Better Farm Practices Can Rebuild Soil, Boost Carbon Sequestration
It’s time to stop punishing soils in search of ever-greater crop yields and introduce practices that can restore farmland and soil carbon retention through natural methods, U.S. Department of Agriculture researcher Rick Haney argued last week, in a wide-ranging interview with Yale Environment 360.
“The quest for ever-greater productivity—using fertilizers, herbicides, pesticides, and whatever other chemicals are at hand—is killing our soil and threatening our farms,” Yale states. “Although the United States has some of the richest soils in the world, decades of agricultural abuse have taken their toll, depleting the dirt of essential nutrients and killing off bacteria and fungi that create organic material essential to plants.”
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In the interview, Haney raised the alarm about the rapid loss of soil organic matter over the last 50 years. “We see organic matter levels in some fields of 1% or less,” he said. “Whereas you can go to a pasture sitting right next to it where organics levels are 5% or 6%. That’s how drastically we’ve altered these systems. We’re destroying the organic matter in the soil, and we’ve got to bring that back to sustain life on this planet.”
Haney attributed the rapid decline to excess tillage, lack of cover crops, and high-intensity, chemical-dependent farming practices that “are essentially destroying the functionality of soil, so that you have to feed it more and more synthetic fertilizers just to keep growing this crop.”
The good news, he told Yale, is that “soil will come back if you give it a chance. It’s very robust and resilient. It’s not like we’ve destroyed it to the point where it can’t be fixed.”
But changing course will require an attitude adjustment.
“We had a guy I talked to last week who said, ‘If I adopt these soil health principles, my yields will fall.’ And I said, ‘Yeah, I hope so, I hope everyone’s yields fall.’ There’s just this mindset that we’ve got to increase the yields, increase the yields, increase the yields. You can’t keep doing that.”
Haney warned that the practices he was critiquing reduce the potential for soil carbon sequestration reflected in programs like 4 Pour Mille, a French government initiative introduced at COP 21 in Paris.
“There has been some research showing that these high nitrogen inputs are destroying the carbon in the soil,” he said. “The microbes use up the extra nitrogen, and then they really tear the carbon out, creating lots of CO2, rather than sequestering it in the soil. So there’s evidence that excessive nitrogen actually causes more carbon to leave the system. Whereas we need more carbon in the soil, rather than less.” (h/t to Diane Beckett for pointing us to this story)