The 4R philosophy is an innovative and science-based approach that offers enhanced environmental protection, increased production, increased farmer profitability, and improved sustainability. The concept is to use the right fertilizer source, at the right rate, at the right time, with the right placement. Implications of the 4R nutrient stewardship system will spread far and wide through agriculture and society as a whole. For fertilizer use to be sustainable, it must support cropping systems that provide economic, social, and environmental benefits. Enhanced understanding, adoption and promotion of 4R stewardship is the goal of the sponsors of this website.