Continued from last week:
Using a tool known as Soil Foodweb Analysis on the Menoken Farm, owned by the Burleigh County Soil Conservation District, Fuhrer showed total bacteria in the soil more than tripled from 2005 to 2010 and total fungi increased by about one-third. The soil was also initially low in beneficial nematode numbers, but cover crops quickly doubled them.
“There were not as many of those big guys in the soil to eat the little guys, which is not good for mineralization,” Furher says.
“In 2009, it was the first year we worked with the Menoken Farm, and we came out of a tillage environment into no-till.”
MIGHTY MICROBES. Those soil microbes rebuild damaged soil in ways scientists are just beginning to comprehend. New DNA analysis techniques show that as many as 50,000 types of bacteria exist in a relatively small soil sample.
“Many of these are new discoveries. We don’t know how they contribute to healthy soil structure or nitrogen content. We know a lot are decomposers. They break things down and liberate nitrogen. They’re critical for soil structure and keeping pathogens at bay. Can we promote a group that will have positive impacts for farming? We think these microorganisms can have big effects and that they take a long time to recover, once disturbed,” says Jay Lennon, Michigan State University professor of microbiology and molecular studies working at the W.K. Kellogg Biological Station at Hickory Corners, Mich.
Disturbing microbes with tillage turns the soil system on its head, say some scientists advocating conservation-tillage techniques.
“Tillage is like a wrecking ball that destroys soil aggregate structure,” says Kris Nichols, USDA Agriculture Research Service soil microbiologist at the Northern Great Plains Research Laboratory, Mandan, N.D. Nichols studies mycorrhizal fungi, tiny organisms with minute, threadlike fibers that hold soil “pellets” together-a critical part of structure.