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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

    632 datasets

    Data from: Conservation Practices Induce Tradeoffs in Soil Function: Observations from the Northern Great Plains

      Near-surface (0-5 cm) measurements of soil physical, chemical, and biological properties over a 3-yr period for contrasting long-term experimental treatments at the USDA-ARS Northern Great Plains Research Laboratory were conducted to quantify soil property responses to crop diversity/intensity, cover crops, and livestock integration under controlled experimental conditions, and land use (dryland cropping, native grassland, untilled pasture) on working farms and ranches, all on a common soil type in southcentral North Dakota, USA.

      Data from: Vegetation index-based partitioning of evapotranspiration is deficient in grazed systems

        The dataset includes 30 minutes values of partitioned evaporation (E) and transpiration (T), T:ET ratios, and other ancillary datasets for three ET partitioning methods viz. Flux Variance Similarity (FVS) method, Transpiration Estimation Algorithm (TEA), and Underlying Water Use Efficiency (uWUE) method for the three wheat sites. The dataset also contains remote sensing-derived Enhanced Vegetation Index (EVI) data for each site.

        Assessing the rate and reversibility of large herbivore effects on community composition in a semi-arid grassland ecosystem with GZTX data on the Central Plains Experimental Range, Nunn, Colorado, USA 1992-2017

          Data supporting empirical evaluation of the effects of grazing on semi-arid grassland hypothesized by State-and-Transition models using a 25-year grazing exclosure reversal experiment in the Great Plains, US. We document rapid, reversible and symmetric effects of the imposition and removal of grazing between 1992-2017 due to differences in the rate of increase in cover of C3 midgrasses, litter and bare ground.

          US Department of Agriculture Soil Climate Analysis Network (SCAN) site 2027 data, Little River, Tift County, Georgia

          NAL Geospatial Catalog
            This dataset contains air temperature, relative humidity, precipitation, solar radiation, wind speed, soil temperature, and soil moisture data from the Soil Climate Analysis Network (SCAN) site 2027, "Little River," located in Tift County, Georgia. The dataset links to a National Resources Conservation Service data request form, from which available data can be queried. The data collection site is at an elevation of 350 feet; data has been continuously collected there since 1999-05-19.

            Walnut Gulch Experimental Watershed, Arizona (Meteorologic)

            NAL Geospatial Catalog
              The Southwest Watershed Research Center (SWRC) has operated Walnut Gulch Experimental Watershed (WGEW), located in the vicinity of Tombstone, Arizona, for more than 50 years. A 17 year (1990-2006) meteorological and soil hydrology database has been established by the USDA Agricultural Research Service, SWRC.

              Upper Washita River Experimental Watersheds: Nutrient Water Quality Data

              NAL Geospatial Catalog
                Climate variability, changing land use and management, and dynamic policy environments are the main reasons why long-term water quality data sets are needed to understand and predict possible water quality outcomes to alternative future scenarios. Such data sets were acquired by the USDA-ARS in three watersheds in Oklahoma: the Southern Great Plains Research Watershed (SGPRW), the Little Washita River Experimental Watershed (LWREW), and the Fort Cobb Reservoir Experimental Watershed (FCREW).