As I walk through the broomsedge in June, dozens of grasshoppers clatter
away with every footstep. Bees and wasps wing past, leafhoppers spring,
and beetles scurry for cover. This productivity is why so many birds
depend on grasslands for their breeding or wintering. Grasslands,
especially those in humid areas with good soil, provision their local
food webs as richly as do forests.
Grasses also build soil. Their leaves send about two thirds of all
the food they make to the underworld. There, roots tunnel many meters
down. As they grow, they break up clay and rock, exude sugars and other
molecules, and interweave their cells with fungi. When the roots die,
they add spongy organic matter to the soil. This soil‑building process
is so productive that it lifts the ground. When a degraded grassland
returns to health, the ground heaves up, as if inhaling with relief. In
old grasslands, the soil can be rich with organic matter to a depth of
several meters. When prairie goes under the plow, most of the organic
matter disappears, turning living water‑holding, nutrient‑rich soil into
mineral dust. Today, despite widespread degradation of grasslands, one
third of all carbon stored on land is still locked up in grassland
soils.
As fellow volunteers, the staff of Birds Georgia and I sow grass
seed, we enact the grassland ethos: Build community, one species helping
another. Grasses are creators. They use cooperative partnerships to
build their homes, places that, in turn, open possibilities for others.
They hoard soil carbon, create habitat for other plants, and feed
animals.
Grasses are creators. They use cooperative
partnerships to build their homes, places that, in turn, open
possibilities for others.
Although we don’t often imagine ourselves in this way, we are a prime beneficiary, a species built by grass.
What’s for dinner? Grass. Wherever you live, some kind of grass is probably feeding you.
When the prophet Isaiah proclaimed that “all flesh is grass,” he
intended a commentary on the fleeting nature of human life, but he also
spoke an ecological truth. In Isaiah’s time and in ours, grass sustains
us. If we stacked in 50‑kilogram sacks the total cereal harvest in 2023,
the pile would reach to the moon forty times. That’s 2,836 million
metric tons of grass flowers matured into seed. Three grasses—rice,
maize, and wheat—account for 90 percent of this superabundance,
supplying us with two thirds of food calories. The juices of sugarcane,
another grass, supply another 1,900 million metric tons. Barley,
sorghum, oats, millet, rye, and wild rice are grasses, too.
Livestock fattens on grass from pasture and the maize‑filled troughs
of feedlots. While our great ape cousins feed on forest fruits, leaves,
and animal prey, we depend on grasses. If we named ourselves for our
primary food, we would be grass apes, Homo poaceae, for Poaceae, the scientific name for the grass family, from the ancient Greek for “fodder.”
It is the nutritive gifts of grasses, with help from oil‑rich fruits
like mustards and oil palms, that caused the increase in food calories
available to humans over the last millennium and, especially, the last
century. The cereal harvest in 2023 was 50 percent higher than that of
2000 and three times that of the 1960s, outpacing human population
growth on all continents. Famines are rarer than they were and now
largely emerge from human injustice and war, not the failure of plants
to yield food. Such productivity comes with severe costs: felled forest,
mined and synthesized fertilizer, among many. But those who in the
nineteenth and twentieth centuries made erroneous predictions of
imminent mass starvation erred by underestimating the world‑changing
potential of grasses.
These global patterns are evident in kitchens. At home, the bottom
drawer of our kitchen cabinet grinds when I pull it open. The poor thing
has worn sliders and is loaded with bags and tubs. Bread flour, whole
wheat flour, all‑purpose white flour, masa, purple cornmeal,
medium‑ground yellow cornmeal, plain fine cornmeal, semolina flour,
barley flour, and sorghum flour. Some are baking staples, ingredients
for pancakes, loaves, and corn breads.
Others are aspirational, plucked in moments of enthusiasm as Katie
and I push our cart through the aisles of the Dekalb Farmers Market, a
bustling warehouse near our home stocked with bulk dried goods and fresh
produce from across the globe. Regardless of their origin, every one of
the flours in our kitchen drawer is ground‑up grass seed, the product
of a mature grass flower. Other kitchen drawers hold rice and pasta,
also made from grass seed. Our kitchen, like kitchens over much of the
world, is a bouquet of grass.
From the three hundred thousand species of flowering plants on Earth,
we’ve plucked a handful of grasses and founded modern agriculture on
their productivity. What made grass so special? The answers reveal not
only why we latched onto them so firmly, but also how grasses managed to
take over much of the planet long before humans evolved.
Grass flowers are super‑mothers, giving their embryos ample
provisions. Under a magnifying glass we can see how. I pull open the
complaining kitchen drawer and dip a teaspoon into some bags, retrieving
flours that I dust onto scrap paper under a bright counter light. What
looked to my unaided eye like powders of different colors reveal
themselves under the lens as diverse and beautiful. I expected white
flour to look fluffy, but magnified it looks like coral sand. I smooth
the tiny pile with the back of my spoon and the flour becomes a
miniature tropical beach, a gleaming expanse enlivened with a scattering
of darker grains.
Whole wheat flour seems made of tan‑colored sand mixed with shredded
cardboard, as if a hurricane had passed through a shipping warehouse on
its way to the beach. The grains of purple cornmeal are larger than
those of the wheat flours and are intermixed with white‑blue pebbles and
chunks of broken obsidian. Uncooked rice grains loom over these sands.
They are slightly translucent and etched with lines, as if ancient
Egyptians had built their obelisks from milky glass. Who needs magic
mushrooms when we have 7× hand lenses?....
