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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

358 datasets

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.

    Manuresheds: Redesigning crop-livestock agriculture for sustainable intensification

      The Long-Term Agroecosystem Research (LTAR) network is exploring the concept of the “manureshed,” the manure-spreadable land in the geographic, environmental, and social radius of a confined livestock operation. To better understand opportunities for expanding manuresheds in the United States, we identified the nationwide, county-level pattern of livestock distribution, manure excess, and crop assimilation of manure nutrients.

      Dryfall deposition chemistry data

      NAL Geospatial Catalog

        Dry atmospheric fallout (dryfall) is collected monthly using an Aerochem Metrics wetfall/dryfall collector located at the LTER weather station. Each sample is analyzed for NO3, NH4, Cl, SO4, Ca, Mg, Na, K, Total N, & Total P.

        SGP97 GCIP/NESOB Surface: Net Radiation and PAR Composite

        NAL Geospatial Catalog

          This 30 minute Net Radiation and Photosynthetically Active Radiation (PAR) Composite is one of several surface-layer data sets provided in the Atmospheric Radiation Measurement(ARM)/Global Energy and Water Cycle Experiment (GEWEX) Continental-Scal