Nutrient Management on Irrigated Farms in Colorado: Factors Affecting the Adoption of Best Management Practices.

Irrigated farming in Colorado covers more than 1.2 million hectares, and is a valuable part of the state’s economy and way of life. Successful crop and livestock production in these systems requires the addition of supplemental nutrients, especially nitrogen and phosphorus. Environmental losses of nutrients can lead to eutrophication of water bodies and degraded water quality. Nitrate above the USEPA drinking water standard (10 mg L^-1 NO₃–N) in groundwater is consistently found in some parts of Colorado. Long term efforts to reduce the impact of agriculture on Colorado surface and groundwater have involved ongoing development and promotion of Best Management Practices (BMPs). In order to accurately characterize BMP adoption in Colorado, data about nutrient management practices and associated costs were documented in 2011. Data was collected using a mailed survey sent to 2000 farmers with at least 40.5 hectares under irrigated production After the exclusion of individuals who had left farming, had less than 40.5 hectares or do not irrigate, the final response usable response rate was 37%. The survey was designed to collect information to complement similar surveys done 1997 and 2001. The fundamental finding of the study was that most respondents are voluntarily implementing some level of nutrient BMPs. In general, lower cost BMPs had higher rates of adoption, and the more expensive practices may require incentive programs to increase farmer implementation. Further analysis compares BMP adoption rates of alfalfa, corn, and other high value crop growers (defined as those with at least 60% of production acres in a particular crop category) in 2001 and 2011. Lower rates of BMP adoption with manure use versus chemical fertilizer use, impact of county level animal density, farmer demographics and other factors are presented.