title: A geostatistical approach to identify and mitigate agricultural nitrous oxide emission hotspots.
abstract: Anthropogenic emissions of nitrous oxide (N2O), a trace gas with severe environmental costs, are greatest from agricultural soils amended with nitrogen (N) fertilizer. However, accurate N2O emission estimates at fine spatial scales are made difficult by their high variability, which represents a critical challenge for the management of N2O emissions. Here, static chamber measurements (n=60) and soil samples (n=129) were collected at approximately weekly intervals (n=6) for 42-d immediately following the application of N in a southern Minnesota cornfield (15.6-ha), typical of the systems prevalent throughout the U.S. Corn Belt. These data were integrated into a geostatistical model that resolved N2O emissions at a high spatial resolution (1-m). Field-scale N2O emissions exhibited a high degree of spatial variability, and were partitioned into three classes of emission strength: hotspots, intermediate, and coldspots. Rates of emission from hotspots were 2-fold greater than non-hotspot locations. Consequently, 36% of the field-scale emissions could be attributed to hotspots, despite representing only 21% of the total field area. Variations in elevation caused hotspots to develop in predictable locations, which were prone to nutrient and moisture accumulation caused by terrain focusing. Because these features are relatively static, our data and analyses indicate that targeted management of hotspots could efficiently reduce field-scale emissions by as much 17%, a significant benefit considering the deleterious effects of atmospheric N2O.
authors.affiliation: Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA. Electronic address: turne289@umn.edu.
authors.forename: P A
authors.initials: PA
authors.lastname: Turner
authors.affiliation: Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Griffis
authors.affiliation: Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Mulla
authors.affiliation: Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA; United States Department of Agriculture - Agricultural Research Service, Soil and Water Management Unit, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Baker
authors.affiliation: Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA; United States Department of Agriculture - Agricultural Research Service, Soil and Water Management Unit, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Venterea
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D018556:Crops, Agricultural / Q000378:metabolism*; D004784:Environmental Monitoring / Q000379:methods*; D008910:Minnesota; D008962:Models, Theoretical; D009609:Nitrous Oxide / Q000032:analysis*; D003313:Zea mays / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D009609:Nitrous Oxide
keywords: Biogeochemical hotspots; Geospatial cokriging; Greenhouse gas management; LiDAR digital elevation model; Nitrous oxide