Location: Water Quality and Ecology Research
2018 Annual Report
Objectives
1. Assess and quantify ecological processes that influence water resources in agricultural ecosystems.
1a. Identify and quantify environmental factors that drive processes that are related to retention or removal of agricultural contaminants.
1b. Examine relationships between physical, chemical, and biological factors and ecological responses impacted by agriculture in the Lower Mississippi River Basin.
2. Assess and quantify the benefits of water resource management practices to enhance agricultural ecosystems.
2a. Quantify the long-term effects of conservation practices on aquatic and terrestrial resources in the Lower Mississippi River Basin.
2b. Assess the benefits and risks of management strategies and practices on soil and water resources at multiple scales.
3. Develop a watershed-scale integrated assessment of ecosystem services in agricultural landscapes of the Lower Mississippi River Basin.
3a. Develop technologies and tools to assess water and conservation management strategies in agricultural watersheds.
3b. Evaluate how ecosystem services derived from conservation practices improve water quality and ecology in agricultural watersheds.
4. As part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the Mid-South region, use the Lower Mississippi River Basin 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 Mid-South 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.
4a. Develop the Lower Mississippi River Basin LTAR location addressing issues of long-term agroecosystem sustainability specific to the region, participating in the Shared Research Strategy, and contributing to network-wide monitoring and experimentation goals.
4b. Enhance the Lower Mississippi River Basin CEAP watershed longterm data sets and integrate with other long-term data sets in the Lower Mississippi River Basin to address agroecosystem sustainability at the basin scale.
5. Increase knowledge and understanding of the processes governing movement, storage, and quality of water in the Mississippi River Valley Alluvial Aquifer, and develop technologies to enhance the sustainability of water resources for agriculture.
5a: Develop technologies to increase the provision of abundant, sustainable water resources and associated ecosystem services for irrigated agriculture in the LMRB.
5b: Increase knowledge and understanding of the movement, storage, and quality of water along hydrologic pathways between surface and subsurface units of the LMRB.
Approach
Many experiments described in the following involve collection and analysis of water quality samples from field sites within the Lower Mississippi River Basin (LMRB). 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).
Progress Report
Two mesocosm experiments were conducted evaluating nutrient mitigation capabilities of three emergent aquatic plants in monocultures and mixtures. Samples have recently been processed, and data evaluation is underway. Two additional experiments are planned for summer 2018.
Stream mesocosm systems were repaired and systems were initiated to all for natural microbial colonization to take place. New water quality analyses instrumentation was installed. A mesocosm study with selected hydrologic conditions and additions of carbon and nutrients was conducted. Systems are currently in the preparation process for the next mesocosm experiment.
Physical stressors (temperature, nutrients, and suspended solids) were determined at field sites currently under investigation. Laboratory experiments (bioassays) were to be conducted; however, due to several flood events in late winter, natural algal populations were unavailable to use in these experiments. An additional year was requested to collect natural algal populations for laboratory experimentation.
Long-term (1996-present) assessments in the Conservation Effects Assessment Program (CEAP) Beasley Lake watershed continue. Lake and runoff water quality assessments are ongoing. Three publications from data collected within Beasley Lake have recently been published. Select study results demonstrated that vegetated drainage ditches with vegetated sediment pond best management practices (BMPs) in place were effective in reducing suspended solids loads and moderately effective at reducing nutrient loads in runoff.
Several studies were conducted to determine the impact of tillage and cover crops on contaminant loss and soil properties. Early results indicate a minimum tillage system with a cereal rye cover crop may be implemented without reductions in soybean grain yield; however, additional costs of planting the cover crop will decrease net returns above costs. After two years, zone tillage and rye cover crop systems reduced off-site transport of solids and nutrients compared to a minimum tillage system with no cover crop. Another study examined effects of Austrian winter pea, cereal rye, crimson clover, and tillage radish in a corn field. Results from the 2017 growing season indicate Austrian winter pea and cereal rye decreased corn grain yield by 40% and 45%, respectively. In a rainfall simulation experiment, Austrian winter pea reduced runoff by 24% compared to the control, while cereal rye resulted in greater amounts of nutrients in runoff water. Under furrow irrigation, there was no significant difference in nutrient runoff or infiltration between treatments; however, cover crops increased the length of time for water to reach the tail ditch. Soil and economic analyses are underway.
Assessment of a tailwater recovery system (reservoir and tail ditches) continues in Sunflower County, Mississippi, for its ability to improve water quality and reduce dependence on groundwater resources for crop irrigation. Continuous monitoring and flow-triggered sampling runoff events have three years of storm sampling, while four years of bi-monthly water quality sampling have been completed. Data analyses is ongoing.
Studies examining the use of filter socks filled with sorbent material (e.g. woodchips, biochar, etc.) were planned in 2017 and will be executed beginning in June 2018 and concluding in October 2018. Research locations were secured with collaborators. Small scale research questions are currently being addressed regarding nutrient leaching potential of filter sock material.
The USDA Annualized Agricultural Non-Point Source (AnnAGNPS) pollutant loading model was enhanced to utilize remotely sensed data to improve the characterization of associated topography, soil properties, and management associated with riparian buffers and constructed wetlands within national and international watersheds. Databases associated with the AnnAGNPS model were developed in a tailwater recovery system project in the Mississippi Delta for enhancement of the model and evaluation of the impacts of tail water systems on agricultural ecosystem services. Databases in the Sunflower River Watershed system in the Mississippi Delta were assembled and evaluated for their use in simulating the effects of long-term conservation practices on agricultural ecosystems. The databases included a description of topography, climate, soil properties, agronomic and irrigation practices for characterization within the AnnAGNPS model.
Progress has been made on integrating the Lower Mississippi River Basin CEAP watershed long-term data sets into a common data management system the meets quality forms and standards. Long-term data sets from CEAP watersheds have been utilized to develop water budgets and provide information for LTAR network-wide projects.
Accomplishments
1. Models help estimate impacts of conservation practices on climate change. Climate change is projected to impact nutrient and sediment runoff from fields in the Mississippi Delta. Increased agricultural pollutants can produce problems for water resources and ecosystems. ARS researchers at Oxford, Mississippi, used projected climate data to evaluate potential impacts on nutrient and sediment runoff in the Beasley Lake watershed using the USDA Annualized Agricultural Non-Point Source (AnnAGNPS) pollution model. Simulation results indicated reduced expected runoff but increases in sediment and nutrient loads due to more intense storms. Conservation practices showed potential for reducing sediment and nutrient loads by 20 – 75% below historical levels, thus decreasing the impact of climate change for Mississippi Delta farmers. The implication for National Resources Conversation Service or state agency resource managers is that an investment in wider application of conservation practices may pay additional future dividends for improving water quality and ecosystems.
2. Vegetated drainage ditches and retention ponds mitigate contaminants. An improved understanding of how best to use combined agricultural best management practices (BMPs) to reduce suspended solids and nutrient loads and improve water quality is needed in intensive agricultural areas. ARS researchers at Oxford, Mississippi, collected runoff measurements of sediment, nitrogen, and phosphorus draining through vegetated drainage ditches into a vegetated sediment pond from crop-cultivated areas as part of the Conservation Evaluation Assessment Program watershed in the Mississippi Delta from 2011 to 2014. Vegetated drainage ditches combined with a vegetated sediment pond were effective in reducing sediment loads and moderately effective at reducing nutrient loads in runoff. As a result, the water quality of agricultural runoff was improved. Study results provide regulatory and other agencies and farming stakeholders with practical ways to improve and sustain water quality and overall environmental quality using combined conservation practices.
3. Glyphosate-resistant crops affect microbial soil community. Planting genetically-engineered corn to resist applications of the herbicide glyphosate in fields to control weeds has become a wide-spread management practice for implementing reduced tillage across the USA. ARS researchers at Oxford, Mississippi, designed and implemented a seven year-long field experiment in the Mississippi Delta to determine if this management practice would affect the process of nitrification, the microbial process converting ammonia to nitrate, and the soil microbial communities that initiate the process. Results of this study indicated that glyphosate applications appeared to inhibit nitrification in both bulk and rhizosphere soil environments. Continuous long-term applications of glyphosate to control weeds appeared to affect this naturally occurring microbial community. These results indicated that glyphosate may suppress the important soil nitrification process under both conventional tillage and no-till.
Review Publications
Omer, A.R., Miranda, L.E., Moore, M.T., Krutz, L.J., Prince-Czarnecki, J.M., Kroger, R., Baker, B.H., Hogue, J., Allen, P.J. 2018. Reduction of solids and nutrient loss from agricultural land by tailwater recovery systems. Journal of Soil and Water Conservation. 73(3):282-295. https://doi.org/10.2489/jswc.73.3.284.
Lizotte Jr, R.E., Locke, M.A. 2018. Assessment of runoff water quality for an integrated best-management practice system in an agricultural watershed. Journal of Soil and Water Conservation. 73(3):245-254.
Taylor, J.M., Back, J.A., Brooks, B.W., King, R.S. 2018. Spatial, temporal, and experimental: three study-design cornerstones for establishing defensible numeric criteria for freshwater ecosystems. Journal of Applied Ecology. https://doi.org/10.1111/1365-2664.13150.
Yasarer, L.M., Bingner, R.L., Momm, H.G. 2018. Characterizing ponds in watershed simulations and evaluating their influence on streamflowin a Mississippi Watershed. Hydrological Sciences Journal. 63(2):302-311. https://doi.org/10.1080/02626667.2018.1425954.
Moore, M.T., Locke, M.A. 2018. Can rice (Oryza Sativa) mitigate pesticides and nutrients in agricultural runoff. Bulletin of Environmental Contamination and Toxicology. 100(1):162-166. https://doi.org/10.1007/s00128-017-2225-0.
Alsharekh, A., Swatzell, L.J., Moore, M.T. 2018. Leaf composition of American bur-reed (Sparganium americanum Nutt.) to determine pesticide mitigation capability. Bulletin of Environmental Contamination and Toxicology. 100(4):576-580. https://doi.org/10.1007/s00128-018-2298-4.
Moore, M.T., Locke, M.A., Jenkins, M., Steinriede Jr, R.W., McChesney, D.S. 2017. Dredging effects on selected nutrient concentrations and ecoenzymatic activity in two drainage ditch sediments in the lower Mississippi River Valley. International Soil and Water Conservation Research. 5:190-195. http://doi.org/10.1016/j.iswcr.2017.06.004.
Omer, A.R., Moore, M.T., Krutz, L., Kroger, R., Prince-Czarnecki, J.M., Baker, B., Allen, P.J. 2017. Representation of solid and nutrient concentrations in irrigation water from tailwater recovery systems by surface water grab samples. Journal of Irrigation and Drainage Engineering. 143(11):06017013. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001234.
Faust, D.R., Kroger, R., Omer, A.R., Hogue, J., Baker, B., Prince-Czarnecki, J.M., Moore, M.T., Rush, S.A. 2018. Nitrogen and organic carbon contents of agricultural drainage ditches of the Lower Mississippi Alluvial Valley. Journal of Soil and Water Conservation. 73(2):179-188. http://doi.org/10.2489/jswc.73.2.179.
Taylor, J.M., Lizotte Jr, R.E., Testa III, S., Dillard, K.R. 2017. Source, habitat and nutrient enrichment effects on decomposition of detritus in Lower Mississippi River Basin bayous. Freshwater Science. 36(4):713-725. http://doi.org/10.1086/694452.
Vanni, M.J., McIntyre, P.B., Arnott, D.P., Benstead, J.P., Berg, D.J., Brabrand, A., Sebastien, B., Bukaveckas, P.A., Caliman, A., Capps, K.A., Carneiro, L.S., Chadwick, N.E., Christian, A.D., Clarke, A., Conroy, J.D., Culver, D.A., Dalton, C.M., Devine, J.A., Domine, L.M., Evans-White, M.A., Faafeng, B., Flecker, A.S., Gido, K.B., Godinot, C., Guariento, R., Haertel-Borer, S., Hall, R.O., Henry, R., Herwig, B.R., Hicks, B.J., Higgins, K.A., Hood, J.M., Hopton, M.E., Ikeda, T., James, W.F., Jansen, H.M., Johnson, C.R., Koch, B.J., Lamberti, G.A., Lessard-Pilon, S., Maerz, J.C., Mather, M.E., McManamay, R.A., Milanovich, J.R., Morgan, D.K., Moslemi, J.M., Naddafi, R., Nilssen, J., Pagano, M., Pilati, A., Post, D.M., Roopin, M., Rugenski, A.T., Schaus, M.H., Shostell, J., Small, G.E., Solomon, C.T., Sterrett, S.C., Strand, O., Tarvainen, M., Taylor, J.M., Torres-Gerald, L.E., Turner, C.B., Urabe, J., Uye, S., Ventela, A., Villeger, S., Whiles, M.R., Wilhelm, F.M., Wilson, H.F., Xenopoulos, M.A., Zimmer, K.D. 2017. A global database of nitrogen and phosphorus excretion rates of aquatic animals. Ecology. 98(5):1475.
Yasarer, L.M., Bingner, R.L., Garbrecht, J.D., Locke, M.A., Lizotte Jr, R.E., Momm, H.G., Busteed, P.R. 2017. Climate change impacts on runoff, sediment, and nutrient loads in an agricultural watershed in the Lower Mississippi River Basin. Applied Engineering in Agriculture. 33(3):379-392.
Spiegal, S.A., Bestelmeyer, B.T., Archer, D.W., Augustine, D.J., Boughton, E., Boughton, R., Clark, P., Derner, J.D., Duncan, E.W., Cavigelli, M.A., Hapeman, C.J., Harmel, R.D., Heilman, P., Holly, M.A., Huggins, D.R., King, K.W., Kleinman, P.J., Liebig, M.A., Locke, M.A., McCarty, G.W., Millar, N., Mirsky, S.B., Moorman, T.B., Pierson, F.B., Rigby, J.R., Robertson, G., Steiner, J.L., Strickland, T.C., Swain, H., Wienhold, B.J., Wulfhorts, J., Yost, M., Walthall, C.L. 2018. Evaluating strategies for sustainable intensification of U.S. agriculture through the Long-Term Agroecosystem Research network. Environmental Research Letters. 13(3):034031. https://doi.org/10.1088/1748-9326/aaa779.
CJenkins, M., Locke, M.A., Reddy, K.N., McChesney, D.S., Steinriede Jr, R.W. 2018. Glyphosate applications, glyphosate resistant corn, and tillage on nitrification rates and distribution of nitrifying microbial communities. Soil Science Society of America Journal. 81(6):1371-1380.
