What important issues are left out of the conversation about sustainable food? originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.
Answer by Miriam Horn, of the Environmental Defense Fund and author of the recently published Rancher, Farmer, Fisherman: Conservation Heroes of the American Heartland, on Quora.
Thinking about the conversation around sustainable food, the focus on pesticides and synthetic fertilizer has been crucial. Fifty years ago, EDF was founded out of the fight alongside Rachel Carson against the spraying of DDT, which was decimating birds of prey. Today, EDF is leading efforts to reduce the air and water pollution caused by the excessive use of fertilizer, which worsens climate change and causes huge dead zones in places like the Gulf of Mexico.
But other equally crucial issues have gotten far less attention.
First among these is soil health. Though we treat it like dirt, soil is among our most precious resources. It's the largest reservoir of biodiversity, containing a third of the world's organisms, including thousands of species of microbes that play essential roles for life on earth: capturing and ferrying nutrients to plants, protecting plants and animals (including humans) from pests and disease, sustaining photosynthesis, which is the source of all of our oxygen and all of our food.
Soil is also the planet's second largest carbon repository, storing twice as much as our atmosphere and every plant combined. But soil is also terribly endangered. It is essentially nonrenewable, taking some five hundred years to build an inch. Every year, we suffer a net loss worldwide of twenty-three billion tons: one percent of the world's total agricultural soil inventory.
Much of that loss is caused by the most traditional of farming practices: plowing. Tillage can leave soil stripped and highly vulnerable to erosion, or collapsed into hardpan, impermeable to water. Tillage can also do great harm to those microbial communities, scrambling and separating them from their symbiotic partners, and overfeeding them in ways that stimulate bacteria and crowd out more valuable fungi.
A second issue that gets too little attention is biodiversity. Agriculture has already taken over half of all ice-free land on earth, and continues to encroach on the remaining forests and grasslands. We need to limit or even shrink its footprint by being as productive as possible on every acre we use, and we need to farm and ranch and fish in ways that maximize biodiversity on those productive lands and waterways. That includes protecting soil microbes, moving from monoculture to rotation and cover cropping, restoring our vanishing coastal wetlands, which are critical nurseries for most of our seafood, and revising management of our deepwater fisheries to bring back ocean abundance.
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