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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

    602 datasets

    SGP97 GCIP/NESOB Surface: National Climatic Data Center (NCDC) Daily Evaporation Dataset

      This dataset was formed by extracting evaporation data from the GCIP/Enhanced Seasonal Observing Period 1997 (GCIP/ESOP-97) NCDC Summary of the Day Co-operative Dataset (TD-3200) for the NESOB 1997 area and time of interest. This NCDC Evaporation Dataset contains data from approximately 14 stations reporting evaporation data for the NESOB 1997 time period (01 April 1997 through 31 March 1998, and in the NESOB 1997 domain (approximately 94.5W to 100.5W longitude and 34N to 39N latitude).

      SGP97 GCIP/NESOB Surface: National Centers for Environmental Prediction (NCEP) Miscellaneous Hourly Precipitation Data

        This dataset contains all hourly precipitation data from the National Centers for Environmental Prediction (NCEP) stations. Stations that reported at standard or incremental times are also included in the various NESOB 1997 precipitation composite datasets. The miscellaneous precipitation dataset contains data from stations in the NESOB 1997 domain (94.5 W to 100.5W longitude and 34N to 39N latitude) and time period (01 April 1997 through 31 March 1998).

        SGP97 GCIP/NESOB Surface: National Centers for Environmental Prediction (NCEP) Miscellaneous Daily Precipitation Data

          This dataset contains all daily precipitation data from the National Centers for Environmental Prediction (NCEP) stations. Stations that reported at standard or incremental times are also included in the various NESOB 1997 precipitation composite datasets. The miscellaneous daily precipitation dataset contains data from stations in the NESOB 1997 domain (94.5 W to 100.5W longitude and 34N to 39N latitude) and time period (01 April 1997 through 31 March 1998).

          SGP97 GCIP/NESOB Surface: Hourly Surface Meteorological Composite

            This Surface Composite contains data for the ARM/GCIP NESOB 1997 time period (01 April 1997 through 31 March 1998) and for the ARM/GCIP NESOB 1997 domain only. The ARM/GCIP NESOB 1997 domain is approximately 34N to 39N latitude and 94.5W to 100.5W longitude. The ARM/GCIP NESOB 1997 Hourly Surface Composite contains ten metadata parameters and 38 data parameters and flags. The metadata parameters describe the station location and time at which the data were collected.

            SGP97 GCIP/EOP Surface: Precipitation NCEP/EMC 4KM Gridded Data (GRIB) Radar Est. w/bias removal UBR -2001

            NAL Geospatial Catalog
              The temporal coverage for this dataset is as follows: Begin datetime: 1997-04-23 00:00:00, End datetime: 2001-12-31 23:59:59. This dataset contains the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center (EMC) 4 KM GRIB radar estimate after bias removal ("UBR") data. A prototype, real-time, hourly, multi-sensor National Preciptation Analysis (NPA) has been developed at NCEP in cooperation with the Office of Hydrology (OH). This analysis merges two data sources that are currently being collected in real-time by OH and NCEP.

              SGP97 GCIP/EOP Surface: Precipitation NCEP/EMC 4KM Gridded Data (GRIB) Radar Est. no bias removal RAD-2001

              NAL Geospatial Catalog
                This dataset contains the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center (EMC) 4 KM GRIB radar estimate (no bias removal) "RAD" data. A prototype, real-time, hourly, multi-sensor National Preciptation Analysis (NPA) has been developed at NCEP in cooperation with the Office of Hydrology (OH). This analysis merges two data sources that are currently being collected in real-time by OH and NCEP.

                SGP97 Electronically Scanned Thinned Array Radiometer Quick Look Images

                NAL Geospatial Catalog
                  The core of the 1997 experiment involves the deployment of the L-band Electronically Scanned Thinned Array Radiometer (ESTAR) for daily mapping of surface soil moisture over an area greater than 10,000 km2 and a period on the order of a month. The region selected for investigation is the best instrumented site for surface soil moisture, hydrology and meteorology in the world. This includes the USDA/ARS Little Washita Watershed, the USDA/ARS facility at El Reno, Oklahoma, the ARM/CART central facility, as well as the Oklahoma Mesonet. The region covered by the experiment is 34.5 to 37 North latitude and 97 to 99 West longitude. The aircraft mapping took place over the period 18 June to 18 July 1997. This dataset presents brightness temperature images from the Electronically Scanned Thinned Array Radiometer (L band passive microwave radiometer)

                  SGP97 ARM Soil Water Retention Data Set

                  NAL Geospatial Catalog
                    The temporal coverage for this dataset is as follows: Begin datetime: 1995-10-01 00:00:00, End datetime: 2001-03-31 23:59:59. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Soil Water Retention Data Set is one of the various sub-surface data sets developed for the ARM/GCIP (Global Energy and Water Cycle Experiment (GEWEX) Continental-scale International Project) 1996 Near-Surface Observation (NESOB-96) Data Set. This data set contains a table for each of the ARM SWATS (Soil Water and Temperature System) sites at the SGP site containing the observed soil water retention data as obtained from laboratory tests using pressure plates and hanging columns. The soil characterizations were perfomed by Oklahoma State University.

                    SGP97 ARM Soil Texture Data Set

                    NAL Geospatial Catalog
                      The temporal coverage for this dataset is as follows: Begin datetime: 1995-10-01 00:00:00, End datetime: 2001-03-31 23:59:59. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Soil Texture Data Set is one of the various sub-surface data sets developed for the ARM/GCIP (Global Energy and Water Cycle Experiment (GEWEX) Continental-scale International Project) 1996 Near-Surface Observation (NESOB-96) Data Set. This data set contains a summary table of the percentages of sand, silt, and clay fractions in each soil layer at each of the ARM SWATS (Soil Water and Temperature System) sites at the SGP site. Also included is the corresponding USDA texture class as determined from the "soil triangle". The soil characterizations were perfomed by Oklahoma State University.

                      SGP97 ARM Soil Particle Size Data Set

                      NAL Geospatial Catalog
                        The temporal coverage for this dataset is as follows: Begin datetime: 1995-10-01 00:00:00, End datetime: 2001-03-31 23:59:59. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Soil Particle Size Data Set is one of the various sub-surface data sets developed for the ARM/GCIP (Global Energy and Water Cycle Experiment ?GEWEX? Continental-scale International Project) 1996 Near-Surface Observation (NESOB-96) Data Set. This data set contains tables of the laboratory data for each soil layer at each of the ARM SWATS (Soil Water and Temperature System) sites at the SGP site. The soil characterizations were perfomed by Oklahoma State University.