and cautious reproducers – in mammalian terms, think whales), whereas annuals are r-selected (fast and prodigious reproducers – think rats). The plant ecologist Philip Grime7 builds on this r/K distinction in his ‘CSR’ theory, which identifies three plant strategies associated with habitat resource availability and disturbance: in resource-rich, disturbed habitats you get short-lived, fast-reproducing plants (‘ruderals’) which quickly produce a lot of seed in order to found the next cycle of growth. In resource-rich, undisturbed habitats you get somewhat longer-lived, often vegetatively reproducing plants (‘competitors’ – typically short-lived perennials). And in resource-poor, undisturbed habitats you get long-lived, slow-turnover plants more adapted to their own long-term survival than to short-term reproduction (‘stress-tolerators’ – typically longer-lived perennials).

To my mind, the CSR framework provided an immediate outline answer to the annual crop domestication puzzle. The key staple crops are ruderals or ruderal-competitors, and the key farming operations involve reproducing the conditions propitious for ruderal growth – disturbance (tillage), and resource augmentation (fertilising, weeding). Another side to it is the fact that the majority of crop assemblages in global agriculture accord pride of place to cereals. These are typified by large, starchy seeds which are essentially an adaptation to aridity and seasonal variation in precipitation. Only in the aseasonal humid tropics do we tend to find perennial staple crops, such as bananas. So the reasons our agrarian ancestors domesticated annuals and global agriculture continues to be so reliant on them are ecological and biogeographical, not because of human stupidity or because our ancestors made an ‘honest mistake’ (in Land Institute author Thomas Cox’s words8) by backing the wrong botanical horse.

That in a nutshell, or at least in a grass seed, is my argument as to why our agricultures as opposed to our wild floras are so dominated by annuals. Looking at agriculture through the lens of Grime’s CSR theory, it seems fairly obvious why it took the annual tillage/fertilisation course in seasonal climates that it did, and it surprises me that this explanation isn’t more widely noted. Some time ago I wrote to Professor Grime asking him if he thought my interpretation sensible, and in a brief response he answered affirmatively. This encouraged me to pursue my analysis which, following Grime, emphasises the importance of ecological constraint: there are various tradeoffs between reproductive allocation, longevity, growth, nutrient response, defence from herbivores and so on that are not easily soluble and which result in characteristic basic patterns in life-history, resource allocation and physiology9. I explore these in detail in my paper.

In the original version of the paper I took a wider look at perennials in global agriculture and submitted it to a different journal. It was rejected, partly on the recommendation of a reviewer who opined that nobody questions the role of annual crops in world agriculture, and also that plant breeders ‘yawn’ when people talk of difficult ecological tradeoffs in crop development, because overcoming tradeoffs is what plant breeders do all the time. So I decided to rewrite the paper with a narrower focus on those who manifestly do question the role of annual crops in world agriculture – ie. on the strong perennial vision, and on the work of the Land Institute in particular – to overcome the first objection. I also felt a certain irritation with the hubris of ‘yawning’ plant breeders, whose success in overcoming ecological constraint I consider far less impressive than is often supposed. The all-conquering power of the plant breeder to solve agricultural problems seems to be part of the present zeitgeist – whether through GMOs in mainstream agriculture, or through breeding perennial grain crops in ‘alternative’ agriculture. While I don’t dispute the vital role of plant breeding, I’m not convinced on either count.

That, in fact, is a key contention of the paper. Its meat (or starch, maybe?) is a series of subsections on historical crop domestication, sexual allocation, nutrient response, leaf economics, longevity and agroecosystem management which point up the many difficult tradeoffs that perennial grain breeding has to overcome if it’s to produce starchy perennial crops that come close to the present yields of annual cereals without the tillage, irrigation, fertilisation and pest control regimens which are so environmentally damaging in the latter case. I’m not saying that it’s entirely impossible for breeders to overcome these tradeoffs, but I do think it will be incredibly and unprecedentedly difficult. And it has not been conspicuously successful to date.

I also think that a hard distinction between annuals (bad) and perennials (good) is misleading. It seems likely that the agricultural solutions which will optimise productivity and environmental conservation will probably be competitor crops – perennials, yes, and relatively productive, but also relatively short-lived, and relatively demanding of nutrients. Will such crops produce tolerable yields and better environmental performance than our current suite of annuals? Probably. Will they produce as much as annuals but with fewer inputs, and will they end 10,000 years of conflict between agriculture and nature? Probably not.

If I turn out to be right, what are the implications for agriculture? I’ll look at this in more detail in an upcoming post, but I was struck by a comment from the perennial grain breeders at the Land Institute that “In sparsely distributed garden-sized patches, annual grains would have limited negative impact”4. As an advocate of small-scale, ‘garden-sized’ farming for many different reasons, that interested me, so in the latter part of my paper I developed this idea a little. To grow annual grains on a small scale as part of a diversified small farm economy would involve little new plant breeding work, but would involve huge sociological changes in human ecology – a point I briefly discuss in the paper. I also noticed that most of the perennial grain-breeding work to date has been done in semi-arid continental grassland biomes (eg. Kansas, where the Land Institute is based) which (1) arguably are at especially high risk of soil degradation through annual cultivation methods; (2) mostly developed annual grain agricultures relatively late historically as a result of colonial processes; and, (3) also happen to be the major grain exporting regions of the world. So I discussed this a little too.

So much for my paper. Let me now look very briefly the Land Institute’s response. They provide a threefold characterisation of my arguments as follows:

  1. Ecological theory suggests that perennial grains may yield less than annual grains
  2. Strong criticisms of annual agriculture are unfounded, both socially and ecologically
  3. Focus on perennial grains detracts from more important strategies for achieving agricultural sustainability

I’ll discuss these points in turn in my upcoming posts. In brief, the second one is basically a mischaracterisation of my argument, while the third issue is…complicated. Much the most important point of contention is the first. In essence, the Land Institute suggest that I interpret the tradeoffs implicit in the CSR framework too stringently and apply the model in too over-general a way to the issue of crop development. Whereas I argue that to produce high yielding perennial crops would involve trying to optimise in opposite ruderal-stress tolerator directions, they dispute the evidence for this, giving various examples of annual crop development that involves breeding in more S-type characteristics, and of perennial plants (including fruit and ‘early successional perennials’) with high reproductive allocation. They go on to say that CSR theory doesn’t address what happens if humans were to create a new type of habitat never before seen in nature, which is what they’re attempting to do in creating what they call a ‘domestic prairie’, that is, an untilled polyculture of edible perennial crops. Here, they suggest I misunderstand the phrase ‘domestic prairie’ as something requiring no human intervention other than harvest: their vision of domestic prairie on the contrary involves management for high resource availability. And they claim I err in thinking that because high-yielding perennial grain crops haven’t previously been found in nature, they’ll be difficult for future plant breeders to develop.

With the other two characterisations of my argument, the Land Institute take issue with me by citing evidence that “small-scale, diversified, labor intensive, locally adapted farming systems” such as those that served the civilisations of the Fertile Crescent, China, Rome and Mexico experienced “spectacular levels of soil degradation”. They also cite recent evidence from Michigan that plots growing perennial intermediate wheatgrass leach far less nitrates under synthetic or organic management than comparable plots of annual wheat. And quoting my comment that “the emphasis on perennial grains as a solution to the manifest problems of annual cereal cultivation paradoxically risks diverting attention from the importance of pursuing more diverse agroecological strategies” they state that I offer “no data on trends in funding, literature published or cited to support this concern. Nor [do I] substantiate the perception that groups working on what [I call] the strong and weak perennial visions are competing for attention or resources”.

That, I hope, provides a basic overview of the arguments and counter-arguments. In my upcoming posts, I’ll move on to some evaluations.

 

References

1. Smaje, C. 2015. ‘The strong perennial vision: a critical review’ Agriculture and Sustainable Food Systems, 39: 471-99.

2. Crews, T. and DeHaan, L. 2015. ‘The strong perennial vision: a response’ Agriculture and Sustainable Food Systems, 39: 500-515.

3. Jackson, W. 1980. New Roots For Agriculture, University of Nebraska Press; Jackson, W. 2011. Nature As Measure, Counterpoint.

4. DeHaan, L. et al. 2007. Perennial grains. In S. Scherr  and J. McNeely (eds.). Farming With Nature: The Science And Practice Of Eco-Agriculture. Island Press.

5. Jackson, W. 2002. Natural systems agriculture: a truly radical alternative. Agriculture, Ecosystems and Environment. 88: 111-117; Cox, S. 2008. ‘Ending 10,000 years of conflict between agriculture and nature’ http://www.i-sis.org.uk/Ending10000YearsOfConflict.php.

6. Gliessman, S. 2006. Agroecology, CRC Press.

7. Grime, JP. 2001. Plant Strategies, Vegetation Processes and Ecosystem Properties. John Wiley and Sons.

8. Cox, S. 2008. Perennial crop systems – future of food. Focus On Perennials 6: 14.

9. Grime, op cit; Grime, J., and Pierce, S. 2012. The Evolutionary Strategies That Shape Ecosystems. Wiley-Blackwell.

The strong perennial vision: Small Farm Future versus The Land Institute…

Continuing with my perennial and annual cropping theme, my scientific paper about perennial grain crops, ‘The strong perennial vision: a critical review’ has now been published online by the academic journal Agroecology & Sustainable Food Systems1 (A&SFS), and is currently freely downloadable from here. It’s accompanied by a response from the Land Institute2, whose work is, I suppose, the main target of my criticism in the paper. The Land Institute folks are not at all persuaded by my analysis. And I’m not at all persuaded by their response. But I’ll come to that in a minute.

The paper has emerged through my involvement in the permaculture/alternative farming scene over recent years, in the course of which I’ve heard it said countless times that perennial plants are more ecological, more nature mimetic, less labour-demanding, less resource-demanding and equally or more productive than annual plants, or at least potentially so. This is what I call the ‘strong perennial vision’ (Mark Shepard, whose book I’ve been considering in my previous two posts, is one of the vision’s more sensible proponents). In the light of this apparently overwhelming superiority of perennial plants, it becomes quite a puzzle as to why most farmers globally and throughout millennia of agricultural history have perversely favoured annual crops, and particularly annual staple crops.

So I decided to look into this. The paper I’ve published was the result, and it answers to my own broad if not quite complete satisfaction this puzzle – to wit, that (depending a little on exactly how you define ‘perennial’) perennial crops are not as productive as annual crops, and probably never will be, however much plant breeders strive to make them so. They’re probably productive enough to found a workable agriculture, and they’re certainly less ecologically damaging, by and large. But that’s not the issue. The issue is that, pace the strong perennial vision, perennial plants cannot match annual productivity and do not return higher resource outputs relative to resource inputs.

The implications of this finding are, I think, that we should either accept this limitation of perennial crops and build our agricultures around them accordingly, or we should find better ways to combine annual and perennial crops with other aspects of locally appropriate landscape design in order to optimise the various goals of agriculture: principally feeding everyone sufficiently and well, and conserving our ability to continue doing so into the future. Either way, I think as much or more emphasis must be placed on changing the social basis of agriculture than on changing its genetic basis through breeding new kinds of crops. That’s not to say that plant breeding isn’t a vitally important part of the picture. But I do think there’s an element of what I call ‘plant breeder hubris’, both among conventional/GM breeders and alternative breeders such as the Land Institute people, who judge their efforts to have transcended basic biological and ecological limitations far more thoroughly than I think is justifiable.

In any case, as a non-academic (OK, ex-academic), full-time farmer with no formal background in ecology or agronomy I’m pleased to have been able to put together a sufficiently plausible analysis of the issues to pass muster in a peer-reviewed agronomic journal. Maybe I should leave it at that, and focus my writing and practice from now on around those issues of social change in human ecology to which I referred. But I feel the need to engage with the Land Institute’s response to my paper. Partly it’s out of basic intellectual interest in the issues, and partly it’s because the debate with them spins off in various directions that I’m exploring in some forthcoming articles in the alternative farming press – so I want to provide further background resources and analysis here for issues raised in those articles that can’t be properly explored in them for want of space.

If I’m honest, though, I also want to respond because I’m not too impressed with the Land Institute’s rejoinder to my paper. Rather than offering a measured assessment of my arguments in the round, it’s more of a “Smaje is wrong – now move along, there’s nothing to see here” kind of job, which homes in on a few points where they think my analysis is weak and either ignores or actively distorts the things I’ve written that are more challenging to their programme. You kind of expect that sort of thing in the blogosphere, where I usually live, but I’m a bit disappointed to get the same treatment in an august academic journal. I think perhaps I’m permanently fated to inhabit a nether world in which I’m chastised by some for being a deep green neo-Luddite and by others for being an apologist for agribusiness as usual.

Ah well, understandably the editor of A&SFS doesn’t want a game of academic ping pong so he isn’t giving me an opportunity to respond to the Land Institute’s response. But fortunately I’ve been able to have a word with the editor of Small Farm Future, who agreed to offer me a platform. What a guy. The appearance of my paper is a major publishing event, after all. Well, at least it is for me. So I’ve written no less than four blog posts (excluding this one) about the paper and the debate with the Land Institute which I’ll be posting up in fairly rapid succession here over the next week or so, and then housing in a page of their own on this site. They are:

  1. The strong perennial vision: a critical review and a critical response (in which my paper and the Land Institute’s response are summarised)
  2. The ecology of perennial grains, Or – The strong perennial vision: a response (in which I essay an ecological response to the Land Institute’s response)
  3. Of farming, cereals and civilisations (in which I wax historical and a little political about the Land Institute’s response)
  4. Of Dr Jekyll and Mr Hyde (in which the curious dynamics of the alternative farming movement and its enthusiasm for perennial crops are laid bare)

If you like reading this blog but don’t give a hoot about perennial grain crops, then let me assure you that normal service will be resumed soon. But I hope the posts may be of interest to some. And if not…well, isn’t it just grand to blow off a bit of steam by talking to yourself? After this cycle of posts I’m going to take a couple of weeks off from blogging, and then it’s back to normal – either with an exclusive photo essay on Small Farm Future’s new HQ, or possibly with a post about peasants in 18th century England. Or 20th century China. Or about soil food webs. Or glyphosate. God, it’s endless isn’t it?

References

1. Smaje, C. 2015. ‘The strong perennial vision: a critical review’ Agriculture and Sustainable Food Systems, 39: 471-99.

2. Crews, T. and DeHaan, L. 2015. ‘The strong perennial vision: a response’ Agriculture and Sustainable Food Systems, 39: 500-515.

‘Restoration Agriculture’ Part II: annual monocultures out-calorie perennial polycultures!

In this post, I’m going to complete my look at Mark Shepard’s book Restoration Agriculture: Real World Permaculture for Farmers, which I began in my previous post. My focus here is on Shepard’s analysis of the productivity of perennial polycultures – a subject dear to the heart of many a permaculturist.

In the chapter titled ‘Nutrition and Perennial Agriculture’ (pp.167-183), Shepard writes “The nutrition per acre under restoration agriculture outcompetes corn so much that it’s not even funny” (p.167). Let’s consider this in more detail.

Shepard is actually making three different arguments in this short sentence, two of which I find convincing and one of which I don’t. The first is that a mixed ‘restoration agriculture’ holding produces a more nutritionally complete and balanced diet than a corn monoculture. That’s not something I’ll dispute. Perhaps it’s not something anyone would dispute – I doubt even the most dogmatic proponent of agribusiness-as-usual would argue that a pure corn diet is a good idea. I guess a pure chestnut diet wouldn’t be so great either. But I think it’s true that the mainstream farming system is producing too much of a narrow range of crops which are not nutritionally optimal.

The second argument is that mainstream agriculture wastes a lot of its productivity in inefficient uses: primarily livestock fodder and biofuels. The claim that we need conventional arable annual farming in order to ‘feed the world’ indeed rings hollow when we use so much of its product to feed bio-digesters and livestock that service the demands of the wealthy, and Shepard makes that point convincingly. According to his figures, a corn monoculture can produce 13.9 million calories per acre, but the actual human nutrition derived from it (ie. direct plant food plus indirect food from corn-fed livestock) comes in at only 3.06 million calories per acre. That is a shocking discrepancy indeed, but what are its implications for the calorific productivity of an acre of corn? Zilch. Feed it to livestock, feed it to digesters, dump it in the sea, do any damn fool thing you like with it, but the productivity of a field of corn remains 13.9 million calories per acre. Don’t blame corn for what happens to it beyond the farm gate.

That last point is relevant to Shepard’s third argument, which is that an acre of restoration perennial polyculture outyields an acre of corn calorifically. Calories are important in debating different possible agricultural systems because it’s not an easy thing to get enough energy into the bodies of 7 billion humans, and proposals for agricultural systems that are unable to furnish the necessary calories are not an easy sell. So I’m glad that Shepard has bitten the bullet.

The productivity figure he uses for an annual corn monoculture in his comparison with a perennial polyculture is 3.06 million calories per acre (ie. that proportion of the US corn crop currently used directly for human food – see above). But the one he should be using is 13.9 million calories (the full calorific productivity of an acre of corn – incidentally, I’m mostly just using Shepard’s own reported figures here without corroborating them independently). Let’s now look at Shepard’s perennial productivity figures.

It’s worth pointing out that Shepard’s analysis is not based on actual results from a real live polyculture, but on data aggregated from various sources in the research literature. And it’s also worth pointing out that he’s chosen a maximally energy-productive combination of tree crops, including 86 chestnut trees, 208 hazels and 34 apple trees per acre. He claims a per acre productivity of 1000lbs for the chestnuts, which may not be unreasonable, although elsewhere in the book he states “Out of the thousands of Chinese chestnuts that have been planted at New Forest Farm in the past 15 years, only two of them are bearing” (p.81). This, and a few other considerations, provoke the thought that his reported productivity figures may be a touch on the high side, but let’s take him at his word when he says, in addition to the chestnuts, his system will produce about 2,900lbs of apples per acre, 400lbs of hazelnuts, 400 quarts of raspberries, 5,200lbs of redcurrants and 600lbs of grapes. By his calculations, that amounts to about 4.6 million calories per acre of fruit and nut crops.

There are also livestock grazing on perennial pasture alleys between the fruit and nut crops in Shepard’s system – a dairy cow, a beef steer, two pigs, two sheep and ten chickens, which he estimates will produce about 1,100lbs of meat and 2,100 gallons of milk per acre per year, providing another 1.1 million calories per year. Although he makes some good points about the complementarity of the different livestock species and the high returns from high stocking density, I’ve got to say that I find this an unfeasibly high return of meat and milk to expect to produce each year entirely from a 60x60m plot of perennial forage. But let’s go with it anyway – Shepard’s total system then produces by his estimation about 5.7 million calories per acre.

The conclusion I’d draw from this analysis is that if you choose the most calorifically productive perennial polyculture imaginable and then stretch its projected productivity to or beyond the limit of credulity, you can demonstrate that it’ll produce something like 40% the calories of a corresponding acre of annual corn. So the fact is, despite Shepard’s claims, a perennial polyculture under restoration agriculture is less calorifically productive than an annual monoculture of corn by a distance.

Does it matter? Yes and no, in my opinion. No, because of the following (admittedly simplistic) calculation. Taking the FAO figure of about 3.4×109 acres of arable land globally, and assuming the need for a daily calorific intake of 2200 calories for each of the 7 billion people on the planet, that would require a calorific productivity of about 1.7 million calories per acre – comfortably less than Shepard’s 5.7 million figure. Obviously some parts of the world could probably produce a lot more calories per acre of perennial crops than Shepard’s figure, others a lot less. Anyway, I’m reasonably happy to go along with his fundamental conclusion: yes, we can probably feed the world calorifically (and in every other way) with perennial polycultures. Especially if more people spend a bit more of their time working on them.

But the inferior calorific productivity of perennial polycultures does still matter, if only because there are lots of people in the alternative farming movement – including Mark Shepard – who persist in claiming that perennials outperform annuals on this measure when they manifestly do not. Why bring discredit on ourselves by making claims that are patently false when we don’t even need them to be true in order to justify what we’re doing? That matters.

Shepard draws the following conclusions about his proposed restoration agriculture system (p.180):

  1. It produces more than twice the human calories per acre as an acre of corn
  2. It is perennial and never needs to be planted again
  3. It prevents erosion [and] creates soil
  4. [It] can be managed with no fossil fuel inputs

I’m less sanguine. As I’ve just shown, in fact it produces far fewer calories per acre than corn, though not so few as to undermine its plausibility as an alternative to annual agricultures. Some of it will probably need to be planted again, though admittedly much less than an acre of corn. It will certainly do a better job of preventing erosion (though I do worry a bit about those livestock densities). Creating soil? Well, maybe. And yes it can be managed with no fossil fuel inputs, but then so can an acre of corn. Personally I wouldn’t fancy growing an acre of corn without motorised assistance, but nor would I fancy dealing with 1,400lbs of nuts and 8 or 9,000lbs of fruit.

I’m not sure how the human labour involved in the two cases stacks up. Shepard makes some interesting points about the possibilities, as yet unrealised, of mechanical harvesting in a multistorey perennial polyculture. I think he’s right that this may be possible, though I suspect not easy (surely there will be tradeoffs between the degree of polyculture ‘mimicry’ and ease of harvesting) and probably not especially efficient in terms of energy input/output ratios.

People do tend to wax lyrical about the work-free productivity of forest gardens, fruit forests, perennial polycultures or whatever you want to call them. I’m not yet convinced – I’d like to see some good figures. My sense is that there’s a lot of fiddly work involved in maintaining and harvesting these systems, including managing the successional dynamics of complex polycultures, which tends to go unaccounted in the enthusiasm of their proponents. I think our agrarian ancestors figured out correctly that, in most places at least, the best terms of the input/output equation are to be had from growing annual cereals, in the short run at least. Longer term, that approach has stacked up a host of problems for us, and there’s a lot to be said for moving towards perennial polycultures to remedy them. Increasing calorific productivity or saving ourselves work aren’t, however, among them. That’s why I prefaced this topic in my previous post with that neat quote from the Kansan farmer: “Let us not spend Nature’s accumulated fortune in riotous farming”. My contemporary take on that in the light of Shepard’s analysis would be: “Let us not pretend we can protect Nature’s accumulated fortune while continuing to farm riotously”. Or, “there’s no such thing as a free lunch”. If we’re going to embrace a perennial polycultural agriculture – and Shepard provides a lot of good reasons why we should – then we must also embrace working harder for less return.

Indeed, one of the attractive features about perennial polyculture is its affinity with smaller-scale more rural societies and a more peopled agricultural landscape. Bring it on, I say. But maybe grow a bit of squash along the way. Maybe make some weaker claims for the advantages of perennials and the evils of annuals. Mark, I’m with you most of the way, but I just don’t buy the simplicity of your mantra ‘perennials good, annuals bad’.