Overview of Current and Future Agricultural and Environmental Need for Enhanced Efficiency Fertilizers.
Paul Fixen, Potash & Phosphate Institute, 772-22nd Ave. S, Brookings, SD 57006
The need for improving fertilizer use efficiency is usually perceived to be greatest for nitrogen (N) fertilizers due the transient nature of N in soils. Though N use efficiency has been steadily climbing in many regions, N fertilizer recovery efficiencies for the year of application in today’s major cereal cropping systems have been estimated to often be less than 50% in farm fields. Nitrogen not recovered by the crop in the first year may not necessarily be lost, but it is clearly at elevated risk for loss and the delayed agronomic benefit reduces its economic value. As energy and fertilizer prices climb, the value of lost N also increases, justifying additional investment in loss prevention. Potential negative environmental impacts of N lost from agroecosystems are numerous and can be complex. Potential impacts include surface water eutrophication, acidification, loss of biodiversity, stratospheric ozone depletion, respiratory problems associated with particulate matter, and greenhouse gas formation. Society will continue to expect agriculture to reduce nutrient losses that can potentially contribute to these problems. Society will also expect agricultural productivity (food, feed, fiber, and fuel) to increase, and as entrepreneurs, we should also desire to increase productivity. Global fertilizer N use in 2004/2005 was about 90 million tones and is projected to increase to between 107 and 171 million tonnes by 2050. The range in projected use is caused primarily by the assumptions made concerning the magnitude of N losses from farm fields. More efficient fertilizers that better synchronize N release and crop N demand would be a great asset to crop producers as they strive to reduce N losses while increasing productivity. However, they will only be effective if used in a system that recognizes the impact of enhanced efficiency fertilizers on rate, placement, and timing decisions.