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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #287199
Title: Long-term agroecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed and regional herbicide water quality data

Author
item Lerch, Robert
item Baffaut, Claire
item Sadler, Edward
item Kremer, Robert

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2014
Publication Date: 1/8/2015
Citation: Lerch, R.N., Baffaut, C., Sadler, E.J., Kremer, R.J. 2015. Long-term agroecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed and regional herbicide water quality data. Journal of Environmental Quality. 44:28-36. DOI: 10.2134/jeq2013.12.0516.

Interpretive Summary: The Cropping Systems and Water Quality Research Unit in Columbia, MO has conducted long-term research to assess the impact of row crop production and watershed factors on herbicide and nutrient contamination of streams in the Central Mississippi River Basin. Since 1991, Goodwater Creek Experimental Watershed (GCEW), an agricultural watershed dominated by claypan soils, has been the focus area of this work. This long-term effort has been enhanced with many additional sites within the Central Mississippi River Basin, including 12 related claypan watersheds in the Salt River basin, two cave streams on the fringe of the Central Claypan Areas in the Bonne Femme watershed, and 95 streams in the northern Missouri/southern Iowa region. Within GCEW, studies were conducted at field- and plot-scales to determine the effect of various cropping systems on herbicide and nutrient transport. Sampling techniques, analytical methods, site locations, and equipment infrastructure are described. Compounds routinely measured included seven commonly used soil-applied corn and soybean herbicides, six herbicide metabolites, and dissolved forms of nitrogen (nitrate and ammonium) and phosphorus (ortho-phosphate). From 1991 to 2010, 11,808 water samples were analyzed for herbicides or herbicide metabolites, and 13,675 water samples were analyzed for nitrogen and phosphorus. Concentrations of nutrient species in GCEW and northern Missouri streams were in the range associated with nuisance algal growth and presumed loss of aquatic invertebrate diversity. Herbicide transport among watersheds was related to the presence of restrictive soil layers, those with a high content of shrink-swell clays, which limit the downward movement of water through the soil profile. The claypan soil watersheds of northeastern Missouri were shown to have exceptionally high herbicide concentrations and relative loads compared to other areas of the Corn Belt. A key finding of the field-scale studies in GCEW was that field areas with poorest crop growth were also the most vulnerable to nutrient, sediment, and herbicide transport. Thus, the development of sustainable cropping systems on marginal cropland could improve profitability and environmental quality.

Technical Abstract: Goodwater Creek Experimental Watershed (GCEW) has been the focus area of a long-term effort to document the extent of and to understand the factors controlling herbicide and nutrient transport. This article documents the datasets generated in the 20-year long research effort to study the transport of herbicides, nitrogen (N), and phosphorus (P) to surface and ground waters in GCEW. It also documents related efforts in nearby claypan watersheds and watersheds with contrasting soil and hydrologic conditions across northern Missouri. A brief overview of analytical methods and study locations, along with published research supported by these datasets, are described.