About twelve thousand years ago, humans hit on a bright idea. Why not grow food in our backyards instead of having to go look for it every time our tummies grumble? It was a masterful stroke of conscious evolution, but hardly a new one. Leaf-cutter ants tapped into sustainable agriculture some 50 million years before us. These busy little beasts spend their days harvesting leaves and trucking them, one-by-one, down, in the ground, to get out, of the rain. Boom boom. But instead of eating the leaves, leaf-cutters masticate them into a thick fluffy paste, spit it into their special growrooms, and fertilize it with their own feces. Before long, the domesticated fungus they adore sprouts forth. These hard-working farmers even evolved fungicides to keep marauding non-edible mushrooms out. Humans farms are pretty fantastic too. Somehow, we manage to feed the vast bloom of global humanity (more or less). But our agricultural techniques require endless inputs: water from far away, petroleum-intensive fertilizers and pesticides that accumulate in our water, soil, and bodies. Meanwhile, the endless rows of identical corn and wheat are dangerously vulnerable to climate change, and glaringly obvious to insects that want to eat them. What can we learn from nature about sustainable farming? Find out in today’s entry of The Biomimicry Manual!
WWI is considered by many to be the dawn of the chemical revolution. That’s when we realized we could really kill a lot of things simply by blasting poison at them. Since then, we’ve gotten ourselves stuck on a “pesticide treadmill.” Insects attack our crops (which are incredibly hard to miss because there’s miles and miles of them and nothing else), so we spray the bejeezus out of them with killer chemicals. Most of them die, but some squeak through to pass on their chemical-resistant genes to the next generation, requiring us to come up with nastier ‘cides. Rinse and repeat ad infinitem, until we poison ourselves and every living thing on earth to death. Mission accomplished: we’re using 3,300% more pesticides since WWI, but the damn bugs just keep on eating.
Humans cultivate some 30,000 edible plants today, but mostly we eat only twenty of those. All are are annuals, meaning, “weedy species that take advantage of bare ground and work fast to make seeds and die.” Over half our calories come from just three of these quickie crops: wheat, rice, and corn. All of humanity is counting on just these, and the UN says two-thirds of the seeds planted in developing countries are “unified strains” with almost no genetic diversity. Geneva…we have a problem. As a species, we’ve built a food system where we are wholly dependent on a handful of identical crops. What if the weather changes? Mother Nature can tell you that betting on things to stay exactly the same is a surefire recipe for a catastrophe when disaster strikes—and it eventually always does.
On the windswept American prairies that came before those endless acres of cornfields, diversity was nature’s best defense. Genetic variation within any species is an insurance policy. When your seeds are essentially clones, a single disease or cold front or drought can wipe you out. But if you’re trying a little of this and a little of that, some of your guys will make it. Fly like a butterfly, sting like a bee— it keeps your enemy confused. A diversity of plant species also works for overall ecosystem productivity. Something is always blooming, sprouting or dying, leaving very little open space for weeds, and shooting out a crazy-quilt of scents and signals for insects to find or avoid. Diversity truly is the cheapest and best pest control.
Prairie diversity boosts productivity in other ways too. Each species has a different root depth, capturing nutrients and water under different conditions. When they do, those inputs are put back into the system. The rich get richer.
If you visit a freshly plowed Kansas wheat field during a spring rainstorm, you will see muddy water streaming off the fields. In just 200 years, a third of our valuable topsoil has gone out to sea. But the wild prairie never gets plowed under: the root system stays intact all year, and soil stays put. The whole thing is like a giant sponge, soaking up rainwater for, well, not a rainy day, but the inevitable summer drought. Prairies have 88 times less run-off than our fields, and deep taproots draw moisture and nutrients all the way down. And fungus! An underground network of “mycorrhizae” (mushroom roots) nestles around the plant roots, plugging every plant into a superhighway of water and nutrients, increasing water-storing capacity ten to a hundred fold. It’s like googling for information instead of randomly taking books off the shelf. It just works better.