Abstract
Soils are important sources and sinks of three greenhouse gases (GHGs): carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, it is unknown whether semiarid landscapes are important contributors to global fluxes of these gases, partly because our mechanistic understanding of soil GHG fluxes is largely derived from more humid ecosystems. We designed this study with the objective of identifying the important soil physical and biogeochemical controls on soil GHG fluxes in semiarid soils by observing seasonal changes in soil GHG fluxes across a three million year substrate age gradient in northern Arizona. We also manipulated soil nitrogen (N) and phosphorus availability with 7 years of fertilization and used regression tree analysis to identify drivers of unfertilized and fertilized soil GHG fluxes. Similar to humid ecosystems, soil N2O flux was correlated with changes in N and water availability and soil CO2 efflux was correlated with changes in water availability and temperature. Soil CH4 uptake was greatest in relatively colder and wetter soils. While fertilization had few direct effects on soil CH4 flux, soil nitrate was an important predictor of soil CH4 uptake in unfertilized soils and soil ammonium was an important predictor of soil CH4 uptake in fertilized soil. Like in humid ecosystems, N gas loss via nitrification or denitrification appears to increase with increases in N and water availability during ecosystem development. Our results suggest that, with some exceptions, the drivers of soil GHG fluxes in semiarid ecosystems are often similar to those observed in more humid ecosystems.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 375-391 |
| Number of pages | 17 |
| Journal | Biogeochemistry |
| Volume | 125 |
| Issue number | 3 |
| DOIs | |
| State | Published - Aug 25 2015 |
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Keywords
- Carbon dioxide
- Methane
- Nitrous oxide
- Nutrient addition
- Seasonality
- Substrate age gradient
ASJC Scopus subject areas
- Environmental Chemistry
- Water Science and Technology
- Earth-Surface Processes
Cite this
Proximate controls on semiarid soil greenhouse gas fluxes across 3 million years of soil development. / Sullivan, Benjamin W.; Nasto, Megan K.; Hart, Stephen C.; Hungate, Bruce A.
In: Biogeochemistry, Vol. 125, No. 3, 25.08.2015, p. 375-391.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Proximate controls on semiarid soil greenhouse gas fluxes across 3 million years of soil development
AU - Sullivan, Benjamin W.
AU - Nasto, Megan K.
AU - Hart, Stephen C.
AU - Hungate, Bruce A
PY - 2015/8/25
Y1 - 2015/8/25
N2 - Soils are important sources and sinks of three greenhouse gases (GHGs): carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, it is unknown whether semiarid landscapes are important contributors to global fluxes of these gases, partly because our mechanistic understanding of soil GHG fluxes is largely derived from more humid ecosystems. We designed this study with the objective of identifying the important soil physical and biogeochemical controls on soil GHG fluxes in semiarid soils by observing seasonal changes in soil GHG fluxes across a three million year substrate age gradient in northern Arizona. We also manipulated soil nitrogen (N) and phosphorus availability with 7 years of fertilization and used regression tree analysis to identify drivers of unfertilized and fertilized soil GHG fluxes. Similar to humid ecosystems, soil N2O flux was correlated with changes in N and water availability and soil CO2 efflux was correlated with changes in water availability and temperature. Soil CH4 uptake was greatest in relatively colder and wetter soils. While fertilization had few direct effects on soil CH4 flux, soil nitrate was an important predictor of soil CH4 uptake in unfertilized soils and soil ammonium was an important predictor of soil CH4 uptake in fertilized soil. Like in humid ecosystems, N gas loss via nitrification or denitrification appears to increase with increases in N and water availability during ecosystem development. Our results suggest that, with some exceptions, the drivers of soil GHG fluxes in semiarid ecosystems are often similar to those observed in more humid ecosystems.
AB - Soils are important sources and sinks of three greenhouse gases (GHGs): carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, it is unknown whether semiarid landscapes are important contributors to global fluxes of these gases, partly because our mechanistic understanding of soil GHG fluxes is largely derived from more humid ecosystems. We designed this study with the objective of identifying the important soil physical and biogeochemical controls on soil GHG fluxes in semiarid soils by observing seasonal changes in soil GHG fluxes across a three million year substrate age gradient in northern Arizona. We also manipulated soil nitrogen (N) and phosphorus availability with 7 years of fertilization and used regression tree analysis to identify drivers of unfertilized and fertilized soil GHG fluxes. Similar to humid ecosystems, soil N2O flux was correlated with changes in N and water availability and soil CO2 efflux was correlated with changes in water availability and temperature. Soil CH4 uptake was greatest in relatively colder and wetter soils. While fertilization had few direct effects on soil CH4 flux, soil nitrate was an important predictor of soil CH4 uptake in unfertilized soils and soil ammonium was an important predictor of soil CH4 uptake in fertilized soil. Like in humid ecosystems, N gas loss via nitrification or denitrification appears to increase with increases in N and water availability during ecosystem development. Our results suggest that, with some exceptions, the drivers of soil GHG fluxes in semiarid ecosystems are often similar to those observed in more humid ecosystems.
KW - Carbon dioxide
KW - Methane
KW - Nitrous oxide
KW - Nutrient addition
KW - Seasonality
KW - Substrate age gradient
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UR - http://www.scopus.com/inward/citedby.url?scp=84944168282&partnerID=8YFLogxK
U2 - 10.1007/s10533-015-0133-0
DO - 10.1007/s10533-015-0133-0
M3 - Article
VL - 125
SP - 375
EP - 391
JO - Biogeochemistry
JF - Biogeochemistry
SN - 0168-2563
IS - 3
ER -