Long Term Agroecosystem Research Overview
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
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.
Daily summary values of averages of readings of the following parameters are made which are based on data recorded on a Campbell CR10(X) data logger: maximum, minimum, and average air temperature; maximum and minimum relative humidity; total preci
Data are photosynthetic rates (Amax) for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%.
Data are pre-dawn water potential for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%.
Stocking rates for cattle, horses, and sheep are provided for the Jornada Experimental Range beginning in 1916. Goats were few and are included as part of the sheep category and not differentiated.
Wet atmospheric fallout (wetfall occurring as precipitation) is collected monthly using an Aerochem Metrics wetfall/dryfall collector located at the LTER weather station.
In conjunction with net primary production studies, consumer and faunal studies are conducted at or near NPP sites using pitfall traps.
Once a month soil water content measurements are made at 10 depths (where possible) at each of 10 access tubes at each of the 15 LTER-II sites using a neutron probe (Campbell Model 503DR Hydroprobe).