New Developments in Fertilizer Technology.

High fertilizer costs and concerns about environmental impacts of crop nutrients have sparked much interest in improving nutrient-use efficiency.  Proper nutrient management should follow a “4R” approach: apply the right source at the right rate, right time, and in the right place with regard for agronomic, economic, environmental, and social outcomes.  While basic fertilizer chemistry and materials have changed little over the years, there are fertilizer materials and delivery systems currently available that can improve agronomic efficiency and reduce environmental impacts of applied nutrients.  These fertilizer materials have come to be known as “enhanced-efficiency fertilizers”.  Many of the enhanced-efficiency fertilizers have proven to improve nutrient-use efficiency, reduce losses, and simplify nutrient management in turf, horticulture, and specialty crop production for years.  They have been less widely used in broad-acre agricultural crops because of high cost and low crop value, but recent technological advances, higher N costs, and concerns about environmental impacts of nutrients have increased the interest in new fertilizer technologies and agricultural adaptation of enhanced-efficiency fertilizers. Most past advances in nutrient-delivery technologies have focused on modifications or adaptations of existing chemistry or delivery systems.  Significant further advances may require completely rethinking our approaches to nutrient delivery.  New technologies may involve more natural materials, less dependence on petroleum derivatives, new chemistries, and more specific means of nutrient delivery.  Current and future approaches will be explored.