Project : USDA ARS

ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Research Project #432224

Research Project: Long-term Management of Water Resources in the Central Mississippi River Basin

Location: Cropping Systems and Water Quality Research

2019 Annual Report

Objectives
Objective 1: Determine linkages between stream water quality and field characteristics through field and watershed scale studies. 1a: Improve the Phosphorus (P) Index on claypan soils. 1b: Determine nutrient fluxes from surface drained land in the lower Mississippi River basin. 1c: Assess stream water quality within the northern Missouri/southern Iowa Region (NMSIR). Objective 2: Assess the effectiveness of conservation practices to mitigate the impacts of agriculture on water quality in the Central Mississippi River Basin. 2a: Assess the effect of grasses and vegetative buffers on the fate of organic contaminants. 2b: Determine effectiveness of buffer strips, crop rotations and cover crops. Objective 3: As part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the Central Mississippi River Region, use the Goodwater Creek Experimental Watershed 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 Central Mississippi River basin. 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. 3a: Establish an observatory for weather and discharge monitoring representative of the CMRB. 3b: Establish and conduct an experiment comparing the performance of two farming systems: one business as usual (BAU) that reflects the dominant agricultural practices in the CMRB and one aspirational (ASP) that is hypothesized to result in less adverse environmental impacts and improved economic output. 3c: Investigate greenhouse gas (GHG) as a function of crops and top soil depth. 3d: Assess denitrification in claypan soils. 3e: Assess climate change impacts in CMRB.

Approach
Increased sustainability of agriculture in the Mississippi River Basin will be studied at field, farm, and watershed scales. This research will focus in understanding how alternative farming systems can become more resilient and sustainable through increased food production, less environmental impacts on water and air resources, and climate regulation. The overall goal of this project is to improve understanding of, and help manage water resources for sustainable agricultural production in the Central Mississippi River Basin (CMRB). Emphasis is given to long-term study, i.e., 50 year window. Thus, we will design and implement a monitoring infrastructure for this research. The project will focus on edge of field studies that link water quantity and quality to field characteristics, soil, crop and agronomic management practices, and conservation practices (e.g., buffer strips); on watershed studies that link inherent vulnerability caused by soils and topography to stream water quality; on regional studies that broaden the scope of our plot, field, and watershed research. The observatory of the Long-Term Agroecosystems Research (LTAR) infrastructure will provide long-term data of weather and stream flow in our research watershed to reveal possible manifestations of climate change, as well as interpret experimental observations and drive simulation models. The Common Experiment, within the LTAR project, will compare production, surface runoff quantity and quality, soil health, and biological indicators between “Business-As-Usual” (BAU) and Aspirational (ASP) systems and inform environmental (e.g., crop residue reducing soil erosion potential) and economic (e.g., crop yield and quality) aspects of relative sustainability of the two systems. Long-term assessment of water, carbon, and nutrient budgets will show how the respective components are affected by climate change and management. Measurement of instantaneous energy, water, and carbon fluxes will provide needed data for full interpretation of the differences observed between these management systems. Short term plot studies are included to investigate processes, including soil emissions of greenhouse gases and denitrification, where interaction between management (e.g., tillage, crop type, fertilizer) and soil landscape properties (e.g., landscape position, soil horizonation) may be a significant factor. These plot studies will provide guidance to design and implement the long-term nfrastructure.

Progress Report
Published a dataset, along with a data paper, which includes runoff, sediment and phosphorus loss from agricultural fields, along with management and soil characteristics. This data set is useful to evaluate phosphorus loss models and indices. (Obj. 1a). In collaboration with cooperator, completed the evaluation of the Natural Resources Conservation Service (NRCS) Soil Vulnerability Index (SVI), which classifies inherent soil vulnerability of cropland to loss of sediment and nutrients by runoff and leaching. Communicated our conclusions regarding the possible improvement of SVI to NRCS. These conclusions will be used in our improvement of the Phosphorus Index (Obj. 1a) and to link field characteristics to runoff and stream water quality. (Obj. 1b). The 2nd year of water quality monitoring in northern Missouri streams is near completion. All pre-plant samples were collected by the first week of April 2019. Post-plant sampling was delayed to due to high flow conditions and is currently underway. We expect sampling completion by the second week of July 2019. (Obj. 1c). Kinetic studies using 14C-atrazine showed that phytochemicals in root extracts of three different switchgrass varieties demonstrated atrazine degradation at slow, but steady rates. Detected a presumptive metabolite, which does not correspond to any known atrazine metabolite. Calcium saturated montmorillonite has been prepared and sufficient DIBOA-glucoside (DBG) standard, a chemical produced by plants to defend themselves against harmful compounds, has been purified for studies about the sorption of DBG to purified montmorillonite and to field soils. (Obj. 2a). Methods for soil extraction and analysis of veterinary antibiotics and estrogenic compounds have been developed and validated. Initiated degradation studies of the veterinary antibiotics and estrogenic compounds in June 2019. (Obj. 2a). Completed and published manuscript that analyzed flow and water quality from systems with and without cover crops based on the 1997-2002 data (Obj. 2b). Meanwhile, implementation of Long-Term Agroecosystem Research (LTAR) cropping systems and plant, soil, water, and air sampling are ongoing at three scales: small plots, large plots, and fields (Obj. 2b, 3a, 3b). The replacement of pressure transducers by flow bubblers has progressed, with eight plots equipped with these. An additional 10 flow bubblers will be installed in late FY19 or early FY20. (Obj. 2b, 3a, and 3b). The 2017 flow and water quality data at the plot scale are certified. Weather, flow, and water quality data at field and stream sites through 2017 were uploaded in Sustaining the Earth's Watersheds, Agricultural Research Data System (STEWARDS) by Q1 of FY2019 per STEWARDS protocol (Obj. 3a). Data for 2018 are proceeding through quality analysis per established procedures. Flow data and samples from 2019 are being collected and analyzed. Data management is progressing to ensure data quality, security, and accessibility. Current weather data from the Central Mississippi River Basin are uploaded to the National Agricultural Library on an hourly basis. Developed programs for early warnings of failing plot monitoring infrastructure or data transfer. The unit data store is being transferred from a leased tablespace to a stand-alone relational database management system (SQL Server), managed in-house. Flow and rainfall have been ported and access programs revised; remainder of current data, including water quality, will be ported by end of FY2019; established data structures and import & export applications for more comprehensive weather station data (Obj. 3a). Energy, carbon, and water vapor flux data are available pending post-processing (Obj 3b). Data exist from the aspirational management field (established 6/2015), the business-as-usual field (6/2016), reference native prairie (10/2017) sites, and Missouri Ozarks AmeriFlux (MOFLUX – established 2002) site as another, forested, reference. Prototyped the Max Planck Institute REddyProc package and coordinate rotation into our internal data workflow and our database structure as derived products, and followed procedures and assumptions accepted in the Ameriflux network. Cooperator conducted a test of self-heating in response to flux community concerns for open-path infrared gas analyzers (IRGA). Formalized and documented the seasonal calibration procedure and fabricated a calibration stand to reduce operator-induced variation and error. Production and associated management data have been collected and certified for aspirational and business-as-usual cropping systems, at the field and plot scales. A cooperator has collected and is analyzing data collected through the growing season from an unmanned aerial vehicle (UAV, aka drone). Preliminary on-combine sensor measurements of grain quality have been obtained at the plot and field scale, with the potential of comparing quality as well as yield between the aspirational and business-as-usual sites. Consistent with LTAR network expectations, both the aspirational and business-as-usual systems are being reviewed to insure they are still our best estimates of current and aspirational practices in the region. (Obj. 3b). Samples for which we did not receive any data last year have been reprocessed in-house. Soil analysis for comparison of the structural and functional biodiversity of the microbial community is now complete. Data analysis is underway. A paper on water budgets across the LTAR network is near completion and will be submitted by the end of FY19. (Obj. 3b). Following the resolution of previous problems with gas chromatography instrument, a number of sets of samples were successfully analyzed in 2018, which provided confidence in the data. Meanwhile the aspirational and business-as-usual cropping systems had been implemented on plots and GHG sampling was initiated at the end of March 2019. GHG samples are currently collected weekly and after major rain events. A soil oxygen sensor was installed at the site to better inform timing of anoxic conditions. We expect a complete and valid data set for FY19. (Obj. 3c). Analysis of grid samples for denitrification potential is near completion. This dataset will allow for analysis of the spatial dependence of denitrification. In combination with the soil cores (see below), these data should help to identify “hot spots” for denitrification in these fields. A third year of soil oxygen, temperature, and moisture are being collected at three landscape positions in the aspirational and business-as-usual fields. Soil cores collected from both fields were sent to the Carey Institute of Ecosystem Studies for determination of total denitrification. Data for three of five sets of cores has been delivered, but there was an error in the computations and the data need correction. Once these data are finalized, field-scale estimates of denitrification rates can be developed. In addition, soil RNA and DNA work has been performed on the top soil for the core transects (cores were collected in duplicate) in an effort to quantify key genes in the denitrification pathway. Comparison of genetic techniques for quantification of denitrification enzymes was performed, and the first known quantification of denitrification genes using RNA techniques is near completion. (Obj. 3d). Work under the Non-Assistance Cooperative Agreement (NACA) implemented to assess water availability and productivity in the Goodwater Creek Experimental and Mark Twain Lake watersheds under varying climate (Obj. 3e) is nearly complete. A manuscript on water availability in Mark Twain Lake watershed has been accepted. A second manuscript on the balance between future water demand and availability is 50% completed.

Accomplishments
1. Runoff water quality from a 3-year no-till grain system with cover crops is better than from a 2-year no-till system. Short-term monitoring studies have shown that a no-till corn-soybean system on claypan soils reduces sediment losses but does not reduce runoff compared to a mulch-tilled system. It can double or triple the transport of non-incorporated chemicals, such as herbicides and dissolved phosphorus. However, long-terms effects of these systems remained in question. The Agricultural Policy/Environmental Extender (APEX) model was used to simulate runoff and loss of atrazine and nutrients from grain cropping systems over a 14-year period. Five years of flow and water quality monitoring data and 14 years of yield data provided the basis for parameter adjustment. The results confirmed that the cropping systems did not affect runoff volume. The 3-year no-till corn-soybean-wheat with cover crops was better for runoff water quality than a no-till 2-year corn-soybean system without cover crops. It appears to mitigate negative effects of no-till on the surface transport of non-incorporated dissolved chemicals. Explanations included the beneficial fertilizer and herbicide management (rate, placement, and timing) as well as the possible reduction of nitrate leaching by cover crops. The results are useful for producers and conservation managers by providing long-term impacts of grain cropping systems on water quality.

2. Published PLEAD: the Phosphorus Loss in runoff Events from Agricultural fields Database. Computer models used to predict risks of runoff phosphorus (P) loss require runoff and water quality data for evaluating their accuracy. A complicating factor is the lack of data with and without conservation practices under diverse soil and climate conditions. ARS researchers at Columbia, Missouri; University Park, Pennsylvania; Bowling Green, Kentucky; and university collaborators have published the P Loss in runoff Events from Agricultural Fields (PLEAD) database, which includes > 1800 runoff events from various sites in the U.S. This database provides public access to P loss data for individual runoff events, along with associated soil, topography, weather, and land management information. The PLEAD data have been used for model performance evaluation and can be used by other researchers to evaluate other P loss models or P indices. Having a common database to test model performance is important to water resource managers that rely on these tools to assess conservation scenarios.

3. Documented the publication of guidelines for calibrating hydrologic models. Hydrologic and water quality simulation models include a suite of mathematical equations that represent landscape and stream processes. Use of these models for specific studies should follow documented methods in order to ensure correct outcomes. Yet, modelers commonly use arbitrary, ad-hoc methods to conduct, document, and report model calibration, validation, and evaluation. ARS researchers in Columbia, Missouri, and Fort Collins, Colorado, documented the process by which multiple scientists developed guidelines for the calibration and validation process. These guidelines establish consistent terminology and definitions, and detail the numerous steps necessary to ensure sound model development and meaningful results. The documentation of the guideline development process provides additional exposure to the guidelines and ensures that they are easily accessible by modelers and decision-makers who use modeling results.

4. Evaluated four parameterization strategies for the Agricultural Policy/Environmental Extender (APEX). Most complex hydrological models require the determination of input parameters by adjusting these parameter values until model results match observed data. When edge-of-field runoff and water quality data are not available, modelers rely on best professional judgement or on parameter sets obtained for similar watersheds. But is that acceptable? ARS researchers at Columbia, Missouri, in collaboration with University of Missouri and Kansas State University partners have tested the performance of parameter sets obtained through calibration on watersheds different from the test watershed on which they were evaluated. They found that only the parameter sets that met performance criteria based on runoff, sediment, and total phosphorus on the calibration watershed met the performance criteria on the test watershed. These parameter sets produced similar responses for conservation scenarios. For parameter sets that did not meet performance criteria based on runoff, sediment, and total phosphorus, the conservation outcomes were sometimes different, which could be misleading. The information is useful to researchers and water resource managers that rely on models to assess conservation scenarios.

5. Documented contrasting ecosystems’ responses to a total solar eclipse. The 2017 total solar eclipse offered a rare opportunity to examine numerous aspects of a precipitous change in near-noon solar radiation in the absence of other gradual atmospheric changes that occur during the dawn and dusk transition periods. ARS researchers in Columbia, Missouri, in collaboration with multiple university colleagues, obtained high-frequency data for several days either side and on the day of the eclipse from three eddy covariance flux towers sited in a forest, prairie, and cropland field (soybeans). With the cessation of solar radiation, which is the driving force, evaporation essentially stopped. Sensible heat flux actually reversed, resulting in heating of the ecosystems by the atmosphere during the totality period. The data set obtained could be used to test models that simulate energy and water movement at the soil-atmosphere boundary, which is a necessary step toward the improvement of these models.

6. Improved soil health assessment for producers. Conservation management practices have been shown to improve soil health measurements that are indicators of environmental benefits, yet the sensitivity and utility of soil health measurements have not been adequately determined. ARS researchers at Columbia, Missouri, in collaboration with scientists from the University of Missouri, evaluated multiple biological and physical soil health indicators in Midwestern perennial and row cropped systems. Microbial biomass, microbial activity, and soil thermal properties were shown to be sensitive to tillage and cover cropping practices in corn-soybean rotation. Microbial soil health indicators were also found to be sensitive to sample handling conditions. Overall, perennial systems demonstrated improved soil health over annual cropping systems. These results illustrate the need for standardized sampling and handling protocols and highlight the potential utility of multiple soil health indicators. This information benefits producers by providing a better understanding of indicators for soil health assessment and aids in making more informed management decisions.

U.S. DEPARTMENT OF AGRICULTURE

Cropping Systems and Water Quality Research: Columbia, MO