Grain farming provides us with calories,
protein, and edible oils (from oil seed crops). But the current
culture of annual spring and summer 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 ground exposed by
tillage less frequently, compared to annual tillage for annual
grains.
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.[source] 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 annual grains, which dodge much pest and disease
susceptibility by going to seed quickly and completely. This uses up
energy put into seed 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.
Please let me explain...
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 grouped into assemblages of
traits which are nearby on a DNA chain, through evolution. 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, then, 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 an ever-changing, overlapping assemblage of plants? This might
yield harvests of mixed seed.
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 holding open a long
window of susceptibility to diseases and pests.
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