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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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Datasets

15 datasets

Walnut Gulch Experimental Watershed, Kendall (Carbon Dioxide and Water Flux)

    Atmospheric carbon dioxide and moisture concentrations were measured with an infrared gas analyzer (IRGA) (LI-6262, LI-COR, Inc. Lincoln, Nebraska, USA). Measurements were made from 1997 through the present at the Kendall site. The meteorological data and Bowen ratio energy balance systems (BREB) (Model 023/CO2 Campbell Scientific Inc., Logan, Utah, USA) data are used to calculate carbon dioxide and evapotranspiration (ET) fluxes.

    Walnut Gulch Experimental Watershed, Lucky Hills (Carbon Dioxide and Water Flux)

      The meteorological data and Bowen ratio energy balance systems (BREB) (Model 023/CO2 Campbell Scientific Inc., Logan, Utah, USA) data are used to calculate carbon dioxide and evapotranspiration (ET) fluxes at Lucky Hills. The stored Bowen ration instrument data from the measurement site were transmitted by radio daily to our research station in Tombstone, AZ.

      LTAR Walnut Gulch Experimental Watershed Lucky Hills Phenocam

      NAL Geospatial Catalog
        A stationary camera overlooking the Lucky Hills sub-watershed in the Walnut Gulch Experimental Watershed used to track vegetation phenology (RGB and IR imagery). Images are taken every 30 minutes between 4:00am and 10:30pm local standard time.

        LTAR Walnut Gulch Experimental Watershed Kendall Phenocam

        NAL Geospatial Catalog
          A stationary camera overlooking the Kendall sub-watershed in the Walnut Gulch Experimental Watershed used to track vegetation phenology (RGB and IR imagery). Images are taken every 30 minutes between 4:00am and 10:30pm local standard time.

          LTAR Walnut Gulch Experimental Watershed DAP GIS Layers

          NAL Geospatial Catalog
            The USDA-ARS Southwest Watershed Research Center (SWRC) operates the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona as an outdoor laboratory for studying semiarid rangeland hydrologic, ecosystem, climate, and erosion processes.

            US Department of Agriculture Soil Climate Analysis Network (SCAN) site 2026 data, Walnut Gulch #1, Arizona

            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 2026, "Walnut Gulch #1," located in Cochise County, Arizona. 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 4500 feet; data has been continuously collected there since 1999-03-19.

              Walnut Gulch Experimental Watershed, Arizona (Runoff)

              NAL Geospatial Catalog
                The Walnut Gulch Experimental Watershed (WGEW) runoff database has the longest period of record of runoff in the world for a semiarid location, with data collection beginning in 1953. Runoff occurs at Walnut Gulch primarily as a result of convective thunderstorms during the months of July through September. Runoff volume and flow duration are correlated with drainage area as a result of the limited areal extent of runoff producing rainfall and transmission losses or infiltration of the flood wave into the channel alluvium.