Atmospheric Emissions of Nitrous Oxide, Methane, and Carbon Dioxide from Different Nitrogen Fertilizers

Abstract

Alternative N fertilizers that produce low greenhouse gas (GHG) emissions from soil are needed to reduce the impacts of agricultural practices on global warming potential (GWP). We quantified and compared growing season fluxes of NO, CH, and CO resulting from applications of different N fertilizer sources, urea (U), urea-ammonium nitrate (UAN), ammonium nitrate (NHNO), poultry litter, and commercially available, enhanced-efficiency N fertilizers as follows: polymer-coated urea (ESN), SuperU, UAN + AgrotainPlus, and poultry litter + AgrotainPlus in a no-till corn ( L.) production system. Greenhouse gas fluxes were measured during two growing seasons using static, vented chambers. The ESN delayed the NO flux peak by 3 to 4 wk compared with other N sources. No significant differences were observed in NO emissions among the enhanced-efficiency and traditional inorganic N sources, except for ESN in 2009. Cumulative growing season NO emission from poultry litter was significantly greater than from inorganic N sources. The NO loss (2-yr average) as a percentage of N applied ranged from 0.69% for SuperU to 4.5% for poultry litter. The CH-C and CO-C emissions were impacted by environmental factors, such as temperature and moisture, more than the N source. There was no significant difference in corn yield among all N sources in both years. Site specifics and climate conditions may be responsible for the differences among the results of this study and some of the previously published studies. Our results demonstrate that N fertilizer source and climate conditions need consideration when selecting N sources to reduce GHG emissions.

In-Field Management Practices for Mitigating Soil CO<sub>2</sub> and CH<sub>4</sub> Fluxes under Corn (<i>Zea mays</i>) Production System in Middle Tennessee

“…Our results demonstrated that the soils in our cornfields were a net sink for CH 4 (Figure 2(d)). The generally low values and net uptake of CH 4 presented in our study were consistent with those reported for other cornfields [7] [14] [21].…”

“…In addition, we found that improved fertilizer and soil management significantly affected soil moisture sensitivity (c value) of soil CH 4 flux ( Table 3). This indicated that increasing soil moisture has potential to result in a significant change in soil CH 4 flux among the treatments. The result reported here supported our hypothesis, and might help explain the contradicting results of previous studies that the effects of agricultural practices on soil CH 4 flux depend on the levels of soil moisture at the study sites [7] …”

“…Historically, agriculture soils have lost more than 50 Pg C, mostly in the form of CO 2 emitting back into the atmosphere [3]. The issue of how to reduce soil C emissions in croplands while maintaining high crop yields has become an important task [4] [5]. In recent years many agricultural practices, such as no-tillage, alternative use of fertilizer sources or methods (e.g., manure, split applications), and soil management (e.g., use of denitrification inhibitor or biochar), have been proposed as effective ways to enhance crop production and hence sequester atmospheric CO 2 in soils [6].…”

“…For instance, no-tillage reduces CH 4 emissions from paddy soils because soil conditions under no-tillage are more oxidative than those of conventional tillage [19] [20]. Applications of swine manure in a continuous corn cropping system result in net CH 4 emission, whereas similar plots receiving urea fertilizer are sinks of CH 4 in the eastern United States [21]. Similarly, biochar applications were reported to decrease emissions of CH 4 in many croplands [18].…”

Nitrous Oxide Emissions from a Clay Soil Receiving Granular Urea Formulations and Dairy Manure

“…Li et al (2012) recently showed that polymer-coated urea reduced N 2 O emissions compared with conventional urea. Other studies, however, found more N 2 O emissions from polymer-coated than from conventional urea (Sistani et al, 2011;Jiang et al, 2010;Zebarth et al, 2012) and that the effectiveness of stabilizers varied with soil properties (Kelliher et al, 2008), highlighting uncertainty in the effectiveness of enhanced-efficiency N fertilizer products to mitigate emissions. Nitrate intensity, sometimes referred as nitrate exposure, was introduced by Zebarth et al (2008aZebarth et al ( , 2008b and Burton et al (2008aBurton et al ( , 2008b as an assessment of the magnitude and duration of soil NO 3 -and its potential impact on soil biology and the potential for NO 3 -loss to the environment.…”