absorption
; agricultural soil
; anthropogenic source
; denitrification
; greenhouse gas
; moisture content
; nitrogen dioxide
; plant residue
; pore space
; soil emission
; water
英文摘要:
N 2 O is a highly potent greenhouse gas and arable soils represent its major anthropogenic source. Field-scale assessments and predictions of soil N 2 O emission remain uncertain and imprecise due to the episodic and microscale nature of microbial N 2 O production, most of which occurs within very small discrete soil volumes. Such hotspots of N 2 O production are often associated with decomposing plant residue. Here we quantify physical and hydrological soil characteristics that lead to strikingly accelerated N 2 O emissions in plant residue-induced hotspots. Results reveal a mechanism for microscale N 2 O emissions: water absorption by plant residue that creates unique micro-environmental conditions, markedly different from those of the bulk soil. Moisture levels within plant residue exceeded those of bulk soil by 4-10-fold and led to accelerated N 2 O production via microbial denitrification. The presence of large (" >35 μm) pores was a prerequisite for maximized hotspot N 2 O production and for subsequent diffusion to the atmosphere. Understanding and modelling hotspot microscale physical and hydrologic characteristics is a promising route to predict N 2 O emissions and thus to develop effective mitigation strategies and estimate global fluxes in a changing environment.
Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States; Department of Integrative Biology and DOE Great Lakes Bioenergy Research Institute, Michigan State University, East Lansing, MI, United States; Faculty of Resources and Environmental Science, Hubei University, Wuhan, China; Department of Agronomy, University of Agriculture, Peshawar, Khyber Pakhtunkhwa, Pakistan; Center for Advanced Radiation Sources, University of Chicago, Argonne National Lab, Argonne, IL, United States; W. K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI, United States
Recommended Citation:
Kravchenko A.N.,Toosi E.R.,Guber A.K.,et al. Hotspots of soil N 2 O emission enhanced through water absorption by plant residue[J]. Nature Geoscience,2017-01-01,10(7)