What happens to organic matter when the soil is cultivated? Is it possible or necessary to maintain the high organic matter content of the soil at near-virgin levels to maintain crop years?
Anderson, Marvin and Ulrich, Rudolph
"Organic Matter- Where From Here?,"
Iowa Farm Science: Vol. 4
, Article 5.
Available at: https://lib.dr.iastate.edu/farmscience/vol4/iss5/5