Uncertainties in the Current Knowledge of Some Atmospheric Trace Gases Associated with U.S. Agriculture: A Review

Abstract

Approximately 80 different crop species are grown in the United States in widely differing geographic areas, climatic and edaphic conditions, and management practices. Although the majority of cultivated acreage in the United States is planted with only about 10 primary crops, uncertainties associated with trace gas emissions arise from: (1) limited data availability, (2) inaccurate estimates because of large temporal and spatial variability in trace gas composition and magnitude of trace gas emissions from agricultural activities, (3) differing characteristics of pollutant emissions from highly dispersed animal feed-lots, and (4) limited understanding of the emissions of semi-volatile organic compounds (SVOCs) associated with agriculture. Although emission issues are of concern, so also is atmospheric deposition to cropping systems, including wet and dry nitrogen, minerals, and organic compounds. These can have feedback effects on trace gas emissions. Overall, the many gaps in our understanding of these aspects of agricultural systems deserve serious attention.

Interannual variability in soil nitric oxide emissions over the United States as viewed from space

“…Surface observations of S NO x at the spatial scales needed to observe and infer mechanistic details affecting the emissions have sparse spatial coverage, so generalizing these results to regional and global budgets has proven difficult (e.g., Krupa et al, 2008;Ludwig et al, 2001;Conrad et al, 1996). To bridge the gap between global analyses that identify a need for enhanced emissions at regional scales (100 s of km) and observations that can define processes affecting NO x at meter scales, Bertram et al (2005) used daily NO 2 columns retrieved from SCIAMACHY at 30 km × 60 km to explore S NO x following N-fertilization to dry agricultural fields.…”

Interannual variability in soil nitric oxide emissions over the United States as viewed from space

“…Surface observations of S NO x at the spatial scales needed to observe and infer mechanistic details affecting the emissions have sparse spatial coverage, so generalizing these results to regional and global budgets has proven difficult (e.g., Krupa et al, 2008;Ludwig et al, 2001;Conrad et al, 1996). To bridge the gap between global analyses that identify a need for enhanced emissions at regional scales (100 s of km) and observations that can define processes affecting NO x at meter scales, Bertram et al (2005) used daily NO 2 columns retrieved from SCIAMACHY at 30 km × 60 km to explore S NO x following N-fertilization to dry agricultural fields.…”

Plants and Atmospheric Aerosols

“…Uptake into plants may occur through roots, particularly of low molecular weight organic compounds, as a function of aqueous solubility (Krupa et al 2008) and mostly at the air-plant interface (Tao et al 2006). Plant cuticles are composed of waxy materials in which lipophilic organic aerosol may embed or dissolve.…”