“But we already know that cover crops can typically reduce nitrogen fertilizer pollution by 40 to 70 percent, reduce the need for pesticides and fertilizers, enrich the soil, and maintain or increase crop productivity. Cover crops are not widely used today due to misplaced policies like insurance penalties, and lack of research and infrastructure to make them more farmer-friendly. Other ecologically based farming methods can provide similar benefits.
”Gurian-Sherman, D. 2012. "A less thirsty future through engineered crops?" Union of Concerned Scientists, Sept 13, 2012. http://blog.ucsusa.org/a-less-thirsty-future-through-engineered-crops/?u...
SOURCE for "cover crops can typically reduce nitrogen fertilizer pollution by 40 to 70 percent":Tonitto, C. et al. 2006. "Replacing bare fallows with cover crops in fertilizer-intensive cropping systems: A meta-analysis of crop yield and N dynamics." Agriculture, Ecosystems and Environment, 112: 58-72. http://www.sciencedirect.com/science/article/pii/S0167880905003749
SOURCE for "similar benefits":Liebman, M. et al. 2008. "Agronomic and Economic Performance Characteristics of Conventional and Low-External-Input Cropping Systems in the Central Corn Belt." Agronomy Journal. 100(3): 600-610. https://www.soils.org/publications/aj/articles/100/3/600