Monday, June 06, 2016

Raising Grain.

    Grain farming provides us with calories, protein, and edible oils (from oil seed crops). But the current culture of annual spring grain crops, (and ‘biennial’ winter grain crops) uses lots of energy-intensive plowing and cultivating, leading to wind and water erosion of our practically irreplaceable topsoil.

    Enter the dream of perennial grains, that would yield year-after-year continuously, and catch the spring sunlight that annual grain plants are still too small and young to intercept. By catching more sunlight, perennial grains might both yield well and have energy reserves to fight off diseases and such, to survive and yield for many years. Perennial grains could also preserve soil from erosion, by leaving little ground exposed by tillage, compared to frequent tillage for annual grains, at least in theory.

    In practice, according to Rodale’s Peggy Wagoner, attempts at perennial grains have yielded either lots for a few years or little for many years. This may be because of the different life strategies of massively-seed-yielding annuals versus massively-pest-resistant perennials. To explain, perennials face a longer window of disease and pest susceptibility. Their perennial life strategy is a gamble that they can do better than annuals by setting seed years from now, instead of this year (or next). To hedge their bet, they invest energy resources in preparing to fight, and actually fighting off, diseases and pests. This leaves less energy to build big seed yield in early life.

    This contrasts with heavy-yielding spring and winter grains, which dodge much pest and disease susceptibility by going to seed quickly and completely. This uses up energy that might have otherwise been available for weathering the long multi-year windows of disease and pest susceptibility faced by perennials. Is there a reason that it has been so difficult to combine large yearly seed yields with long life? Perhaps there has been both evolution of traits valuable for either lifestyle, as well as evolution of assemblages of these traits.

    DNA (deoxyribonucleic acid) encodes traits in specific locations within chromosome chains. Maybe traits useful for either one lifestyle or another; either annual or perennial, have evolved to be grouped into assemblages of traits nearby on the DNA chain. They might tend to have evolved to be in two groups, one for each lifestyle, because plants did well with either one assemblage, say annual, or the other, perennial, but plants with mixed traits did poorly, and left relatively less mixed-trait offspring. This can explain why it’s been so difficult to combine heavy, constant yields and long life in grains.

    Is the dream of having living roots continually holding soil while yielding grain year-after-year practically impossible? Is there any way to use what we have created; short-lived heavy-yielding grains and long-lived, light-yielding grains, to piece together some method that can sustain itself, while sustaining humanity?

    Masanobu Fukuoka sowed winter grain into ripening rice in autumn, then, a couple of weeks later, he harvested the rice, leaving the winter grain growing with a head-start on the weeds. Late next spring, he then sowed rice into the ripening winter grain before harvesting the winter grain, so the rice growing in the stubble also had a head-start on weeds. This model of staggering two short-lived grains growing together to continually hold the soil might guide us.

    A part of Fukuoka’s method may be hand-harvesting - heavy mechanical combines might crush the young sprouts beneath the ripe standing ready-to-harvest crop. Can we overlap a set of the short-lived high-yielding perennial grains that Wagoner documented, to have living roots continually holding soil, but by a changing assemblage of plants? This might yield mixed-type harvests.

    Can we sort, after harvest, different grains mixed within the same year’s harvest, or use them mixed together? We now sort weed seed from grain commercially, so separating differently sized grains seems do-able.

    If this works, we might succeed at getting harvests of grain while living roots continually hold grain field soil, yet without any one grain opening a long window of susceptibility to diseases and pests.

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