Michigan State University2014-07-03 6:00 PM

Global metaanalysis of the nonlinear response of soil nitrous oxide (N2O) emissions to fertilizer nitrogen

Abstract
Nitrous oxide (N2O) is a potent greenhouse gas (GHG) that also depletes stratospheric ozone. Nitrogen (N) fertilizer rate is the best single predictor of N2O emissions from agricultural soils, which are responsible for ∼50% of the total global anthropogenic flux, but it is a relatively imprecise estimator. Accumulating evidence suggests that the emission response to increasing N input is exponential rather than linear, as assumed by Intergovernmental Panel on Climate Change methodologies. We performed a metaanalysis to test the generalizability of this pattern. From 78 published studies (233 site-years) with at least three N-input levels, we calculated N2O emission factors (EFs) for each nonzero input level as a percentage of N input converted to N2O emissions. We found that the N2O response to N inputs grew significantly faster than linear for synthetic fertilizers and for most crop types. N-fixing crops had a higher rate of change in EF (ΔEF) than others. A higher ΔEF was also evident in soils with carbon >1.5% and soils with pH <7, and where fertilizer was applied only once annually. Our results suggest a general trend of exponentially increasing N2O emissions as N inputs increase to exceed crop needs. Use of this knowledge in GHG inventories should improve assessments of fertilizer-derived N2O emissions, help address disparities in the global N2O budget, and refine the accuracy of N2O mitigation protocols. In low-input systems typical of sub-Saharan Africa, for example, modest N additions will have little impact on estimated N2O emissions, whereas equivalent additions (or reductions) in excessively fertilized systems will have a disproportionately major impact.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

Michigan State University

0 Following 0 Fans 0 Projects 13 Articles

SIMILAR ARTICLES

AbstractStudies regarding the advancing challenges of obesity in many countries are beginning to converge on the importance of early food exposure and

Read More

Genomic variability limits the efficacy of breast cancer therapy. To simplify the study of the molecular complexity of breast cancer, researchers have

Read More

AbstractNitrous oxide (N2O) is a potent greenhouse gas (GHG) that also depletes stratospheric ozone. Nitrogen (N) fertilizer rate is the best single pr

Read More

ABSTRACTLittle is known about the genetic basis of convergent traits that originate repeatedly over broad taxonomic scales. The myogenic electric organ

Read More

ABSTRACTLittle is known about the genetic basis of convergent traits that originate repeatedly over broad taxonomic scales. The myogenic electric organ

Read More

AbstractThe use of laptops and cell phones in the classroom is increasing but there is little research assessing whether these devices create distracti

Read More

AbstractPatterns of flows of cocaine across the United States are identified using open-source price data. The data set consists of wholesale prices fo

Read More

AbstractTheories of skilled performance that emphasize training history, such as K. Anders Ericsson and colleagues’ deliberate-practice theory, have re

Read More

AbstractThere has been a steady increase in security guard employment in the United States in recent decades. Data estimates for 2010 suggest that ther

Read More

AbstractThis article considers the impact of a high-stakes testing and reporting requirement on students using publicly funded vouchers to attend priva

Read More