Friday, March 25, 2016

Splitting the Difference with Somewhat-Perennial Grains

Splitting the Difference with Somewhat-Perennial Grains

    The difference being split here is between grain crops that live less than a year and long-lived crop relatives that persist over a decade. It is the difference between traditional grain crops and the perennial relatives under development for ongoing grain yields every year. The word ‘perennial’ has two meaning that contrast here; it means ‘year-after-year on an ongoing basis’ as used generally, and means ‘surviving more than a couple of years’ in a botanical sense. I accentuate this distinction because of the importance of crop relatives that ‘split the difference’ - they persist more than a couple of years, yet die out over a decade or more. But first a review of other competitive approaches.
    Most grain crops are annual or biennial. There are annual spring barley, oats, wheat and rye, as well as winter rye, barley and wheat, that can be considered biennial, as they survive a winter. After these crops ripen and are harvested, the ground is traditionally plowed and another crop sown. This kills weeds, but allows erosion of soil, as before the newly sown crop grows roots, the soil is not held in place by any living roots.
    Why not just use long-lived perennial relatives of our crops instead, as The Land Institute strives to do? Wes Jackson’s institute has striven to produce perennial grains that would yield lots of useful grain year-after-year, without yearly plowing. They’ve been cross-breeding our annual grain crops with their wild, perennial relatives, striving to combine long life with heavy yield. They hope to develop crops which yield well every year, while the living roots permanently hold the soil from eroding. But it has been difficult. They have been breeding plants for decades. While the dream of everlasting yields from one planting has drawn interest perennially, the work has been hard.
    The problem may lie in strong genetic linkages between, first, traits that we hope to combine, and second, traits that we hope to omit. We want large yields and long life. But long life provides an extended window of disease and pest susceptibility. Long-lived plants survive these long susceptibility windows by guiding energy to defense, energy that could have gone to large yields, as in our short-lived crops. Since there’s a limited amount of sunlight energy caught by any plant, there must be a choice between defense and reproduction - and this choice has been faced by our crops and their wild relatives for eons; faced for so long that clusters of these traits may have evolved to be tightly bound together, so that a plant either prepares to withstand long windows of susceptibility, or commits itself to forming lots of offspring rapidly, but not both. Breaking these genetic linkages may be the difficult challenge of The Land Institute’s approach.
    Let’s look a bit afield, for inspiration:
    1. Some varieties of biennial winter grains will not go to seed until they’ve experienced a winter, even if first planted three seasons earlier, in spring. But most crops are annuals, and die after going to seed.
    2. There are crop wild relatives that are not quite as short-lived as annuals, yet are still pioneer species adapted to large seed yields and short life spans, unlike long-lived perennials. For example barley, Hordeum vulgare, is closely related to Hordeum bulbosum, a short-lived perennial with large yields of big, heavy seed, which crosses with barley. And rye, Secale cereale has a relative, Secale montanum, that also colonizes disturbed soils for a few years, via its large seed yield of heavy seed.
    3. Farmers sometimes ‘oversow’ seed for a following crop above the previous standing crop, before harvesting the standing crop. This leaves the ‘oversown’ crop with a head-start on any weeds that start to grow after the previous crop’s harvest, if everything works out.
    4. Shingles protect an entire roof, yet each shingle is shorter than the whole roof.
    In light of these four factoids, perhaps there’s another way that splits the difference between annuals and long-lived perennials. Perhaps we can conceed long life, because what we really want is living roots always holding the soil. Could we have a constantly-changing succession of plants growing roots that protect soil over the duration, like a roof, yet with each crop itself only surviving a short portion of that time, like a roof shingle? Perhaps we can have living roots constantly holding soil, yet have those roots grow, not from one long-lived crop, but from an overlapping series of short-lived crops, growing one after another. If these crops overlap their times in the field, one crop’s roots can grow in as a previous crop’s roots die, so that soil is always held by living roots. Thus, like shingles, each crop’s life is short, yet together their roots hold soil for the duration. This is a central concept to an alternate approach that might be called ‘somewhat-perennial grains.’
    As an aside, these two wild relatives, Hordeum bulbosum and Secale montanum, share an adaptation; a means of seed dispersal. They form seedheads which get stuck, via long spiny parts, to the fur of animals that travel and distribute that seed. Fur-zoochory or animal-fur-borne dispersal of seed, allows the seed to be heavy, compared to wind-dispersed seed, and still disperse. This seed density may have been very attractive to early humans, because they could easily winnow apart heavy seed from light chaff. Perhaps early animal herders protected their flocks in night paddocks, which got grazed down, manured and seeded to these wild crop relatives via fur-zoochory. Then perhaps Hordeum species grew and set much seed, and people harvested it, liked it, understood what happened, and learned to sow to repeat this feat. In any case, fur-zoochory in crop relatives may signal usefulness in somewhat-perennial grain cultures.
    ‘Grains’ here means seed crops, and includes peas, lentils, edible vetches and chickpeas and their wild relatives, as well as flax, sunflower and the like. And as folks at The Land Institute have so ably envisioned, polycultures of somewhat-perennial grains could include:
    1. summer-adapted grasses, like sorghum, maize and millet, and their wild relatives,
    2. cool-season-adapted grasses like barley, wheat, rye and oats, and their relatives,
    3. composites, like sunflower, and relatives, and
    4. legumes like peas, lentils, vetch and chickpeas, and their relatives. These could grow together, and their seed could perhaps be separated by shape, size and density, if harvested together, or could be used together.
    In sum, some short-lived wild grain relatives (with lifespans in the single digits) might help form a more sustainable agriculture that would use plowing only rarely. These grain relatives might be over-sown into ripening crops before the earlier crop's harvest, to allow the over-sown crop a head-start over weeds. Like shingles shielding a roof, these crops together might protect soil over an extended duration, while yielding year after year, yet without any one crop presenting a long window of vulnerability to pests and disease.


Craig Hepworth said...

Great article, Brian! I love the ideas explored here. I'd love to see someone working on this. Masanobu Fukuoka claimed to have perfected a system that did something along these lines using annual grains: he'd grow rice in the summer, and towards the end of its life cycle, he'd sow winter grain, barley I think, among the rice, which would germinate among the rice plants. Then in spring, he'd sow rice among the barley plants. I think he used clay seed balls. Doing something similar with semi-perennials would presumably mean more extensive root systems in the soil, and less opportunity for weeds to establish during the times between when each crop has full coverage.
For the short-lived perennial relatives of grain crops you mentioned, Hordeum bulbosum and Secale montanum, do you know if they make heavy crops every year for their lifespan of several years, or do they save up their energy for several years for one big flowering-and-fruiting event?

Craig Hepworth said...
This comment has been removed by the author.
Brian Cady said...

Hi Craig,

Hordeum bulbosum and Secale montanum set seed yearly, not like bamboo's long flowering cycles, I believe. Fukuoka's work is an inspiration.

Brian Cady said...

Hi Shark,

It's me, Brian, author. Thanks for your interest. I guess my writing really failed since you've read it twice and etc. Fukuoka's work is an inspiration. The distinction between the One-Straw approach and this is the length of life of the plants involved. Fukuoka used annuals and biennials (the winter grains), while somewhat-perennial grains would use short-lived perennials; crop-relative grasses that typically survive a few years, setting seed a few times. Does that help?

Jason Padvorac said...

I really like the shingle analogy. And the idea that shortlived perennial grains -- if properly managed -- might provide very similar or the same benefits as long-lived perennials. Thanks for writing this up!

I think the tricky thing to learn would be how to manage reseeding so that plants were replaced as needed, without overseeding. Possibly John Jeavon's biointensive style transplanting just to fill gaps. That would be labor intensive, of course, but would be workable on human scale plots.