As part of a $10 million effort funded by the U.S. Department of Agriculture's 's National Institute of Food and Agriculture, the first National Cover Crop Variety Test Report is being released publicly

One important benefit of cover crops to our production system is providing an alternative selection pressure on weed populations. Cereal rye has the best potential to suppress weeds because it accumulates more biomass than other cover crop species. Read more in this article from Iowa State University Extension.

A study found that legume covers actually supplied little total nitrogen due to low biomass production, while the nitrogen contained in cereal rye residue was likely readily available for the next corn crop.