Review of Nitrogen and Phosphorus Fertilizer Efficiency Research.

Nitrogen (N) and phosphorus (P) fertilization is essential for sustaining life on Earth. Inherent inefficiencies in cycling of these nutrients results in nutrient pollution. Nitrate-N readily leaches to groundwater, which at high concentration is a health hazard. Runoff of N and P to surface water results in eutrophication. Significant quantities of ammonia (reactive atmospheric N) and nitrous oxide (potent greenhouse gas) are lost to the atmosphere. Additionally, loss of these nutrients to the environment represents waste for growers and natural resources. Therefore, significant efforts to improve nutrient use efficiency have been undertaken. Various new fertilizer products have been developed to improve nutrient use efficiency. These products have been engineered to improve timing of nutrient release or attempt to sequester the nutrient from interfering ions or, in the case of P, improve solubility. In addition to new products, research on timing, rate, and placement of these nutrients has proven to improve nutrient use efficiency. Examples of success (and failures) of each of these approaches to improving N and P use efficiency will be highlighted in this presentation. For example, one N fertilizer product shows ability to improve N use efficiency by up to 35%. In another example, P use efficiency increased by 50%.