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Stream water concentrations of herbicides and nutrients for sites in the northern Missouri and southern Iowa region, 1994 to 1999

posted on 2023-11-30, 08:39 authored by Robert Lerch

The data set contains stream water concentrations of herbicides and nutrients for 153 sites in the northern Missouri/southern Iowa region from 1994 to 1995. The data are available in Microsoft Excel 2010 format. Sheet 1 (Metadata) of the file contains supporting information regarding the length of record, site locations, parameters measured, concentrations units, method detection limits, describes the meaning of zero and blank cells, defines the major land resource areas (MLRAs) of the region, and provides a link to the U. S. Geological Survey discharge data. Sheet 2 (Site names and locations) has a list of the site names by MLRA, river system, and site name. It also contains site locations, provided as Universal Transverse Mercator coordinates, drainage areas, and indicates which sites were co-located at U. S. Geological Survey gauge sites. Sheet 3 (Concentration Data) contains data for 15 herbicide and nutrient analytes along with the corresponding site name, river system, and MLRA. Atrazine concentrations in Goodwater Creek Experimental Watershed (GCEW) were shown to be among the very highest of any watershed in the United States based on comparisons using the national Watershed Regressions for Pesticides (WARP) model and by direct comparison with the 112 watersheds used in the development of WARP. The herbicide data collected in GCEW are documented at plot, field, and watershed scales. This 20-yr-long (1991-2010) effort was augmented with a spatially broad effort within the Central Mississippi River Basin encompassing 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 northern Missouri and southern Iowa. The research effort on herbicide transport has highlighted the importance of restrictive soil layers with smectitic mineralogy to the risk of transport vulnerability. Near-surface soil features, such as claypans and argillic horizons, result in greater herbicide transport than soils with high saturated hydraulic conductivities and low smectitic clay content.

Resources in this dataset:


Agricultural Research Service


Data contact name

Lerch, Robert

Data contact email


Journal of Environmental Quality

Intended use

Nitrogen (N) and phosphorus (P) pollution of water resources has been a major environmental problem for decades, resulting in contaminated water supplies, detrimental effects on aquatic and human health, impaired recreational water quality, and formation of the hypoxic zone in the Gulf of Mexico. At field and plot scales, studies were designed to assess the impact of specific crop management practices, the overall effect of cropping systems, and the variation in soil properties at the landscape scale on N and P transport in surface runoff and to the shallow loess and glacial till aquifers of claypan soils. A key finding of these studies was that field areas with the poorest crop growth were also the most vulnerable to nutrient as well as sediment and herbicide transport. The datasets generated in the 20-yr-long (1991-2010) research effort are documented to study the transport of herbicides to surface and groundwater in the GCEW. A key finding was that near-surface restrictive soil layers, such as argillic horizons of smectitic mineralogy, result in greater herbicide transport than soils with high percolation and low clay content. Because of this, streams in the claypan soil watersheds of northeastern Missouri have exceptionally high herbicide concentrations and relative loads compared with other areas of the Corn Belt.

Use limitations

Quality assurance (QA) samples were incorporated as part of all field studies and included duplicate, spike, and blank samples. If acceptable duplicate precision was not obtained after several tries, data from the most precise pair were reported and flagged. In many cases, samples were reanalyzed and the QA criteria were met. If the results were unacceptable after reanalysis, the data were not included in the Sustaining the Earth's Watersheds: Agricultural Research Data System (STEWARDS) database.

Temporal Extent Start Date


Temporal Extent End Date



  • Not specified

Geographic Coverage


ISO Topic Category

  • environment
  • farming

Ag Data Commons Group

  • Central Mississippi River Basin
  • Long-Term Agroecosystem Research

National Agricultural Library Thesaurus terms

streams; herbicides; nutrients; rivers; drainage; atrazine; watersheds; models; Mississippi River; mineralogy; argillic horizons; clay fraction; nitrogen; phosphorus; water pollution; water supply; human health; water quality; cropping systems; soil properties; landscapes; runoff; loess; aquifers; claypan soils; sediments; groundwater; Corn Belt region

OMB Bureau Code

  • 005:18 - Agricultural Research Service

OMB Program Code

  • 005:040 - National Research

Pending citation

  • No

Public Access Level

  • Public

Preferred dataset citation

Lerch, Robert (2020). Stream water concentrations of herbicides and nutrients for sites in the northern Missouri and southern Iowa region, 1994 to 1999. Journal of Environmental Quality.