We use vegetation cover as a proxy for plant biomass to avoid confounding spatial and temporal variability or confounding the impact of harvesting.
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.
A 4" diameter cylindric graduated rain gage (11" x 0.01" capacity) is mounted on a 4x4 inch diameter redwood post or on a wooden exclosure post next to gate at or near the 15 LTER-II NPP sites.
Average percent coverage of each plant species per 5-meter segment along a 30-meter line intercept perpendicular to each of 91 stations on each of the three LTER-I permanent transects.
The data consists of chemical analyses of dissolved ions in samples of surface runoff from natural rainfall events collected from experimental hydrology plots in creosotebush scrub and grass- land areas of the New Mexico State University Ranch and
East and west boundary fence plant line intercepts - percent cover for 9 species, Jornada Basin, 1982 to 1992