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Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River basin. Noncontrollable factors such as precipitation and mineralization of soil organic matter have a tremendous effect on drainage losses, nitrate concentrations, and nitrate loadings in(More)
Agricultural losses of phosphorus (P) in runoff are a primary cause of eutrophication in many freshwater systems. A modified version of the P Index originally developed jointly by the USDA (Agricultural Research Service [ARS], Cooperative State Research, Education, and Extension Service [CSREES], and Natural Resources Conservation Service [NRCS]) was used(More)
Bioavailable phosphorus (BAP) in stormwater runoff is a key issue for control of eutrophication in agriculturally impacted watersheds. Laboratory experiments were conducted in soil runoff boxes to determine BAP content in simulated storm runoff in 10 (mostly) calcareous soils from the Minnesota River basin in southern Minnesota. The soluble reactive(More)
Nitrate losses from subsurface tile drained row cropland in the Upper Midwest U.S. contribute to hypoxia in the Gulf of Mexico. Strategies are needed to reduce nitrate losses to the Mississippi River. This paper evaluates the effect of fertilizer rate and timing on nitrate losses in two (East and West) commercial row crop fields located in south-central(More)
As humans and climate change alter the landscape, novel disease risk scenarios emerge. Understanding the complexities of pathogen emergence and subsequent spread as shaped by landscape heterogeneity is crucial to understanding disease emergence, pinpointing high-risk areas, and mitigating emerging disease threats in a dynamic environment. Tick-borne(More)
Increasingly, total maximum daily load (TMDL) limits are being defined for agricultural watersheds. Reductions in non-point source pollution are often needed to meet TMDL limits, and improvements in management of annual crops appear insufficient to achieve the necessary reductions. Increased adoption of perennial crops and other changes in agricultural land(More)
Subsurface tile drains in agricultural systems of the midwestern United States are a major contributor of nitrate-N (NO-N) loadings to hypoxic conditions in the Gulf of Mexico. Hydrologic and water quality models, such as the Soil and Water Assessment Tool, are widely used to simulate tile drainage systems. The Hooghoudt and Kirkham tile drain equations in(More)
Precision farming is possible today because of advances in farming technology, procedures for mapping and interpolating spatial patterns, and geographic information systems for overlaying and interpreting several soil, landscape and crop attributes. The key component of precision farming is the map showing spatial patterns in field characteristics.(More)
The nitrogen sufficiency index (NSI) can be used for in-season variable rate management of nitrogen (N) fertilizer to maintain productivity of potato (Solanum tuberosum, L.) while reducing leaching losses. The objective of this study was to evaluate the implications of using high spatial resolution broad-band imagery for determining N prescriptions at(More)