LIND, Wash. — When Shannon Cappellazzi speaks of tornadoes, she’s not referring to funnel clouds and high winds.
As the lead scientist for the western U.S. at the nonprofit Soil Health Institute, Cappellazzi is most concerned with what happens beneath the surface of the soil.
A major concern for her is tillage and how it impacts microbes.
“If you were to imagine a tornado coming through your community once a year, two times a year, six times a year, what would happen? What would you do after that tornado came through each time?” she asked. Microbes, she said, “might only have energy to try to rebuild their structures so they can start to do their work again.”
Cappellazzi, based at Oregon State University in Corvallis, is part of a project that is sampling the soil at 120 sites around North America. The sites have had the same management for at least a decade and some up to 150 years.
Cappellazzi defined soil health as the continued capacity to function as a vital ecosystem.
Soil holds, stores and delivers water; cycles nutrients; and provides food, water, air and shelter for the microbes in the soil.
The focus on soil function reduces farmers’ input costs, including fertilizer and chemical pesticides, Cappellazzi said.
“We want the soil to function so you don’t have to do as many functions,” she told growers June 13 during the Lind Field Day at Washington State University’s dryland research station.
Increasing crop diversity or adding animals into the rotation can improve soil cycles, she said.
“When we have more above-ground diversity, we tend to see more below-ground diversity,” Cappellazzi said.
Compost, manure or biosolids give the microbes needed carbon to increase organic matter, which leads to more water-holding capacity.
The institute compares soils using about 30 soil health indicators.
“We want to know what are the tests we need in order for you to be able to make a decision about how well your soil is cycling nutrients,” Cappellazzi said.
Researchers want to use the indicators to assess whether farm management practices are enhancing soil functions.
Wheat is the best-represented crop in the project, Cappellazzi said. It is included in about 60 of the 120 sites, some as a cover crop.
She compared pictures of soil at various sites in the Pacific Northwest, from a no-till farming site to a site that’s consistently burned wheat stubble for 40 years and a grassland site with no agricultural production.
“We need to make sure when we send these three soils to a lab ... we know how to interpret them,” she said.