A plant breeder thinks he’s changing corn, only to realize it’s changing him
Walter Goldstein became interested in corn in the 1980s.
“I started working with all sorts of corn breeders, I started learning from them, teaching myself how to breed the corn,” he said. “And over the years I started breeding open pollinated corn for farmers that’s varieties that farmers can keep and make their own selections and keep their own seed grow them from year to year, and I kind of fell in love with corn.”
Walter got especially interested in the relationship between corn and nitrogen. Before the 1940s, most corn was open pollinated—meaning farmers could save the seed—and grown without synthetic fertilizer. But in the years since World War II, most of the corn grown in the U.S. has been hybridized so that farmers have to buy new commercial seed each season—and its heavily fertilized with ammonium nitrate, a key ingredient leftover from wartime explosives.
“Now I don’t know if you know but nitrogen fertilizer is a blessing to the extent that it increases yields of our crops, but it’s also a bit of a curse.”
Nitrogen fertilizers cause greenhouse gas emissions and leach nitrates that pollute our wells and rivers and are the cause of ocean dead zones like the one where the Mississippi meets the Gulf. But Walter says we’ve bred corn to need nitrogen fertilizer, and without it most conventional varieties don’t do well.
The corn when we first would get corn, often from conventional breeding programs, which was meant that they were they were breeding them under conditions with lots of nitrogen fertilizer. And when we grew them under our conditions with no fertilizer, they looked they looked pale. They looked as if they weren't getting enough nitrogen. We called it cold turkey. But after we kept those varieties for several years often, not always, but often they began to switch and they began to become more efficient at getting nitrogen.
Walter didn’t know how, or where the plants were getting this nitrogen from. He knew it wasn’t coming from the soil, so it had to be coming from somewhere else.
“And we harvested the seed and we sent it away for analysis for its isotopes because there’s two natural isotopes in the corn, N-14 and N-15 and the balance between them will tell you how much nitrogen has come from the air.” He added, “and they seemed to be getting about half or their nitrogen from the air.”
Somehow, Walter realized, the corn had adapted to this nitrogen deficient soil by starting to fix nitrogen itself.
“The plants themselves were shifting their bodies and their inheritance and their partnerships with microbes in order todo well in the new kinds of environments where we were placing them.”
When he says inheritance, Walter’s talking about to the fact that plants can actually pass beneficial microbes down to the next generation in their seeds.
“And they colonize the rooting zone around the plant. And then they're taken back up by young growing roots where they feed the plant again and then are excreted out again. So it’s like sending the cows out to pasture and milking and pushing them out again. These plants are farmers!”
This realization completely changed the way Walter thinks about corn breeding. Instead of imagining what he wanted from the corn and trying to manipulate it in that direction, he started simply watching.
“So I began to think differently about breeding. It was no longer for me a top-down adventure where I would tell the plants what to do and know what to do as if I was some sort of God. Rather than that it was more or less an exercise in paying attention and trying to do the right thing.”
Walter says this has huge implications for corn breeding. All domesticated plants and animals exist in relationship with humans. But for decades now, our dominant agricultural paradigm has treated them like machines—as if we’re the only ones with the ability to adapt and respond and use creativity. U.S. farmers apply an estimated 5.6 million tons of nitrogen to our corn fields every year —nitrogen that’s wreaking havoc onour air, waters, and soil. We say we have to farm this way to feed ourselves. But Walter no longer believes this is true.
“These varieties are human slash plant creations. They come about because of our values and our interest and because of the plant’s creativity. And they change.”
This piece first aired in October, 2021.