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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGING FARMS FOR ENVIRONMENTAL STEWARDSHIP AND PROFIT

Location: Pasture Systems & Watershed Management Research

Title: Nitrous oxide emissions with enhanced efficiency nitrogen fertilizers in rainfed system

Authors
item DELL, CURTIS
item Han, Kun -
item BRYANT, RAY
item Schmidt, John -

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2013
Publication Date: March 6, 2014
Citation: Dell, C.J., Han, K., Bryant, R.B., Schmidt, J.P. 2014. Nitrous oxide emissions with enhanced efficiency nitrogen fertilizers in rainfed system. Agronomy Journal. 106:723-731.

Interpretive Summary: The use of enhanced efficiency nitrogen (N) fertilizers (e.g., slow release fertilizers) can increase crop N utilization and lead to lower emissions of the greenhouse gas nitrous oxide (N2O). To determine potential benefit of four enhanced efficiency fertilizers with rain-fed corn production in central Pennsylvania, USA, N2O emissions and grain yield were monitored during a four year field study and compared to those with untreated urea prills and urea ammonium nitrate (UAN). The tested enhanced efficiency products were Environmentally Safe Nitrogen (ESN), which is a polymer coated urea, SuperU, which contains urease and nitrification inhibitors, UAN treated with AgrotainPlus, which is a urease and a nitrification inhibitor, and Plant impact Nitrogen Technology (PiNT-Ca), which is a calcium cation stabilized amine-N. Extended dry periods limited denitrification potential and overall N2O emissions in the field. Although spikes of N2O emission were seen within one month after fertilizer application in each year, cumulative growing season N2O emissions and grain yield were similar for all N sources in each year of the study. Enhanced efficiency fertilizers do not appear to be an effective means to reduce N2O emission in a rain-fed system, at least when rainfall is inconsistent.

Technical Abstract: The use of enhanced efficiency nitrogen (N) fertilizers can increase crop N utilization and lead to lower emissions of the greenhouse gas nitrous oxide (N2O). To determine potential benefit of four enhanced efficiency fertilizers with rain-fed corn production in central Pennsylvania, USA, N2O emissions and grain yield were monitored during a four year field study and compared to those with untreated urea prills and urea ammonium nitrate (UAN). The tested enhanced efficiency products were ESN (polymer coated urea), SuperU (urease and nitrification inhibitor treated urea), UAN treated with AgrotainPlus (urease and nitrification inhibitor), and PiNT (cation stabilized amine-N). Additionally, 28-day laboratory incubations were conducted to verify the potential differences in N cycling rates among N sources. The laboratory incubations indicated that ESN, SuperU, and treated UAN all had the potential to delay accumulation of nitrate relative to untreated urea and UAN, but N cycling was similar with PiNT and the untreated fertilizers. Extended dry periods limited denitrification potential and overall N2O emissions in the field, but spikes of N2O emission were seen within one month after fertilizer application in each year. However, variation in emission rates was high within treatments and no consistent differences among N sources were seen. Cumulative growing season N2O emissions and grain yield were similar for all N sources in each year of the study. Enhanced efficiency fertilizers do not appear to be an effective means to reduce N2O emission in a rain-fed system, at least when rainfall is inconsistent.

Last Modified: 9/10/2014
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