UW scientist on how climate change is impacting soil and the food we grow
David Montgomery is a geomorphologist and a professor of earth and space science at the University of Washington, whose latest book is called A Growing Revolution: Bringing Our Soil Back to Life. He argues that with the onset of climate change our soil is not going to be able to support our food supply, and offers advice for what farmers and gardeners can do about it.
“We think about the atmosphere, we think about energy. But when you look at a food supply, we need healthy, fertile soil to grow enough food to feed us all, and one of the worries that the new I.P.C.C. (Intergovernmental Panel on Climate Change) report … is that atmospheric carbon dioxide levels going up are going to reduce the nutritional value of food into the future,” he told the Candy, Mike and Todd Show.
“It will also reduce the amount of grains that we can harvest and as our population grows, if we’re not able to grow as much food, it gets harder to feed everybody.”
Montgomery says the biggest worry is if climate zones shift such that the same crops can’t be grown in the same regions anymore. Looking down the road, what can people and farmers do to offset the impact of climate change?
“Farming can actually help, and help in ways that will make the farmers themselves more resilient by improving their soil to the point where it can absorb more of the rainfall that falls onto the land, so it doesn’t run off and cause flooding and rain that actually sinks into the ground, that’s what you can actually nourish crops with,” he said.
“So the kind of practices that rebuild soul fertility, which are things like no till, not disturbing the ground, not plowing and digging it up, and in your garden, no double digging.”
Managing soil health also requires covering and a diversity of growth.
“To keep the ground covered–that’s the second principle of managing for soil health — whether in a garden or on a farm — is to always keep a living plant in the ground. Nature doesn’t have a lot of bare earth,” he said.
“The third principle is grow a diversity of things. In a farming context that means crop rotations, that means cover crops, it means planting diverse cover crops in between your cash crops, kind of like planting a native prairie in between your cash crops,” he said. “That can actually be a good way to help rebuild so fertility. And it works in the garden, too.”
Soil depletion in Washington state
In Washington state, the depletion of the quality of soil and depletion of the quality of the crop is an issue which varies depending on where the farm is located.
“It’s kind of different stories on either side of the state. In eastern Washington, studies have looked at the loss of topsoil over the last 100 years of farming. It’s approaching 50 percent in some of those areas, and that’s a big loss in a short period of time,” he said.
“But it’s really differs farm to farm so you can find some farms — whether on the east side or the west side of the state — that are rebuilding fertility and can find others that are degrading it. So the big challenge globally as well as regionally is: How do we encourage farmers to adopt practices that improve the fertility of their land?”
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