Plants are not Accountants, and Heaven can Wait: Perennial Grains Revisited
It’s been about a year since I published my article on perennial grain crops in the journal Agroecology & Sustainable Food Systems1 so maybe it’s time to revisit this teasing topic. Other reasons to return to it…well, I seem to be in the midst of a series of posts on things that are leading us astray from the true path of sustainable agriculture so why not toss another brick onto the barbecue before turning to something more constructive? Then there’s yet another new article, this time in Permaculture Magazine, heralding the imminent solution to the world’s problems once the Land Institute has completed its work on this earth2. Plus ça change. And finally there’s what might be termed blogger’s privilege: for it is a truth universally acknowledged that a disputatious middle-aged man in possession of a blog must be in need of a hobby horse that he can (c)harmlessly ride every now and again when the mood is upon him.
So, to summarise what’s at issue: Take a look at your local wild flora – it mostly comprises perennial plants, which grow prodigiously without anybody destroying the soil through tillage, or going to the trouble of adding fertiliser, pesticides and so forth. Trouble is, it doesn’t produce much to eat. Now take a look at your local arable agriculture – it mostly comprises annual plants, which provide plenty to eat but often at the cost of soil-eating tillage and a load of fertiliser, pesticides and other inputs. Obvious solution: breed perennial varieties of edible arable crops, and you get the best of both worlds.
There’s a problem though. Plant breeders have been trying this for well over a century, and the results aren’t much to write home about. They’ve managed to breed plants with good perenniality but poor edible seed yield, and plants with good edible seed yield but poor perenniality. Plants with good perenniality and good edible seed yield, though? Not so much. Patience, patience, say the plant breeders at the Land Institute, probably the world’s premier perennial grain research organisation. This is a project of ‘deep permaculture’3. Don’t expect it to bear fruit overnight. But expect it to bear fruit eventually – and when it does, we’ll be able to grow soil-conserving, self-fertilising, pest-resistant, perennial grain polycultures that yield just as much as our present annual grain cultures, but without all the environmental costs associated with them.
Nice. Except I think it’s a fantasy. Not that fantasies are necessarily bad things. I think it’s good that the Land Institute are working on this stuff. I doubt that they’ll find their perennial grain holy grail, but you never know, they just might. And even if they don’t, they’ll probably come up with other useful things. So more power to them. Except that…well, despite being every permaculturist’s favourite scientists, including mine not so long ago, I’ve fallen a little bit out of love with the folks at the Land Institute because…because…OK, out with it…because they’re so damned dismissive of essentially every other approach that anyone tries to take towards a sustainable agriculture, and because they’re so unscientifically cocksure about the correctness of their approach despite their unimpressive results to date that they feel the need to fill the pages of periodicals both scientific and popular with more blandishments about what they’re going to achieve than any solid information about what they actually have achieved.
I’ve written at some length elsewhere about why breeding high-yielding perennial grains is such a tall order4, and I’m not going to go into the details again here. But, prompted by the latest bout of enthusiasm for perennial grains in Permaculture Magazine, I’d like to present brief arguments from five perspectives as to why I struggle to find a great deal of enthusiasm for what the Land Institute are doing.
1. Plants are not accountants: an argument from plant ecology
Perennial grain breeder Peggy Wagoner published a comprehensive review of achievements in the field to date in 19905, in which she stated “the resources available for seed production in a perennial appear to be less than in an annual.” Those seventeen words pretty much encapsulate my take on the issue. Wagoner, I think, is right, and I’m doubtful that any amount of genetic twiddling by plant breeders is ultimately going to overcome that basic truth.
Land Institute scientists take a different view, and indeed flatly contradicted Wagoner’s contention in a 2007 book chapter6. The debate has been a largely theoretical rather than an empirical one, focusing on whether it’s conceptually plausible for a perennial grass to produce as much edible starchy matter in the form of seeds as an annual grass while maintaining perenniality. Producing energy-rich seeds is, after all, energetically costly to the plant, and so is producing perennating structures that enable it to survive year after year.
The Land Institute have a fancy scientific rationale for their view, and a regular workaday one – neither of which I personally find convincing. The fancy one has to do with quantitative genetic trade-off theory – a red herring in my opinion, for reasons outlined in my article. In their response to the article7, the Land Institute authors ignored this part of my critique altogether…suggesting to me that perhaps I’m onto something. But I hope someday I’ll get some feedback on it from a neutral party with a stronger grounding in genetics than me. The workaday one, repeated in the Permaculture Magazine article, is that – being better established from the get-go – perennial plants are able to harvest more sunlight over the course of the year than annuals, and are therefore able to “pay the energetic cost of perennation”8.
That sounds plausible, even if it’s doubtful that perennials always harvest more light than annuals. But metaphors can mislead. Plants aren’t accountants who check their bank accounts at the end of the financial year, pay their debts, and then spend off the balance as they wish. They’re organisms, like us, who are pursuing longer term projects. And the long-term project of a perennial plant is to keep on living rather than punting scarce resources on reckless acts of maximal reproduction. When the firm has had a good year and everyone’s flush with their bonus, the perennials may have an extra half glass of wine at the Christmas party but they’re not going to join in with the carousing annuals, waving their wads at the barman and ending up on the carpet at the end of the evening. Doubtless plant breeders can mix things up and introduce a bit more of that annual swagger into their perennial charges. If things go well, they may even get both good seed yield and good perennation for a year or two. But I suspect that sooner or later, and probably sooner, this new breed of wad-waving perennials will end up on the carpet along with their annual buddies. That, essentially, is what Wagoner reported empirically, and despite the Land Institute’s outright dismissal of her analysis, and of mine, I’ve not yet seen any very convincing results to suggest otherwise (I’ve only been able to access the abstract from the Land Institute’s latest publication on a lack of correlation between seed yield and (short-term) survival in Sorghum bicolor x S. halepense crosses but, as with an earlier study9, it seems unclear what longer-term survival is and whether allometry is controlled).
2. Never walk alone: the argument from history
But maybe I’m overdoing this whole annual versus perennial growth habit thing. The Land Institute folks certainly think so, writing in response to my article that “There are as many life history patterns as there are species”7. Except there aren’t. Not really. I think plant ecologist Phil Grime is more on the money when he says that the outcomes of natural selection are restricted to a rather narrow range of basic alternatives in life-history, resource allocation and physiology10. Which is basically my point, and which explains Wagoner’s finding. I’m glossing a lot of detail here, which can be found in this blog post and in my original article1, but that’s the long and the short of it.
Suppose the Land Institute were right, though. Suppose it’s true that there are as many life history patterns as there are species. Then you’d surely expect to find some long-lived herbaceous perennials somewhere in the world with high allocations to starchy, edible seeds, and you’d surely expect that over the 10,000+ year history of human agriculture somebody would have run across them at some point and incorporated them into the human agricultural package. But it doesn’t seem to have happened. In their reply to my article, the most compelling counter-evidence to my arguments marshalled by the Land Institute authors is some early successional perennial sunflowers (early successional, note…) that have a higher sexual allocation than their annual counterparts. For an institute that’s being going at this problem for forty years, this seems to me a pretty weak result to hang your research rationale on, as I argue in more detail here.
I think this issue of the lack of high yielding perennial grains throughout agricultural history is a bit of a problem for the Land Institute’s line of argument, because if there are no fundamental ecological obstacles to producing such a plant then it’s curious that it hasn’t yet happened. A lengthy paper by Land Institute plant breeders in the scholarly journal Evolutionary Applications argues that there were various compelling reasons why the early agriculturists opted for annual crops despite the lack of fundamental obstacles to perennial ones, and this sent humanity off down a blind alley which it followed religiously for ten millennia until modern perennial grain breeders appeared on the scene11. It’s an interesting paper, but an ultimately obfuscatory one, I think – the ‘backing the wrong horse’ historical argument tries to get the case for high-yielding perennial grains off a tricky historical hook. But I don’t think it really succeeds.
3. The argument from human ecology
Anyway, what’s so great about high yielding cereal crops? As I argue in this article, the world has become increasingly reliant on a torrent of cheap grain from the semi-arid continental grassland regions. The countries that have put serious effort into perennial grain research are all major grain exporters, and grain exports have had the effect of undermining more local small-scale agricultures and hustling populations into grain import dependent cities. So if it turns out that in order to conserve soils in the semi-arid continental grasslands it’s necessary to grow perennial grains with a lower yield than annual ones, thereby lowering grain exports from these regions, that would be a felicitous result for creating a more sustainable world. The Land Institute has already produced edible perennial grains, albeit ones with a much lower yield than their annual counterparts. Excellent stuff. You can stop now, your work is done!
Incidentally, as the aforementioned Phil Grime explains in a note on my website (available from here), there was interest in the 1960s in producing energy-rich food out of leafy rather than seedy perennial matter. This is a much more ecologically plausible way of teasing nutrition out of herbaceous perennials. But then along came Norman Borlaug and the Green Revolution, where the strategy was to max out on the seedy potentiality of annual cereals, with short-straw, high nutrient responsive annual varieties – very clever, if ultimately somewhat questionable in its achievements, but illustrative I think of how much easier it is to push plants in directions they’re already ecologically predisposed to go in (the Green Revolution) than to push them in the opposite direction while trying to maintain key original traits (perennial grain breeding).
4. Heaven can wait: the argument from farm ecology
In the 2007 article that I mentioned above6, Land Institute breeders wrote “In sparsely distributed garden-sized patches, annual grains would have limited negative impact”, which strikes me as plausible. If your farming involves small, carefully-sited areas of tillage within a larger context of perennial and annual cover cropping, water management, wind protection and so forth, then it seems to me that annual grains would indeed have limited negative impact – especially in areas such as here in northwest Europe where rainfall isn’t especially erosive. Such farming is eminently achievable right now, without any further technical or plant-breeding innovations – a minimally destructive small farm future is right here within our grasp.
But Land Institute scientists now appear to have reneged on their earlier position – for example, in the recent Permaculture Magazine article in which Tim Crews is quoted as saying “In terms of carbon loss and nutrient leakage, if you open up 3x3m (10x10ft), it is going to take place whether you are a postage stamp gardener or not”12. Well, maybe so but is there not greater potential to check such losses in a farmed landscape with millions of people working small plots than there is in a landscape where you have a couple of tractor drivers tending thousands of acres? And even if there isn’t, might there be greater future potential for finding ways of preventing these losses on small-scale farms at the level of whole farm design than in finding the holy grail of a productive perennial polyculture? Crews talks as if developing perennial polycultures is the only viable way of devising a sustainable agriculture, without providing any evidence for this view.
It’s here that I start to find the Land Institute position a bit annoying. It’s like trying to talk trade-offs with a nuclear fusion nerd. Suppose I’ve got gas heating in my house, and I invest in cavity wall insulation to decrease my gas consumption. “You’re wasting your time,” says the fusion fan. “You’re still using gas, which is a bad, bad thing. And in a few decades we’re going to have figured out fusion, giving us unlimited clean energy. So you’re barking up the wrong tree with your silly insulation.”
Well, nuclear fusion isn’t here yet, and nor are productive perennial grain polycultures, so in the meantime why not try to get by as best we can in limiting the damage? A high yielding and sustainable perennial (grain) polyculture may be the gold standard, but we may never attain it and it may turn out that we get a decent bang for our buck taking other approaches. Heaven can wait. Perhaps in the long run annual agriculture may not be a sustainable strategy for humanity. But in the short run couldn’t the Land Institute just get off the backs of people trying to make their farming as sustainable as they possibly can, and accept that there are different paths to sustainability that are worth exploring? That way, it’ll spare us the frustrating experience of hosting permaculture visitors who look disdainfully at the wheat or potatoes in our rotations while citing the Land Institute as an example of what we should be doing. Though why the ‘domestic prairie’ it’s seeking is regarded as an example of permaculture nature mimicry beats me, since by its own admission what it’s trying to create is unprecedented in biological history.
5. The emperor’s clothes: the argument from scientific humility
And finally, talk of biological history makes me think of Charles Darwin. His theory of evolution by natural selection was a big shout, and it took him twenty odd years in between first formulating the elements of the theory in his mind and actually formalising it with the publication of his Origin of Species in 1859. What he didn’t do in the course of those twenty years was publish (or cause his acolytes to publish) an endless stream of data-light articles about how he’d figured out this great approach that was going to upturn everything people thought about biology, and though he hadn’t quite put all the details together yet, this was going to be really, really big at some point in the future.
No doubt perennial grain breeders are under the same pressures as other researchers to secure funding by talking up their approach. But I suspect that if they overplay their hand it may backfire. At some point somebody may yell that the emperor has no clothes. In a blog post, Land Institute breeder David Van Tassel wrote, “getting perennial plants to reallocate massively to sexual structures is a huge challenge….It may prove impossible”13. Hallelujah! More of that please. It doesn’t mean that they shouldn’t be doing what they’re doing. It just means that they’d be going about their business like proper scientists should – with circumspection, humility and the consciousness that their approach could prove wrongheaded and that other approaches may have something to contribute.
Here are some suggested lines for Land Institute scientists to voice in the next article somebody writes about them:
“Peggy Wagoner wrote that ‘the resources available for seed production in a perennial appear to be less than in an annual’. We think she could be wrong when it comes to edible perennial grains, though we haven’t proved it yet. There are difficult genetic, ecological and agronomic obstacles to overcome in developing a sustainable and high-yielding perennial grain polyculture, but we think it’s worth trying to overcome them. Other people are trying to overcome the problems of agriculture in other ways. Nobody can yet tell which – if any – ways will prove effective, but in agricultural research as well as in agriculture it pays not to put all your eggs in one basket, so we welcome these other approaches. In the meantime, we plan to continue with our research and to publish data on our perennial grain yields and the longevity of the crops in question in all of our publications”.
It would be a fine thing if the Land Institute could see its way to endorsing such a statement. Unfortunately, the Permaculture Magazine article reports that the Bill and Melinda Gates Foundation is now investing in perennial grain research. So I guess we can forget about circumspection, humility or the possibility of being wrong in this area.
It just remains for me to thank anyone who’s succeeded in reading this far, and to let you know that I feel sooo much better now I’ve got all that off my chest.
- Smaje, C. (2015). The strong perennial vision: a critical review. Agroecology & Sustainable Food Systems, 39: 471-99.
- Bird, W. (2016) ‘Perennial grain research’ Permaculture Magazine, 87: 61-3.
- Ibid. p.61.
- See reference 1, and writings summarised at http://smallfarmfuture.org.uk/?page_id=714
- Wagoner, P. (1990). Perennial grain development— Past efforts and potential for the future. Critical Reviews in Plant Sciences, 9: 381–408.
- DeHaan, L. et al. (2007). Perennial grains. In Farming with nature: The science and practice of eco-agriculture, eds. S. Scherr and J. McNeely, 61–82. Washington, DC: Island Press.
- Crews T. & DeHaan, L. (2015) The strong perennial vision: a response. Agroecology & Sustainable Food Systems, 39: 500-515.
- DeHaan, L. et al. 2005. Perennial grain crops: A synthesis of ecology and plant breeding. Renewable Agriculture and Food Systems 20: 5–14.
- Piper, J., & P. Kulakow. 1994. Seed yield and biomass allocation in Sorghum bicolor and F1 and backcross generations of S. bicolor x S. halepense hybrids. Canadian Journal of Botany 72:468–474.
- Grime, J. & S. Pierce. 2012. The evolutionary strategies that shape ecosystems. Oxford, UK: Wiley-Blackwell.
- Van Tassel, D. et al. 2010. Missing domesticated plant forms: can artiﬁcial selection ﬁll the gap? Evolutionary Applications 3: 434–452.
- Bird, op cit. p.62.
- Van Tassel, D. 2012. Tradeoff or payoff? http://perennialgrainresearch.blogspot.co. uk/2012/11/biomass-accumulation-by-miscanthus-in.html
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