Table of Contents (annotated to explain supplemental online materials and provide links to documents)
Sadler, E.J., R.N. Lerch, N.R. Kitchen, S.H. Anderson, C. Baffaut, K.A. Sudduth, A.A. Prato, R.J. Kremer, E.D. Vories, D.B. Myers, R. Broz, R.J. Miles, and F.J. Young. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Introduction, establishment, and overview. J. Environ. Qual. 44:3-12.
The main paper includes a discussion about long-term environmental data and its increasing relevance to science, a history of the ARS watershed program, the establishment of GCEW, introduces the special section, and identifies research gaps with potential to increase relevance and impact of the database.
Supplement 1 includes lists of references relevant to specific sections of the main paper, plus an explanation of geospatial data available to support the time series data in STEWARDS.
Supplement 2 includes a comprehensive discussion of the geomorphic development of the soils in the region and a description of the anthropogenic changes to the landscape since the 1800's.
Supplement 3 comprises a brief annotated bibliography of research conducted with the data and in the region.
Sadler, E.J., K.A. Sudduth, S.T. Drummond, E.D. Vories, and P.E. Guinan. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed weather data. J. Environ. Qual. 44:13-17.
The main paper describes the installation and operation of the weather instrumentation, describes quality assurance procedures, briefly describes some extremes and averages, outlines availability and access to STEWARDS, and reviews research that has been conducted with the data.
Supplement 1 gives details of the weather instruments, provides lists of nearby weather data resources for cross-site comparisons, describes retrospective quality assurance steps, presents comparisons to data from nearby stations, provides long-term statistical descriptions, and describes the metadata and STEWARDS access.
Baffaut, C., E.J. Sadler, and F. Ghidey. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed flow data. J. Environ. Qual. 44:18-27.
The main paper describes the discharge monitoring sites and the data collection methods. It documents the data available at three scales: plot, edge-of-field, and streams. It provides the main characteristics of discharge at these sites.
Supplement 1 describes the equipment used at the discharge monitoring sites, provides details on the construction of the wing walls at the bottom of the plots, gives the equation for Parshall flumes in metric units, gives stream and weir cross-sections for two stream weirs, the existing Young's Creek measurements, presents flow metadata, and describes plot and field management necessary to interpret the discharge data.
Lerch, R.N., C. Baffaut, E.J. Sadler, and R.J. Kremer. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed and regional herbicide water quality data. J. Environ. Qual. 44:28-36.
The main paper provides an overview of the data collected in the 20-year long research effort to study the transport of herbicides to surface and ground waters and includes descriptions of analytical methods, study locations, periods of record, and means of accessing the data.
Supplement 1 contains analytical methods, quality assurance procedures, and the navigation aid for STEWARDS.
Also available under the 'download' section are two spreadsheets containing water quality data relevant to the GCEW, but external to the STEWARDS database.
Dataset 1 contains herbicide, nutrient, and suspended sediment concentration, load, and daily discharge data for 14 water quality parameters in the Devils Icebox and Hunters Caves streams from 1999 to 2002 (~4.4 MB).
Dataset 2 contains stream water concentrations of herbicides and nutrients for 153 sites in the northern Missouri/southern Iowa region from 1994 to 1995 and additional data from 1996 to 1999 for 21 sites (~600 kB).
Lerch, R. N., N.R. Kitchen, C. Baffaut, and E.D. Vories. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed and regional nutrient water quality data. J. Environ. Qual. 44:37-43.
The main paper provides an overview of the data collected as part of the long-term research effort to study the transport of nutrients to surface and ground waters and includes descriptions of analytical methods, study locations, periods of record, and means of accessing the data.
Supplement 1 contains analytical methods for nutrients, the navigational aid for STEWARDS, a table of the nutrient compounds analyzed by site and period of record, and a table of groundwater well depths and locations.
Lerch, R.N., C. Baffaut, N.R. Kitchen, K.A. Sudduth, and E.J. Sadler. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Dissolved nitrogen and phosphorus transport in a high runoff potential watershed. J. Environ. Qual. 44:44-57.
The main paper includes detailed analyses of long-term trends in nutrient transport, land use, and fertilizer inputs in Goodwater Creek Experimental watershed demonstrated the water quality benefits associated with shifting fertilizer application from fall to spring.
Supplement 1 contains a detailed description of how concentrations were interpolated in time to preserve the mass balance, an explanation of land-use changes and fertilizer inputs, flow-weighted concentrations and loads (STEWARDS contains the raw data but not these derived products), and tables of distributions of nutrients by year.
Kitchen, N.R., P.E. Blanchard, and R.N. Lerch. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Hydrogeologic controls and crop management influence on nitrates in loess and fractured glacial till. J. Environ. Qual. 44:58-70.
The main paper documents a long-term investigation on the interactions and complexities that exist when considering the effects of spatially-heterogeneous glacial-till hydrogeology, ground water geochemistry, and crop management on ground water nitrate concentrations.
Sudduth, K.A., G. Jang, R.N. Lerch, and E.J. Sadler. 2015. Long-term agro-ecosystem research in the Central Mississippi River Basin: Hyperspectral remote sensing of reservoir water quality. J. Environ. Qual. 44:71-83.
The main paper compares three methods of determining the water quality in Mark Twain Lake. Both proximal and aircraft hyperspectral observations were compared with direct sampling and laboratory analysis. Remote sensing methods provided good results when calibration relationships were established using water samples obtained on the same date.
Baffaut, C., F. Ghidey, E.J. Sadler, and S.H. Anderson. 2015. Long-term agro-ecosystem research in the central Mississippi River Basin: SWAT simulation of flow and water quality in the Goodwater Creek Experimental Watershed. J. Environ. Qual. 44:84-96.
The main paper describes how the SWAT model was parameterized to simulate flow and sediment, atrazine, and dissolved phosphorus transport. It proposes two novel changes into the model: 1) an alternate method to simulate percolation through the claypan and saturation above this restrictive layer and 2) an algorithm to simulate the spatial and temporal distribution of the timing of field operation in the watershed.
Supplement 1 details field operations used in the model for the different crops and management systems, describes land use and land management distribution in the watershed and in the model, lists sensitive parameters of the model, details the simulated effects of operation scheduling, and details the simulated effects of two management practices aimed at reducing atrazine transport.
Supplement 2 gives the full report of the survey of management and conservation practices adopted by farm operators in the watershed in 2006, which was used to guide the parameterization of the model.
Prior articles critical to users of these data:
Baffaut, C., Ghidey, F., Sudduth, K. A., Lerch, R. N., and Sadler, E. J. Long-term suspended sediment transport in the Goodwater Creek Experimental Watershed and Salt River Basin, Missouri, USA. Water Resour. Res., 49, doi:10.1002/wrcr.20511. 2013. (link)
Baffaut, C., Sadler, E. J., and Ghidey, F. A methodology to reduce uncertainties in the high-flow portion of a rating curve. Trans. ASABE 57:803-813. (link)
Lerch, R. N., Sadler, E. J., Kitchen N. R., Sudduth, K. A., Kremer, R. J. Myers, D. B., Baffaut, C., Anderson, S. H., and Lin, C. H. Overview of the Mark Twain Lake/Salt River Basin conservation effects assessment project. J. Soil & Water Cons. 63(6):345-359. 2008. (link)
Kitchen, N. R., Sudduth, K. A., Myers, D. B., Massey, R. E., Sadler, E. J., Lerch, R. N., Hummel, J. W., and Palm, H. L. Development of a conservation-oriented precision agricultural system: Crop production assessment and plan implementation. J. of Soil & Water Cons. 60(6):421-430. 2005. (link)
Lerch, R. N., Kitchen, N. R., Kremer, R. J., Donald, W. J., Alberts, E. E., Sadler, E. J., Sudduth, K. A., Myers, D. B., and Ghidey, F. Development of a conservation-oriented precision agricultural system: Water and soil quality assessment. J. of Soil & Water Cons. 60(6):411-421. 2005. (Web of Science link)