Improving conservation practices programming to protect water quality in agricultural watersheds: Lessons learned from the National Institute of Food and Agriculture–Conservation Effects Assessment Project

Excerpt

Nutrient enrichment and sedimentation of water resources is a significant problem in the United States and globally (Carpenter et al. 2011; Dubrovsky et al. 2010; Hilton et al. 2006). Specifically, in the United States, over 6,908 water bodies are listed as being nutrient impaired and 6,165 are sediment impaired (USEPA 2012). Agricultural nonpoint source pollution contributes, in part, to impaired water resources in many of these watersheds (NRC 2008; USEPA 2010).

Conservation practices, including conservation tillage, nutrient management, and riparian buffers, are routinely used to reduce off-site losses of sediment, nutrients, pesticides, and bacteria from agricultural operations. Many research studies, generally conducted at the plot- or field-scale, report ranges in effectiveness of such conservation practices, from being negative to 100% effective (Gagnon et al. 2004; Gagnon et al. 2008; Jokela et al. 2004; Line et al. 2001; Richards and Baker 2002; Schnepf and Cox 2006; Sharpley et al. 2006; Shepard 2005; Smith et al. 2006).

Documentation of combined practice impacts on water quality at the watershed scale has been more difficult than in plot or field-scale studies. The Black Creek Project in northeastern Indiana and the Model Implementation Program (MIP) promoted by the USDA and US Environmental Protection Agency (USEPA)…