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.



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’

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.

8 thoughts on “The strong perennial vision: critical review and critical response

  1. Well, I’ve filled my coffee cup and so hopefully won’t find any need of yawning, but this plant breeder has himself just felt a certain irritation with the hubris of our intrepid Sociologist’s dismissal of the value of breeding contributions to either where we find ourselves now or perhaps more importantly where we might be able to go given the application of the science (and art).

    First off, I think it might be worth expanding the simple dichotomy of GMOs in mainstream ag vs. breeding perennial crops in alternative ag. Though the soy program I work with would be more aligned with the former on paper, we do not use GMO technology to make improvements in plant performance. I don’t want to open the GMO vs non-GMO floodgates here, but if the dam breaks I feel qualified to defend my opinions. Similarly I am not affiliated with the ‘perennials are best’ camp, but I do imagine there is value in pursuing their agenda. The question for me is along a more specific line. Is the value sufficient?

    So I want to come back to the final sentence of the paragraph discussing the present zeitgeist: “While I don’t dispute the vital role of plant breeding, I’m not convinced on either count.” My question now becomes, what evidence do you desire to comfort your soul?

    I will stipulate that unabashed hubris in any human endeavor is unnecessary. And I also want to make sure credit for ‘all-conquering power’ is appropriately distributed to all who deserve recognition for their contributions. Our ancestors who first fell in love with various plant species and through their associations with them brought them to the table (quite literally) have done us a great favor. Next, their descendants who carried said domesticates with them as they moved about the planet also deserve credit for their patience in working with what would now be considered ‘invasive species’ to maintain a relationship they’d become familiar with. Both of these activities – ‘selection’ of endemic partners for domestication, and ‘adaptation’ in novel environments are part and parcel of modern plant breeding. Perhaps claiming selection and adaptation as breeding activities is overdrawn – especially as adaptation can also be facilitated through management. But where I want to head in this comment is toward some objective criteria we might agree upon whereby we could judge the value of breeding activities for their contributions in the past and what hurdles should be jumped in the future to merit some portion of an ‘all-conquering power’ contribution to human survival.

    • Well now Clem, I was expecting a zinger or two from you regarding my comments on plant breeding, and why not? You’re right that the debate is ultimately irresolvable without having some criteria of judgment. But I’d prefer to hold off until my next post, which I hope will set out my stall a bit more clearly. I’ll aim to post it probably tomorrow, after the Small Farm Future legal department have run the rule over it.

      But until then, 3 brief points:

      (1) I think the real crunch question which separates me from the Land Institute is that they think artificial selection renders irrelevant the patterns of ecological and evolutionary constraint conditioning plant forms, whereas I don’t. For them, what happens in the wild has no bearing at all on their project. I don’t see the evidence for this (it also strikes me as a somewhat curious line of argument for people associated with something they call ‘natural systems agriculture’…). To my mind, artificial selection has succeeded largely in augmenting life-history traits already implicit in the plants under selection. Agreed, it would be good to be able to specify this more quantitatively – alas, being neither an ecologist nor an agronomist, I’m not the one to be able to do this. Not sure where you’d stand on this, but I’d be very interested in your comments on my next post if you have the chance to read it.

      (2) As you might expect from me, I don’t really agree with your view that our plant breeding ancestors did us a favour (I don’t think they did us a disfavour either). Perhaps this is also a point of contention between us around plant breeding. I’m inclined to think of plant breeding as a technical craft, like engineering, that addresses itself to specific technical limitations facing us at a given time. Sometimes these engineers succeed in inventing something that overcomes the specific technical problem that they were facing – but to infer that by virtue of that fact they have improved society, brought about ‘progress’ etc is rather a leap of logic. To make such arguments requires a much wider analysis of a kind that I think is ultimately impossible to undertake objectively.

      (3) I respect your insistence on the need to give plant breeding its due, and for calling me to account about its importance. But I stand by my comments about the plant breeding zeitgeist – as you’ve pointed out before, we need to be thinking in terms of participatory breeding, not magic bullets brought down from the mountain by the breeders, as is construed in all too much popular discussion of the topic (GMOs being a case in point here). The lessons of the green revolution need to be learnt. Perhaps I overstate my case against – but when a plant breeder academic referee writes that s/he ‘yawns’ when ecologists discuss constraints and tradeoffs because plant breeders overcome these all the time, I’m afraid my plant breeder hubris alarm starts ringing loudly, and I can’t always turn it off…

  2. Fair enough, I can wait on SFF’s Legal Team and the coming post.

    Your point #2 is interesting, and I suppose not completely surprising. Over the longish run of my career I’ve been witness to conversations in several spheres munching on the notion of exactly what constitutes a breeder. And it does make some sense to limit the definition to an agent who by design sets out to deliberately cross different members of some species with the view to select from among the progeny for a character either not currently on offer – or to enhance some degree of a character. However, this definition builds walls in my experience. I might even suggest this definition can lead to the very ‘yawning’ type of behavior from someone invested in learning of all the design principles; defending the discipline against attacks by the untrained horde. As one’s academic ivory tower comes under siege (whether in reality or merely by appearance) irrational and unkind remarks may flow forth. A regrettable but very predictable aspect of human behavior. So just as ‘yawning’ set off your ‘hubris’ alarm, another might feel alarm at a suggestion of ‘hubris’. Throwing stones because of turf protection?

    By casting a wider net with the definition for our prospective breeder population I run into a different conundrum. Should we gaze back into history and credit our forebears with deliberate design or a role as accidental accomplice in matters of domestication? I feel comfortable suggesting our ancestors made choices – said another way, they ‘selected’ among different elements in their environment. I don’t feel comfortable suggesting these ancestors made these choices with you and me in mind. So the notion of whether or not they did us any favors with the choices they made seems somewhat specious. Perhaps the biggest favor they did us: they survived. By surviving, they left the legacy that has come down over time to be us. You and I are here because they survived. It is now our turn to assess the situation we find ourselves in and make choices. If we make choices that enable our survival it may well come to pass that some future child of our species may look back over our efforts and judge them as favors or blame us. But some future opinion of us seems about as relevant as our present opinion of our ancestors.

    In the narrower description of plant breeder – the ivory tower suspect – the usual calculus for a claim of ‘progress’ is by demonstrating some increase in yield or improvement of some measureable characteristic. If someone else chooses to define ‘progress’ by other metrics then disagreements will follow.

    • Nicely put, and makes sense to me – your points about legacies and survival pretty much encapsulate my views. And you’re right of course about walls coming down. Perhaps I need to be more circumspect in my language.

  3. Chris, I just finished reading Land Institute’s latest report, and they say that “breeding perennials for seed yield can eventually turn it into an annual.” But they argue that it needn’t be the case, because perennials “can do more work than annuals because they process sunlight more days out of the year.” Also, they say they found perennials in Argentina that grow faster than some annuals.

    One thing, though, they are an awesome money machine. People get inspired.

    • Interesting – as I mentioned in my paper, it does seem to me quite likely that breeding for high seed yield in perennials will turn them into annuals. I wrote a bit about the more sunlight harvesting thing in my paper – still not convinced! As I’ve written before, I think the LI over-emphasise the annual-perennial distinction at the expense of growth habit and life history. Your point on the money machine is interesting…

  4. Brian, Any chance that you’ll post that original paper, that the other journal rejected?
    re: “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.”

    • Yes, I suppose I could post the earlier draft. I’ll aim to update this page – including a link to your interesting writing on oligoennials – when I get a chance, hopefully within the next week or so.

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