U.S. flag

An official website of the United States government

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

Filter by Program

Filter by author name

Filter by Funding Source

Filter by user-supplied tag

Filter by Ag Data Commons keyword

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

    610 datasets

    Reynolds Creek Experimental Watershed, Idaho (Snow)

      Snow is the dominant form of precipitation in the Reynolds Creek Experimental Watershed (RCEW). Seven snow course sites were established in 1961, and one additional site was added in 1970. All sites are located in the high-elevation southern extent of the basin, where snow accumulation is greatest. Snow water equivalent (SWE) and depth have been sampled at multiple locations in RCEW since 1961. These data have been collected using snow tube methods that are generally considered the standard for manual measurement of SWE and snow depth. Snow water equivalent (SWE) has been measured at eight locations in RCEW every 2 weeks throughout the snow season (December 1 to June 1) for 35 water years (1962-1996). SWE was continuously monitored at site 176x07 using a snow pillow for 14 water years (1983-1996).

      Gulf Atlantic Coastal Plain LTAR Dataset: NFARM, Inorganic N, & C Production, 2016-2018

        In situ denitrification rates in intact soil cores from the Gulf Atlantic Coastal Plain (GACP) LTAR site in GA quantified by directly measuring dinitrogen (N2) and nitrous oxide (N2O) production via the Nitrogen-Free Air Recirculation Method (N-FARM) from 2016-2018. 10-day laboratory incubations provided estimates of ancillary soil data, including microbial respiration and potential net N mineralization and nitrification.

        Upper Chesapake Bay LTAR Dataset: NFARM, Inorganic N, & C Production, 2016-2018

          In situ denitrification rates in intact soil cores from the Upper Chesapeake Bay (UCB) LTAR site in PA quantified by directly measuring dinitrogen (N2) and nitrous oxide (N2O) production via the Nitrogen-Free Air Recirculation Method (N-FARM) from 2016-2018. 10-day laboratory incubations provided estimates of ancillary soil data, including microbial respiration and potential net N mineralization and nitrification.

          Central Mississippi River Basin LTAR Dataset: NFARM, Inorganic N, & C Production, 2016-2018

            In situ denitrification rates in intact soil cores from the Central Mississippi River Basin (CMRB) LTAR site in MO quantified by directly measuring dinitrogen (N2) and nitrous oxide (N2O) production via the Nitrogen-Free Air Recirculation Method (N-FARM) from 2016-2018. 10-day laboratory incubations provided estimates of ancillary soil data, including microbial respiration and potential net N mineralization and nitrification.

            Long-Term Agricultural Research (LTAR) network - Meteorological Collection

              The LTAR network maintains stations for standard meteorological measurements including, generally, air temperature and humidity, shortwave (solar) irradiance, longwave (thermal) radiation, wind speed and direction, barometric pressure, and precipitation. Many sites also have extensive comparable legacy datasets.

              Long-Term Agroecosystem Research Network regions, 2018 version

                The Long-Term Agroecosystem Research Network, consisting of 18+ research locations, is conducting research on the sustainable intensification of agroecosystems. To enable coordinated network level research, a spatial framework is required to facilitate analysis. This dataset contains a geodatabase of three new maps describing regional boundaries for the LTAR Network titled "Long-Term Agroecosystem Research Network regions, 2018 version.”

                Data from: Threshold Behavior of Catchments with Duplex Hillslope Soils Feeding Soil Pipe Networks

                  This dataset corresponds with two published studies conducted on loess covered catchments in northern Mississippi, USA within the Goodwin Creek Experimental Watershed that contain extensive networks of soil pipes and corresponding collapse features. These loess soils contain fragipan layers that were found to perch water, thereby initiating the piping processes. The dataset contains data from two papers, specifically these include: (i) the spatial distribution of soil pipe collapses and their size measurements from the Wilson et al. (2015) paper, and (ii) hydrologic measurements of perched water tables on hillslopes, water levels of selected soil pipe locations, and precipitation from the Wilson et al. (2017) paper.

                  NAL Geodata

                    The United States Department of Agriculture National Agricultural Library Geospatial Data catalog contains geographic location-based agricultural research data, imagery, research location context, and more. Users can search records representing a variety of datasets, maps and graphics, aerial and phenocam images, and other services.