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Long Term Agroecosystem Research Overview

In pursuit of sustainable U.S. agriculture, the U.S. Department of Agriculture (USDA) launched the Long-Term Agroecosystem (LTAR) network. The LTAR network is composed of 18 locations distributed across the contiguous United States working together to address national and local agricultural priorities and advance the sustainable intensification of U.S. agriculture.

The LTAR network represents a range of major U.S. agroecosystems, including annual row cropping systems, grazinglands, and integrated systems representative of roughly 49 percent of cereal production, 30 percent of forage production, and 32 percent of livestock production in the United States. Furthermore, the LTAR sites span geographic and climatic gradients representing a variety of challenges and opportunities to U.S. agriculture.

The LTAR network uses experimentation and coordinated observations to develop a national roadmap for the sustainable intensification of agricultural production. While the LTAR network is a new network, experimentation and measurements began at some LTAR sites more than 100 years ago, while other locations started their research as recently as 19 years ago.

A primary goal of LTAR is to develop and to share science-based findings with producers and stakeholders. Tools, technologies, and management practices resulting from LTAR network science will be applied to the sustainable intensification of U.S. agriculture. Technical innovations, including new production techniques, genetics, and sensor infrastructure applied at the farm/ranch level can increase the capacity for adaptive management, reduce time and operational costs, and increase profits and the quality of life for producers.

For full list of LTAR sites, view the sites matrix at https://ltar.ars.usda.gov/sites/.

For more information about the LTAR network visit: https://ltar.ars.usda.gov

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LTAR Research Sites

Data from the following LTAR sites are presented. They are related to topics such as agricultural sustainability, climate change, ecosystem services, and natural resource conservation at the watershed or landscape scale.

  • Archbold Biological Station (ABS), Venus, FL
  • Cook Agronomy Farm (CAF), Pullman, WA
  • Central Mississippi River Basin (CMRB), Columbia, MO
  • Central Plains Experimental Range (CPER), Cheyenne, WY; Fort Collins, CO; Nunn, CO
  • Eastern Corn Belt (ECB), Columbus, OH; West Lafayette, IN
  • Gulf Atlantic Coastal Range (GACP), Tifton, GA
  • Great Basin (GB), Boise, ID; Burns, OR
  • Jornada Experimental Range (JER), Las Cruces, NM
  • Kellogg Biological Station (KBS), southwestern MI
  • Lower Mississippi River Basin (LMRB), Oxford, MS; AR; LA; MO
  • Northern Plains (NP), Mandan, ND
  • Platte River-High Plains Aquifer (PRHP), Lincoln, NE
  • Southern Plains (SP), El Reno, OK
  • Texas Gulf (TG), Riesel, TX
  • Upper Chesapeake Bay (UCB), University Park, PA
  • Upper Mississippi River Basin (UMRB), Ames, IA; MN; WI
  • Walnut Gulch Experimental Watershed (WGEW), Tucson, AZ; Tombstone, AZ
  • Lower Chesapeake Bay (LCB), Beltsville, MD

    • Datasets

    618 datasets

    SGP97 Upper Air: DOE ARM 915 MHz Profiler RASS

      This data set contains hourly average profiles of wind speed and direction, u and v wind components (from the Radar Wind Profiler), and virtual temperature (from the RASS [Radio Acoustic Sounding System]).

      SGP97 Upper Air: DOE ARM 50 MHz Profiler Winds

        This data set covers the period from 1 June through 31 July 1997. The SGP97 domain is approximately 97W to 99W longitude and 34.5N to 37N latitude. These data are in their original NetCDF format. The 50-MHz Radar Wind Profiler/RASS (RWP50) measures wind profiles from (nominally) 2 to 12 km and virtual temperature profiles from 2 to 4 km.

        SGP97 Upper Air: DOE ARM 50 MHz Profiler RASS

          This data set covers the period from 1 June through 31 July 1997. The SGP97 domain is approximately 97W to 99W longitude and 34.5N to 37N latitude. These data are in their original NetCDF format. The 50-MHz Radar Wind Profiler/RASS (RWP50) measures wind profiles from (nominally) 2 to 12 km and virtual temperature profiles from 2 to 4 km. It operates by transmitting electromagnetic energy into the atmosphere and measuring the strength and frequency of backscattered energy.

          SGP97 Surface: NCDC Summary of the Day COOP Precipitation Data

          NAL Geospatial Catalog
            The primary thrust of the cooperative observing program is the recording of 24-hour precipitation amounts. The observations are for the 24-hour period ending at the time of observation. Observer convenience or special program needs mean that observing times vary from station to station. However, the vast majority of observations are taken near either 7:00 AM or 7:00 PM local time. The National Weather Service (NWS) Cooperative Observer Daily Precipitation dataset was formed by extracting the daily incremental precipitation values provided in the National Climatic Data Center (NCDC) TD 3200 dataset.

            SGP97 Surface: NCDC Summary of the Day COOP Dataset

            NAL Geospatial Catalog
              This NCDC Co-operative Observer (COOP) dataset contains data from sixty-two stations for the SGP 1997 time period (18 June 1997 through 18 July 1997) and in the SGP 1997 domain (approximately 97W to 99W longitude and 34.5N to 37N latitude). The primary thrust of the cooperative observing program is the recording of 24-hour precipitation amounts, but approximately 55% of the stations also record maximum and minimum temperatures.

              SGP97 Surface: High Plains Climate Network Data

              NAL Geospatial Catalog
                This dataset covers the complete SGP97 time period (18 June 1997 through 18 July 1997) and for the SGP97 domain. The SGP97 domain is approximately 97W to 99W longitude and 34.5N to 37N latitude. The HPCN dataset contains different parameters depending upon the reporting station. Each station provides Station Name, State, and Identification Number preceding that station's data within the dataset.

                SGP97 Surface: DOE ARM Energy Balance Bowen Ratio (EBBR) Data

                NAL Geospatial Catalog
                  The temporal coverage for this dataset is as follows: Begin datetime: 1997-06-01 00:00:00, End datetime: 1997-07-31 23:59:59. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program operates a network of 12 Energy Balance Bowen Ration (EBBR) stations at its Southern Great Plains site. EBBR provides 30-min observations of latent and sensible heat flux along with net radiation, atmospheric pressure, bowen ratio, wind speed and direction, and the following parameters at five locations surrounding the sites: soil moisture, soil temperature, soil heat flow, soil heat capacity and soil heat flow at the surface.

                  SGP97 Surface: DOE ARM Baseline Surface Radiation Network (BSRN) Radiation Data

                  NAL Geospatial Catalog
                    The temporal coverage for this dataset is as follows: Begin datetime: 1997-06-01 00:00:00, End datetime: 1997-07-31 23:59:59. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program operates a Baseline Surface Radiation Network (BSRN) station at the Central Facility (located near Lamont, in north-central Oklahoma) of its Southern Great Plains site. BSRN provides 1-min observations of direct-beam normal solar irradiance, downwelling hemispheric diffuse solar irradiance, downwelling hemispheric solar irradiance and downwelling hemispheric infrared irradiance.

                    SGP97 Sub-Surface: PSU Soil Properties Data (Roughness)

                    NAL Geospatial Catalog
                      The temporal coverage for this dataset is as follows: Begin datetime: 1997-06-01 00:00:00, End datetime: 1997-07-31 23:59:59. This data set was developed by the EOS IDS Team at Penn State for the Southern Great Plains 1997 (SGP-97) project. The following data coverages are available: DEM, Landcover and Landuse, Gauge Stations, Available Water Capacity, Bulk Density, Depth to Bedrock, Hydrologic Soils Group, Mapunits, Percent Water, Porosity, Rock Fragment Class, Rock Volume, Soil Fractions, and Surface Soil Texture.

                      SGP97 Sub-Surface: PSU Soil Properties Data (Hydraulic)

                      NAL Geospatial Catalog
                        The temporal coverage for this dataset is as follows: Begin datetime: 1997-06-01 00:00:00, End datetime: 1997-07-31 23:59:59. This data set was developed by the EOS IDS Team at Penn State for the Southern Great Plains 1997 (SGP-97) project. The following data coverages are available: DEM, Landcover and Landuse, Gauge Stations, Available Water Capacity, Bulk Density, Depth to Bedrock, Hydrologic Soils Group, Mapunits, Percent Water, Porosity, Rock Fragment Class, Rock Volume, Soil Fractions, and Surface Soil Texture.