By Tamar Haspel
As climate change climbs the chart of existential threats, soil is getting a lot of attention. Back when it supported forest or grassland, before we cleared it to grow crops, it stored an awful lot of carbon.
By farming the land, we released the carbon. Now, there’s a major push to figure out how to put at least some of it back. The Land Institute, in Salina, Kan., is on it, and I visited them last fall. “We lost about half the carbon in the first few decades after putting crops on prairie,” said Land Institute President Fred Iutzi, who was showing me around. “In some places it leveled off at about half of what was there pre-settlement, on some places it went down to about a third.”
Carbon loss dates back to the first time a farmer ever turned over virgin soil, but it’s only in the past couple of decades that momentum has built among farmers and researchers trying to reverse things. There’s a major obstacle, though: 400 million (ish) acres of annuals, crops that have to be planted anew every year. While annuals are very good at growing seeds (usually the plant part we eat), they’re not so good at locking carbon in the soil. In fact, they’re pretty bad at it.
The Land Institute is trying to solve that problem by developing perennial grains: crops that come up, year after year, of their own accord. A commercial variety is years — and possibly decades — away, but consider that it took us about 80 years to get from corn that yielded 25 bushels an acre to corn that yields 170 bushels an acre. It’s not unreasonable to take a couple decades to catch up.