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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Water Quality and Ecology Research » Research » Research Project #441531

Research Project: Enhancing Long-Term Agroecosystem Sustainability of Water and Soil Resources Through Science and Technology

Location: Water Quality and Ecology Research

Project Number: 6060-13660-009-000-D
Project Type: In-House Appropriated

Start Date: Jan 26, 2022
End Date: Jan 25, 2027

1. Assess and quantify impacts of soil and water management strategies in agroecosystems of the Lower Mississippi River Basin (LMRB). 1.A. Examine water management strategies to assess tradeoffs between groundwater sustainability benefits and ecological costs. 1.B. Quantify the influence of soil and water management strategies on water availability and quality, soil health, and wildlife habitat. 2. Evaluate and measure how management practices influence processes to improve water quality, ecosystem services, and ecological integrity. 2.A. Evaluate novel ecological indicators and stressor-response relationships to measure success of best management practices in agricultural watersheds. 2.B. Evaluate how management practices influence processes related to soil health and water quality in agricultural watersheds. 3. Analyze, synthesize, and forecast impacts of implementing conservation practices within agricultural landscapes. 3.A. Forecast and analyze impacts of climate change on the effectiveness of conservation practices. 3.B. Quantify the impacts of conservation practices on aquatic and terrestrial resources in the LMRB. 4. Enhance long-term sustainability of agroecosystems through regional and national (LTAR network) studies that quantify agronomic and environment responses to aspirational management strategies and changing climate. 4.A. Develop the LMRB LTAR site through contributions in monitoring and experimentation to meet network goals. 4.B. Establish a network of LTAR sites distributed regionally and nationally to quantify changes in soil health, water quality and aquatic ecology in LTAR watersheds.

Many experiments described in the following involve collection and analysis of water quality samples from field sites within the Lower Mississippi River Basin. Data acquisition (sample collection, preservation, handling, analysis, quality control), except where otherwise noted, follows standard procedures (APHA, 2005). Base flow samples are collected manually, while storm event or runoff samples are collected using automated pumping samplers (ISCO GLS Compact Composite Samplers) activated by acoustic Doppler water level and area velocity water flow sensors (ISCO 2100). All samples are placed on ice for transport to the laboratory for analysis and held in cold storage (4o C). Storm samples are retrieved within 24 h of collection. All water samples are analyzed for total and dissolved solids (drying at 105o C), total P and total Kjeldahl N (block digestion and flow injection analysis using a Lachat QuikChem® 8500 Series 2 Flow Injection Analysis System). Additional analyses conducted for certain experiments include hardness (EDTA titrimetric method), alkalinity (titration method), turbidity (calibrated Hach electronic turbidimeter); NH4-N, NO3-N, NO2-N, and soluble (filterable) P (all with the Lachat system), and chlorophyll a (pigment extraction with spectrophotometric determination). Pesticide analyses are conducted using solvent (hexane) and KCl extraction prior to analysis on a gas chromatograph. Soil gas flux is measured using a LiCOR 870 soil gas flux system.