Location: Southeast Watershed Research
Project Number: 6048-13000-027-000-D
Project Type: In-House Appropriated
Start Date: Feb 7, 2017
End Date: Feb 6, 2022
Objective:
1. Quantify and assess the interactions among agroecosystems and landscape components and their impacts on water supply and water quality in agricultural watersheds of the southeastern U.S.
2. Quantify and assess the effects of agricultural conservation practices and managed land-use interfaces at field, landscape, and watershed scales in agricultural watersheds of the southeastern U.S.
3. As part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the Gulf Atlantic Coastal Plain (GACP), use the Little River Experimental Watershed (LREW) LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Gulf Atlantic Coastal Plain (GACP) region. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network includes research and data management in support of the ARS GRACEnet and/or Livestock GRACEnet projects.
4. Utilize landscape and watershed scale assessment models to evaluate the long-term sustainability of agricultural watersheds.
Approach:
The research integrates field, landscape, and watershed observations. As such, research sites are located at multiple scales each supporting watershed observations. The SEWRL operates watershed facilities Little River Experimental Watershed (LREW) that are the basis for our long-term hydrology and natural resources research. In addition to these watersheds, the SEWRL has established long-term research at plot (~0.2 Ha) and field (> 10 Ha) scales. The objectives in this plan contribute to the LTAR Common Experiment over-arching hypothesis that “aspirational treatments will increase overall carbon stocks and in particular, soil carbon…leading to increased ecosystem resiliency”. Individual sub-objectives are focused on providing an improved understanding of spatial and temporal drivers and ecosystem services responses associated with the three Common Experiment sub-hypotheses: 1) The magnitude, direction and rate of change will vary with topographic and soil characteristics of the landscape; 2) Sustainable ecosystem productivity, yield, and yield quality will be significantly improved by the development of specific and adaptive G x E x M x Social x Economic systems; and 3) Biologically-based inputs will drive the rate and magnitude of carbon stock increases (e.g., nutrient cycling, insect comminution, decomposition, etc.). The experiments presented are designed as an integrated systems approach to understanding processes at the plot-to-landscape scale using the LREW as the synthesis scale for testing and verification of the Long Term Agroecosystem Research Common Experiment hypothesis. Each objective and sub-objective is designed to address selected spatial and temporal scale processes, provide information for qualifying extrapolations between scales, and/or explore novel technical approaches for characterizing ecosystems services within the LREW. We will use remote sensing, geospatial modeling, statistical modeling and process modeling to evaluate linkages and identify information gaps across scales. Specific research will: 1) characterize the impacts that agricultural land management and land-cover have on water resources in southern coastal plain watersheds; 2) examine relationships between conservation practices (including winter cover), indicators of productivity (e.g. SOC, NPP), other drivers of land cover change, and water quality; 3) characterize composition of DOM with land-use; 4) quantify differences between watersheds with agricultural livestock impacts to watersheds with minimal agricultural livestock impact; 5) quantify stream flow and chemistry differences between urbanized and agricultural watersheds; 6) quantify the impact of agricultural irrigation ponds on watershed water balance; 7) quantify differences in provisioning and regulating ecosystem services between typical and aspirational agricultural production systems; 8) compare spatial and temporal variations between provisioning and regulating ecosystems services; and 9) use landscape and watershed scale assessment models to evaluate the long-term sustainability of agricultural watersheds.
