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In potentially “the most important agricultural study this year,” researchers find that sustainable farming methods can help conventional agriculture “shed much of its chemical use,” according to New York Times writer and food author Mark Bittman.

The Marsden Farm study, conducted by a team of government and university researchers, is a large-scale, long-term experiment that took place over the course of nine years (2003-2011) on land owned by Iowa State University. On 22 acres, researchers planted three parallel plots: one replicating the conventional Midwestern farming cycle alternating corn and soybeans each year with a routine mix of chemicals; in the second, planting a three-year cycle that included oats and a red clover cover crop; the third was planted on a 4-year rotation that added alfalfa (a key livestock feed). The two longer rotations also integrated the use of manure, or livestock fertilizer.

Researchers compared the systems on productivity, profitability, and environmental health and the findings-published earlier this month in the journal PLOS One-according to Bittman, “are stunning:”

 The longer rotations produced better yields of both corn and soy, reduced the need for nitrogen fertilizer and herbicides by up to 88 percent, reduced the amounts of toxins in groundwater 200-fold and didn’t reduce profits by a single cent.

“These were simple changes patterned after those used by North American farmers for generations,” said Adam Davis, an author of the study who works for the U.S.D.A. “What we found was that if you don’t hold the natural forces back they are going to work for you.”

Bittman, summarizing the report’s abstract, writes: “So: combine crop rotation, the re-integration of animals into crop production and intelligent farming, and you can use chemicals to fine-tune rather than drive the system, with no loss in performance and in fact the gain of animal products.”

The study observed that these more sustainable methods are more labor intensive: increased crop rotation, mulching, the reintegration of animals, more exposure and knowledge of the fields, more observations, etc. Davis adds, “you substitute producer knowledge for blindly using inputs.”