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M.K. Landon

Publications and source records attributed to M.K. Landon.

24 records · Page 2Linked to original sources
USGS1994

Hydrogeologic and water-quality data used to characterize the Management Systems Evaluation Area near Princeton, Minnesota, 1991

The Minnesota Management Systems Evaluation Area project is part of a multi-scale, inter-agency initiative to evaluate the effects of agricultural management systems on water quality in the midwest corn belt. The research area is located in the Anoka Sand Plain about 5 kilometers southwest of Princeton, Minnesota. The ground-water-quality monitoring network within and immediately surrounding the research area consists of 29 observation wells and 22 multiport wells. Thirteen observation wells are also located outside the research area. The primary objectives of research by the U.S. Geological Survey at the Princeton Management Systems Evaluation Area are to: (1) determine the relation of the spatial and temporal distribution of agricultural chemicals in ground water to recharge, topography, and subsurface heterogeneities; and (2) determine the effects of the modified and prevailing farming systems on ground-water quality. This report presents geologic logs and water-quality data used to characterize the Princeton Management Systems Evaluation Area.

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USGS1994

Characterization of the hydrogeology and water quality at the Management Systems Evaluation Area near Princeton, Minnesota, 1991-92

The Management Systems Evaluation Area (MSEA) program is part of a multi-scale, inter-agency initiative to evaluate the effects of agricultural management systems on water quality in the midwest corn belt. The Minnesota MSEA project is one of five projects selected to represent the principal hydrogeologic settings and geographic diversity of prevailing management systems in the midwest corn belt. The Minnesota MSEA research area is located in the Anoka Sand Plain about 5 kilometers southwest of Princeton, Minnesota. The water-quality monitoring network within the 65-hectare research area consists of 29 observation wells and 22 multiport wells. Thirteen observation wells also are located outside the research area. Glacial deposits beneath the research area generally consist of fine to medium sand in the unsaturated zone and coarse to very coarse sand and gravel in the saturated zone. The average depth to the water table is about 3.6 meters below land surface. Ground-water recharge during 1992 was lower (4.9-13.2 centimeters) than during 1991 (11.7-25.7 centimeters) because of reduced precipitation (58.5 centimeters during 1992 and 94.5 centimeters during 1991). Estimates of saturated horizontal hydraulic conductivity for the surficial aquifer were made using five methods. Results were within about two orders of magnitude and also agree favorably with estimates from a previous study of the Anoka Sand Plain. The smallest hydraulic conductivities were obtained using laboratory analyses (0.0052 centimeters per second) and the largest estimate was obtained from results of an aquifer test (0.2820 centimeters per second). The estimate of hydraulic conductivity based on the time of travel of chloride (0.0655 centimeters per second) is considered most accurate and representative of the surficial aquifer in the research area. Anthropogenic effects of previous land use were detected in water samples collected during April 1991, prior to implementation of the MSEA farming systems. Concentrations of nitrate-nitrogen (nitrate-N) in the surficial aquifer equaled or exceeded the U.S. Environmental Protection Agency's recommended maximum contaminant level of 10 milligrams per liter (mg/L) in 4 of the 7 wells in the research area. The maximum concentration of nitrate-N in ground water from these wells was 23 mg/L with a median of 10 mg/L. The median concentration of nitrate-N for these wells exceeded the median in wells located upgradient from the research area (2.1 mg/L). Similarly, the median concentration of chloride from wells in the research area (11 mg/L) exceeded the median in upgradient wells (3.8 mg/L). On-site sources of the elevated nitrate-N include decomposition of alfalfa, grown on-site during 1981-89, and application of nitrogen fertilizer to corn during 1990. A likely on-site source of the elevated chloride is application of potassium-chloride fertilizer to crops prior to 1991. Atrazine was detected by gas chromatography mass spectroscopy in 2 of the 7 wells in the research area at concentrations of 0.04 and 0.17 micrograms per liter (ug/L), well below the U.S. Environmental Protection Agency's recommended maximum contaminant level of 3 ug/L. The median concentration in these Wells was less than the qualitative detection limit of 0.01 ug/L. Atrazine metabolite de-ethylatrazine was the most frequently detected herbicide or herbicide metabolite. De-ethylatrazine was detected in 5 of the 7 wells in the research area at concentrations ranging from 0.12 to 0.32 ug/L with a median concentration of 0.14 ug/L. Atrazine metabolite de-isopropylatrazine was not detected above the qualitative detection limit of 0.06 ug/L. The most likely sources of atrazine are applications to the research area during 1990 or from precipitation.

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USGS1993

Effects of focused recharge on the transport of agricultural chemicals at the Princeton, Minnesota Management Systems Evaluation Area, 1991-92

Rates of water movement through the unsaturated zone greatly affect the amount and concentrations of agricultural chemicals that may reach the water table. For example, recharge can flush chemicals to the water table which have accumulated in the unsaturated zone during dry periods. A better understanding of how topography influences recharge and the movement of agricultural chemicals is needed. In 1991, the U.S. Geological Survey (USGS), with funding from the USGS Toxic Substances Hydrology Program, began studying the movement of water and agricultural chemicals to the water table at the Management Systems Evaluation Area (MSEA) near Princeton, Minnesota. The primary objective of this four-year research study is to evaluate the effects of transient recharge, topography, and subsurface heterogeneities on the flux of water and agricultural chemicals to ground water. To achieve this objective the approach was to (1) install instruments to sample and measure the movement of water through the unsaturated zone beneath topographically high and low areas of a corn field; (2) conduct recharge and tracer tests in the field to evaluate the movement of water and agricultural chemicals at both topographic settings; and (3) simulate the field recharge and tracer tests in the laboratory. The primary research hypothesis was that the vertical flux of water and agricultural chemicals is greater in topographically low areas than in topographically high areas.

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USGS1993

Effects of recharge on the transport of agricultural chemicals at the Princeton, Minn. Management Systems Evaluation Area (MSEA), 1991-92

Rates of water movement through the unsaturated zone greatly affect the amount and concentrations of agricultural chemicals that may reach the water table. For example, recharge can flush to the water table chemicals that have accumulated In the unsaturated zone during dry periods. A better understanding of how topography influences recharge and the movement of agricultural chemicals is needed. In 1991, the U.S. Geological Survey (USGS), with funding from the USGS Toxic Substances Hydrology Program, began studying the movement of water and agricultural chemicals to the water table at the Management Systems Evaluation Area (MSEA) near Princeton, Minnesota. Instruments were installed to measure the movement of moisture through the soil beneath a corn field. Samples of the recharge water were analyzed for concentrations of agricultural chemicals and tracers. Field recharge and tracer tests were simulated In the laboratory.

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USGS1992

Hydrologic research at the Princeton, Minnesota management systems evaluation area

The Management Systems Evaluation Area (MSEA) program is part of a multi-scale, inter-agency initiative to evaluate the effects of agricultural management systems on water quality. The program resulted from the integration of the U.S. Department of Agriculture (USDA) Research Plan for Water Quality and the U.S Geological Survey (USGS) Mid-Continent Herbicide Initiative and is part of the President's Water Quality Initiative. The mid-continental corn belt was selected for study because it is an area where about 60% of the Nation's pesticides and nitrogen fertilizers are used.

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