LTAR and PHACE Research and Data Collection

Long Term Agro-ecosystem Research (LTAR) network

This network of 18 sites of experimental watersheds and rangelands nationwide addresses large-scale, multi-year research, environmental management testing and technology transfer related to the nation's agricultural ecosystems. The LTAR network will provide data that can be used in the development of innovative management systems that increase the resilience of agricultural ecosystems in the face of rapid environmental and socioeconomic change, and can help assess the environmental and societal impacts of different agricultural practices and land uses within a particular landscape. Information from LTAR also can contribute to the development of agricultural production systems that maximize energy conservation and reduce greenhouse gases, while investigating various forms of incentives to encourage on-farm adoption and mitigation, and optimize biodiversity to conserve and protect natural resources while enhancing agricultural profitability. The LTAR network will interact and collaborate with other national ecological research networks, such as the National Science Foundation's already operational Long Term Ecological Research (LTER) network with 26 sites nationwide, the National Ecological Observatory Network (NEON) now being developed by the National Science Foundation and NEON, Inc, and the USDA Forest Service network of Experimental Forests and Ranges.

Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) 

Agricultural lands to be studied by GRACEnet scientists include both grazing lands (range and pasture) and crop lands (irrigated and dryland). Coordinated multi-location field studies will follow standardized protocols to compare net GHG emissions (carbon dioxide, nitrous oxide, methane), carbon (C) sequestration, and broad environmental benefits under different management systems that: 1) typify existing production practices, 2) maximize C sequestration, 3) minimize net GHG emissions, and 4) meet sustainable production and broad environmental benefit goals (including C sequestration, net GHG emissions, water, air and soil quality, etc.). 

Prairie Heating and Carbon Dioxide Enrichment (PHACE) experiment 

The goal of this experiment is to understand how elevated atmospheric carbon dioxide (CO2) and warming influence plants and soils of the northern mixed-grass prairie.  How do these changes influence the following key components of this native rangeland:

  • Water controls most processes in the semiarid mixed-grass prairie. Elevated CO2 can decrease transpiration and increase water use efficiency and water availability. Warming often increases both evaporation and transpiration.
  • Nitrogen often limits plant productivity and quality, and can become increasingly limiting with elevated CO2.
  • Plant productivity and quality determine the ability of mixed-grass prairie to support grazing by livestock and wildlife, which are in turn key to the sustainability of agriculture and biological diversity.
  • Carbon cycling determines whether mixed-grass prairie sequesters or releases CO2, and therefore whether it contributes to or mitigates climate change. 
  • Plant communities both respond to and influence biogeochemical cycling. In mixed-grass prairie, warm-season and cool-season grasses comprise the majority of plant biomass, while forbs comprise most of plant diversity. Legumes and sub-shrubs are less common, but can respond strongly to elevated CO2.
  • Invasive plants reduce forage production and biological diversity, and can thrive following increases in resource availability, including CO2 and water.