It has long been suspected that root hydraulic redistribution (HR) affects the carbon and nitrogen cycles. Nitrous oxide (N2O) is an important greenhouse gas and is the primary stratospheric ozone-depleting substance. To our knowledge, the influences of HR on N2O emissions have not been investigated. Here we use the HR schemes of Ryel et al. and Amenu and Kumar incorporated into CLM4.5 to examine N2O emissions at five AmeriFlux sites. The results show that HR reduced N2O emissions by 28–92% in the four natural ecosystems experiencing a dry season, whereas it had a very limited effect on the Corn Belt site that has strong emissions but with no distinct dry season. We hypothesize that N2O emissions in ecosystems with a distinct dry season are likely overestimated by CENTURY-based Earth system models.
Bibliographical noteFunding Information:
This study was funded by grants sup ported by the U.S. Department of Agriculture grant USDA-NIFA 2013- 67019-21364 and the Pioneer Hundred Talent Program, Chinese Academy of Sciences (Y7BR021001). We thank Zoe G. Cardon, Kenneth Bible, Michael L. Goulden, Scott R. Saleska, and Russell L. Scott for providing suggestions and data. Atmospheric forcing, ET, and NEE data for the US-Ro1 site are available at ftp://ftp.fluxdata.org/.ameriflux_downloads/, and N2O emission and soil moisture data for this site are available at http://www.biometeorology.umn. edu/research/data-archives and http:// cosmos.hwr.arizona.edu/Probes/ StationDat/041/index.php, respectively. Atmospheric forcing, soil moisture, ET, and NEE data for US-SCf and other three terrestrial sites are hosted at http:// www.ess.uci.edu/~california/ and https://daac.ornl.gov/get_data/, respectively.
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- AmeriFlux site
- Corn Belt
- dry season
- nitrous oxide
- root hydraulic redistribution