Soil carbon, climate among global changes impacting agriculture

More carbon in the air means less in the ground, and for farmers, that's bad news, said a local researcher studying how climate change is impacting agriculture.

In Washington state, more than 90 million metric tons of carbon dioxide are released annually into the air. Globally, most scientists connect carbon-dioxide emissions and other greenhouse gases to global warming and climate change.

While modern farming methods are partly to blame, the real concern is what effect climate change could have on local agriculture, and from there, on the regional economy.

About 600 farmers attending last week's Focus on Farming conference heard Chad Kruger speak on the future of farming in temperatures that have grown warmer each year since the beginning of the 20th century. Kruger works at Washington State University's Center for Sustaining Agriculture and Natural Resources.

Tillage has helped release carbon into the air, and levels found in the top foot of soils are expected to continue dropping through at least the year 2040, Kruger said. Worse, when you lose the carbon in the soil — a key ingredient for plant growth — you also lose natural nitrogen, another necessity to healthy crops.

"We've masked that with artificial fertilizers, but as fertilizers increase in price, we'll see that become an issue," Kruger said.

Fertilizer prices will continue climbing in the United States if the nation doesn't lessen its demand for oil. Fertilizer is a petroleum-based product, said Fred Kirschenmann, a farmer working at Iowa State University's Leopold Center for Sustainable Agriculture.

The mass dependance on oil also is adding to greenhouse-gas emissions responsible for climate change, Kirschenmann said, and a move to alternative fuels would help tremendously. It also would help local farmers if they can begin growing seeds for biodiesel products.

Snohomish County already is using about 250 acres to test various seed crops for biodiesel.

One farmer who could benefit from new crops is Dale Reiner, of Monroe, who has 35 acres of canola.

"We should be looking at ways to put up with future [climate] changes," Reiner said. "That's presuming we can change the direction of global warming, and I'm not sure we can, but we at least need to try."

One result of global warming, Kruger said, has been higher annual temperatures in the Puget Sound region. If that continues, there will be less snow and more melt-off earlier in the season, prompting crop-rotation changes. Less water would be available during the summer for irrigation, and the spring months would be more prone to flooding.

Already, severe flooding has put some area farmers out of business.

"Flooding has to be a large contributor to the decrease of Snohomish County farmers," said Sultan farmer Roger Finley, who watched the waters of the Skykomish River flood his fields and tear out his fences last year. "You can't incur the added expense and maintain profitability."

One solution, Kirschenmann said, is a national program geared toward restoring the health of the soil. Healthier soils mean less reliance on fertilizers and less need for water. Better soil would hold water longer, which would mean less erosion.

In the end, however, farmers will have to find better ways to diversify, including raising more than one crop and marketing more than one product, Kirschenmann said.

"There are unlimited possibilities for biological synergy," he said. "I think that would mean we'd have more farmers."

Christopher Schwarzen: 425-745-7813 or cschwarzen@seattletimes.com