Pathways for Nitrous Oxide Generation in Forested and Agricultural Zones Growing on Volcanic Ash Soils
- PDF / 1,392,910 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 111 Downloads / 194 Views
ORIGINAL PAPER
Pathways for Nitrous Oxide Generation in Forested and Agricultural Zones Growing on Volcanic Ash Soils Jaime G. Cuevas 1,2,3 & Leandro Paulino 2,4 & José Dörner 2,5 Received: 12 December 2019 / Accepted: 29 April 2020 # Sociedad Chilena de la Ciencia del Suelo 2020
Abstract We studied the in situ relative contribution of soil nitrous oxide (N2O) emissions from already discovered pathways, namely the nitrification, nitrifier denitrification (ND), and heterotrophic denitrification (HD). We selected a transect from upland pastures to lowland riparian forests growing on volcanic ash soils. We used the acetylene blocking technique, and N2O was measured by gas chromatography. We also measured rates of potential organic matter mineralization and potential nitrification in laboratory. Potential mineralization increased from uplands to lowlands, while potential nitrification decreased in the same transect. In riparian forests, N2O emissions under acetylene blocking were higher than without acetylene, revealing that 22–31% of nitrogen emissions consisted of dinitrogen. Conversely, in pastures, N2O emissions under acetylene blocking were lower than without acetylene. Our results suggest that HD predominates in waterlogged, anoxic, and acidic soils with no nitrification, which are typical conditions for riparian soils. Conversely, N2O from nitrification and ND predominates in more oxic environments that are less water-saturated, have less acidic soils, and a larger nitrification rate than riparian areas (i.e., typical conditions for pasture soils). Thus, processes related to the nitrogen cycle depend on the land cover/use and soil physical-chemical properties, even in vegetation zones growing on adjacent soil types. Our results imply that different mitigation measures must be implemented to abate N2O emissions in different soil environments. Keywords Andisols . Denitrification . Potential mineralization . Potential nitrification . Nitrogen cycle
1 Introduction Nitrous oxide (N2O) is a greenhouse effect gas with about 310 times the global warming potential of an equivalent amount of carbon dioxide (Wrage et al. 2001). This gas is also involved in stratospheric ozone destruction (Crutzen 1970). The
* Jaime G. Cuevas [email protected] 1
Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Av. Raúl Bitrán, 1305 La Serena, Chile
2
Centro de Investigación en Suelos Volcánicos (CISVo), Universidad Austral de Chile, Valdivia, Chile
3
Instituto de Ecología y Biodiversidad (IEB), Santiago, Chile
4
Departamento de Suelos y Recursos Naturales, Facultad de Agronomía, Universidad de Concepción, Casilla, 537 Chillán, Chile
5
Facultad de Ciencias Agrarias y Alimentarias, Instituto de Ingeniería Agraria y Suelos, Universidad Austral de Chile, Casilla, 567 Valdivia, Chile
classical model for N2O production established that denitrification (DN) begins when nitrate (NO3−) is converted into nitrite (NO2−); then, NO2− is transformed in nitric oxide (NO), then into N2O, and finally in dinitrogen (N2) (Fig. 1c) (Stevens
Data Loading...
