Computed tomography scanning revealed macropore-controlled N 2 O emissions under long-term tillage and cover cropping practices.

Autor: Dhaliwal JK; Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA., Anderson SH; College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA., Lee J; Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA., Jagadamma S; Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA., Saha D; Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA. Electronic address: dsaha3@utk.edu.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 May 20; Vol. 926, pp. 171782. Date of Electronic Publication: 2024 Mar 22.
DOI: 10.1016/j.scitotenv.2024.171782
Abstrakt: Microscale alterations in soil physical characteristics resulting from long-term soil health practices can contribute to changes in soil nitrous oxide (N 2 O) emissions. In this study, we investigated soil N 2 O emissions in relation to pore characteristics influencing soil gas diffusivity under long-term tillage and cover cropping practices. Intact soil cores from tillage (conventional tillage, Conv. T versus no tillage, NT) and cover crop (hairy vetch, HV versus no cover crop, NC) treatments were used for N 2 O measurements and computed tomography (CT) scanning. Using X-ray CT technique with a resolution of 59 μm, pore structure parameters including macroporosity, number of macropores, anisotropy, fractal dimension, tortuosity, and connectivity were determined. The results showed that Conv. T and HV emitted significantly higher N 2 O than NT and NC, respectively. A similar trend was observed for macroporosity, Conv. T soils had 27.4 % higher CT-derived macroporosity than the NT soils and HV increased macroporosity by 31.1 % over the NC treatment. The number of macropores and fractal dimension were significantly higher whereas degree of anisotropy was significantly lower under HV compared to NC. In the upper 3 cm of soil, HV had a connected porosity, whereas the pores were disconnected and isolated in NC. These CT-derived properties; however, were not impacted by tillage treatments. N 2 O emissions were positively and significantly correlated to relative soil gas diffusivity, CT-derived macroporosity, number of macropores, and fractal dimension. Our results demonstrated that soil macroporosity and relative gas diffusivity could lead to improved understanding and predictability of N 2 O emissions under high soil moisture conditions.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: