Beginning in 2003, researchers planted three plots: one replicating the conventional method of planting corn one year and soybeans the next, adding a routine mix of fertilizing chemicals; another using a three-year cycle that included planting oats; and one using a four-year cycle and planting alfalfa, along with integration of raising livestock, manure from which was used as fertilizer.
Not only did the longer rotations produce better crops, they also "reduced the need for nitrogen fertilizer and herbicides by up to 88 percent, reduced the amount of toxins in groundwater 200-fold and didn't reduce profits by a single cent," Mark Bittman of The New York Times writes. "In short, there was only upside -- and no downside at all -- associated with the longer rotations," he continues. There was an increase in labor costs, but Bittman counters that profits remained stable.
Bittman does not address the question of scalability, whether these methods could be adopted on mass scale, and where the labor would come from. He hints at those questions by writing, "Perhaps most difficult to quantify is that this kind of farming — more thoughtful and less reflexive — requires more walking of the fields, more observations, more applications of fertilizer and chemicals if, when and where they’re needed, rather than on an all-inclusive schedule." (Read more)