Defining 4R Phosphorus Practices to Contribute to Continental Improvement of Water Quality.

The driving forces of the sustainable agriculture movement require expert advisors and stakeholder input to prioritize efforts that improve the environmental performance, or outcomes, of agricultural systems. To usefully identify and address synergies and trade-offs among the economic, social and environmental impacts of crop production, such input must be informed by clear understanding of the connection between practices and outcomes. 4R Nutrient Stewardship seeks to educate a broader audience about the science linking crop nutrient management practices to nutrient loss. With support from a broad range of stakeholders, the impact of efforts by technical experts, crop advisers and producers can be enhanced and more widely communicated. Additionally, the broadening agriculture stakeholder group can be utilized to increase attention to identified research and knowledge gaps which must be addressed to fulfill the needs of the sustainability movement. At a workshop of scientists recognized for their expertise in agricultural phosphorus loss reduction, three levels of practices were defined that could be recognized as having value in limiting losses from a range of cropping systems and regions. This presentation aims to describe these practices and knowledge gaps.