{18DA5C01-F53D-4CC3-B557-046C3FF5A584} eng; USA utf8 dataset EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact 2025-07-23 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) EnviroAtlas - Cultivated biological nitrogen fixation in agricultural lands by 12-digit HUC in the Conterminous United States, 2006 2015-05-07 publication U.S. EPA Office of Research & Development (ORD) - National Exposure Research Laboratory (NERL) Research Triangle Park NC publisher US Environmental Protection Agency (US EPA) originator This EnviroAtlas dataset contains data on the mean cultivated biological nitrogen fixation (C-BNF) in cultivated crop and hay/pasture lands per 12-digit Hydrologic Unit (HUC) in 2006. Nitrogen (N) inputs from the cultivation of legumes, which possess a symbiotic relationship with N-fixing bacteria, were calculated with a recently developed model relating county-level yields of various leguminous crops with BNF rates. We accessed county-level data on annual crop yields for soybeans (Glycine max L.), alfalfa (Medicago sativa L.), peanuts (Arachis hypogaea L.), various dry beans (Phaseolus, Cicer, and Lens spp.), and dry peas (Pisum spp.) for 2006 from the USDA Census of Agriculture (http://www.agcensus.usda.gov/index.php). We estimated the yield of the non-alfalfa leguminous component of hay as 32% of the yield of total non-alfalfa hay (http://www.agcensus.usda.gov/index.php). Annual rates of C-BNF by crop type were calculated using a model that relates yield to C-BNF. We assume yield data reflect differences in soil properties, water availability, temperature, and other local and regional factors that can influence root nodulation and rate of N fixation. We distributed county-specific, C-BNF rates to cultivated crop and hay/pasture lands delineated in the 2006 National Land Cover Database (30 x 30 m pixels) within the corresponding county. C-BNF data described here represent an average input to a typical agricultural land type within a county, i.e., they are not specific to individual crop types. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets). The purpose of this dataset is to provide information that can be used to estimate landscape-level loading of reactive nitrogen from cultivated biological nitrogen fixation (C-BNF) to watersheds, to municipal, agricultural, and water resources management units, and to other management- or ecosystem-relevant spatial units. C-BNF is a major source of reactive N to United States ecosystems and can have both positive (e.g., enhanced crop production and reduced reliance on fossil-fuel based synthetic fertilizers) and negative (e.g., eutrophication of aquatic systems indirectly through manure disposal) impacts. These data can be used to examine correlations with air and water quality characteristics or be fed into terrestrial and aquatic biogeochemical models. The overall goal of EnviroAtlas is to employ and develop the best available science to map indicators of ecosystem services production, demand, and drivers for the nation. completed EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact asNeeded Agriculture Ecosystem Environment Modeling Monitoring theme EPA GIS Keyword Thesaurus 12-digit HUCs Agriculture Ecosystem Ecosystem Services EnviroAtlas Environment Environmental Atlas Modeling Monitoring theme EnviroAtlas Alabama Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas United States Utah Vermont Virginia Washington Washington DC West Virginia Wisconsin Wyoming place None https://edg.epa.gov/EPA_Data_License.html otherRestrictions Use Constraints: None. Please check sources, scale, accuracy, currency and other available information. Please confirm that you are using the most recent copy of both data and metadata. Acknowledgement of the EPA would be appreciated. otherRestrictions Access Constraints: None PUBLIC https://project-open-data.github.io/schema/#accessLevel Standard Technical Controls eng; USA environment farming -128.02839229 -65.20336449 22.7348894 51.6773602 2013-09-20 true Entity and Attribute Information Entity and Attribute Overview: These data are rates of cultivated biological nitrogen fixation in kg N/ha/yr for the year 2006. Sobota et al., submitted to Ecological Applications. N inputs from the cultivation of legumes (C-BNF), which possess a symbiotic relationship with N-fixing bacteria, were calculated with a recently developed model relating county-level yields of various leguminous crops with BNF rates (Sobota et al, submitted). We accessed county-level data on annual crop yields for soybeans (Glycine max L.), alfalfa (Medicago sativa L.), peanuts (Arachis hypogaea L.), various dry beans (Phaseolus, Cicer, and Lens spp.; hereafter "beans"), and dry peas (Pisum spp.; hereafter "peas") for 2006 from the USDA Census of Agriculture (http://www.agcensus.usda.gov/index.php). We did not include data for seed production because areas harvested for seed comprised <1% of the total area harvested for each crop type (http://www.agcensus.usda.gov/index.php). We estimated the yield of the non-alfalfa leguminous component of hay as 32% of the yield of total non-alfalfa hay. This was based on the average fraction of total non-alfalfa hay made up by an assortment of clover species (Trifolium spp.) for the period 1924 - 1964, the period for which national level data on clover and non-alfalfa hay overlapped (http://www.agcensus.usda.gov/index.php). Our model assumes that crop yield (Y; units of kg grain yr^-1) data reflects differences in soil properties, water availability, temperature, and other local and regional factors that can influence root nodulation and rate of N fixation (Peoples et al. 2009). We corrected Y for moisture content (MF; dry biomass in kg divided by yield biomass in kg) using published USDA coefficients for yield data (Table 1). Based on field studies, we used four plant characteristics to convert yield data to C-BNF rates for legume i (Herridge et al. 2008; Yang et al. 2010). These are: 1) the fraction of dry yield biomass that comprises aboveground plant biomass (HI_i), 2) the ratio between total dry plant biomass and aboveground dry plant biomass (TA_i), 3) the fraction of N making up aboveground dry biomass (SN_i), and 4) the fraction of total plant N derived from the atmosphere (Ndfa_i). We also assumed that the N content of belowground dry biomass for all legumes was equivalent to 24% of the N content of aboveground dry plant biomass based on 15N isotope tracer experiments that examined N fixation by a variety of legume species (Rochester et al. 1998). To do this, we calculated an N-specific, total dry biomass-to-aboveground dry biomass ratio for each legume (TA_m_i) with the following equation: (7) TA_m_i =((1/TA_i)+0.24(1-TA_i ))/(1/TA_i) . We calculated total, annual C-BNF at the county scale using the following equation based on the model presented by Herridge et al. (2008): (2) BNF_C = SUM((MF_iY_i/HI_i)( TA_m_iSN_iNdf a_i )| i=1 to k=n . Where BNF_C is C-BNF in terms of the annual mass input of N (kg N yr^1; Table 2). Subscript i refers to different legume crops. Per-area annual C-BNF rates at the county-scale were made using the following equation: (3) BNF_C_A =BNF_C/A_a . Where BNF_C_A is the annual county-scale, per-area C-BNF rate (kg N ha^1 yr^1) and A_a is the area of cultivated crop and hay/pasture (agricultural) in the county during 2006 (ha). All model calculations were conducted in R 2.14.0 (R Development Core Team 2011). We distributed county-specific, C-BNF rates to agricultural lands (30 x 30 m pixels) within the corresponding county (Ruddy et al. 2006). Literature Cited: Cleveland, C. C., A. R. Townsend, D. S. Schimel, H. Fisher, R. W. Howarth, L. O. Hedin, S. S. Perakis, E. F. Latty, J. C. Von Fischer, A. Elseroad, and M. F. Wasson. 1999. Global patterns of terrestrial biological nitrogen (N2) fixation in natural ecosystems. Global Biogeochemical Cycles 13:623-645.; Gronberg, J. A. M., and N. E. Spahr. 2012. County-level estimates of nitrogen and phosphorus from commercial fertilizer for the conterminous United States, 1987-2006. USGS Scientific Investigations Report 2012-5207. Reston, VA.; Herridge, D. F., M. B. Peoples, and R. M. Boddey. 2008. Global inputs of biological nitrogen fixation in agricultural systems. Plant Soil 311:1-18.; Kellogg R. L., C. H. Lander, D. C. Moffitt, and N. Gollehon. 2000. Manure nutrients relative to the capacity of cropland and pastureland to assimilate nutrients: spatial and temporal trends for the United States. US Department of Agriculture nps00-0579. Washington, DC.; Peoples, M. B., J. Brockwell, D. F. Herridge, I. J. Rochester, B. J. R. Alves, S. Urquiaga, R. M. Boddey, F. D. Dakora, S. Bhattarai, S. L. Maskey, C. Sampet, B. Rerkasem, D. F. Khan, H. Hauggaard-Nielsen, and E. S. 2009. The contributions of nitrogen-fixing crop legumes to the productivity of agricultural systems. Symbiosis 48:1-17.; R Development Core Team. 2011. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org/.; Rochester, I. J., M.B. People, G.A. Constable, and R.R. Gault. 1998. Faba beans and other legumes add nitrogen to irrigated cotton cropping systems. Australian. Journal of Experimental Research 38:253-260.; Ruddy BC, Lorenz DL, and Mueller DK. 2006. County-level estimates of nutrient inputs to the land surface of the conterminous United States, 1982-2001. USGS NAQWA Scientific Investigations Report 2006-501. Reston, VA.; Sanford, W. E., and D. L. Selnick. 2013. Estimation of evapotranspiration across the conterminous United States using regression with climate and land-cover data. Journal of the American Water Resources Association 49:217-230.; Sobota, D. J., J. E. Compton, and J. A. Harrison. Past and present contributions of crop biological nitrogen fixation to reactive nitrogen loading in the United States. Submitted to Ecological Applications.; Vitousek, P.M., D. N. L. Menge, S. C. Reed, and C. C. Cleveland. 2013. Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems. Philosophical Transactions of the British Royal Society 368:1471-2970.; Yang, J. Y., C. F. Drury, X. M. Yang, R. De Jong, E. C. Huffman, C. A. Campbell, and V. Kirkwood. 2010. Estimating biological N2 fixation in Canadian agricultural land using legume yields.Agriculture, Ecosystems and Environment 137:192-201.; Table 1. Fixed parameter values for the regression equations (equations 1 - 5) describing the correlation of actual evapotranspiration with climate and land use/land cover variables. Parameter Value T0 17.737 P0 938.89 m 1.9897 n 2.4721 a 10,000 b 18.457 c 0.173 e 0.297 h 0.094 j 0.236 k 0.382 r 0.400 Table 2: Values for model parameters used to calculate C-BNF. MF=moisture factor (fraction describing dry biomass divided yield biomass); HI=harvest index (fraction describing dry yield biomass divided by total aboveground dry biomass); SN=shoot nitrogen (fraction describing mass of nitrogen divided by total aboveground dry biomass); TA=ratio of total plant dry biomass to aboveground dry biomass; Ndfa=nitrogen derived from the atmosphere (fraction of total plant N derived from N fixation annually). References for parameter values are found in Sobota et al., submitted. Crop: Alfalfa. Model parameter: MF Value: 0.8 Model parameter:HI Value: 0.92 Model parameter:SN Value: 0.0280 Model parameter:TA Value: 1.77 Model parameter: Ndfa Value: 0.71 Crop: Beans. Model parameter:MF Value: 0.89 Model parameter:HI Value: 0.49 Model parameter:SN Value: 0.0141 Model parameter:TA Value: 1.27 Model parameter:Ndfa Value: 0.40 Crop: Non-alfalfa leguminous hay. Model parameter:MF Value: 0.88 Model parameter:HI Value: 0.92 Model parameter:SN Value: 0.0260 Model parameter:TA Value: 1.32 Model parameter:Ndfa Value: 0.70 Crop: Peas. Model parameter: MF Value: 0.89 Model parameter:HI Value: 0.44 Model parameter:SN Value: 0.0219 Model parameter:TA Value: 1.30 Model parameter:Ndfa Value: 0.55 Crop: Peanuts. Model parameter:MF Value: 0.90 Model parameter:HI Value: 0.46 Model parameter:SN Value: 0.0217 Model parameter:TA Value: 1.33 Model parameter:Ndfa Value: 0.58 Crop: Soybeans Model parameter:MF Value: 0.87 Model parameter:HI Value: 0.49 Model parameter:SN Value: 0.0327 Model parameter:TA Value: 1.28 Model parameter:Ndfa Value: 0.52 Entity and Attribute Detail Citation: https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas distributor https://enviroatlas.epa.gov/download/CONUS_metrics_FGDB.zip download Download The URL providing direct access to the downloadable dataset. download https://enviroatlas.epa.gov/download/CONUS_metrics_CSV.zip ESRI:ArcGIS API The endpoint of a web service to access the dataset (REST endpoint, WMS GetCapabilities URL, or a SOAP WSDL endpoint). webMapService https://www.epa.gov/enviroatlas/enviroatlas-data information Documentation URL for accessing related documents such as data dictionary, technical information about a dataset, developer documentation, etc. information https://www.epa.gov/enviroatlas information Home Page Alternative landing page used to redirect user to a contextual, Agency-hosted "homepage" for the Dataset or API information dataset Horizontal Positional Accuracy Report Data were collected using methods that have unknown accuracy (EPA National Geospatial Data Policy [NGDP] Accuracy Tier 10). For more information, please see EPA's NGDP at https://epa.gov/geospatial/policies.html Features represented have not been tested for completeness Features represented have not been tested for completeness Tests for integrity have not been performed. This lineage was generated by the FGDC CSDGM to 19139 transformation C-BNF modeled as a function of county-scale leguminous crop yield data. 2013-01-01T00:00:00 Modeled C-BNF data distributed to cultivated crop and hay/pasture lands in the 2006 National Land Cover Database. 2013-01-01T00:00:00 Converted the NHDPlus V2 WBD Snapshot, EnviroAtlas version - Conterminous United States to a 30m raster snapped to the 2011 NLCD. 2015-03-09T00:00:00 Used ArcMap zonal statistics as table to find the mean value for each 12-digit HUC. 2015-03-09T00:00:00 unknown 2029-07-23 This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2024-02-09T11:11:00 version of the FGDC CSDGM to ISO 19139 transform. EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact