Browsing by Author "Baker, John"

Now showing 1 - 5 of 5
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    Mn/ROAD TDR Evaluation and Data Analysis
    (Minnesota Department of Transportation, 2003-12-01) Wang, Dong; Baker, John
    Water content measurement using time domain reflectometry (TDR) is an important integral component of the Minnesota Road Research Project (Mn/ROAD) program. However, erroneous and inaccurate water content values are frequently generated using current data collection and interpretation procedures. Whereas the erroneous and obviously unreasonable values are caused by limitations of the current waveguide/cable systems, inaccurate water content values are most likely caused by the inadequacy of the empirical calibration equations. Base, Subbase, and Subgrade materials are different from agricultural soils in composition, water retention characteristics, and more importantly in their dielectric properties in relation to water content and temperature regimes in the road pavement. This project was to develop a new composition-based calibration between water content and apparent dielectric constant of the pavement materials. Temperature effect on the dielectric constants of water and pavement components was also integrated in the new calibration. Results indicated that the new calibration was more theoretically sound and relatively simple to use. Additional tests and developments may be needed to further validate the reliability of the new approach.
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    Proceedings of the 3rd Soil and Water Management Field Day and Workshop
    (2008-08-13) Strock, Jeffrey S.; Baker, John; Pitts, Don; Birr, Adam; Rice, Pam; Venterea, Rod
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    Proceedings of the 5th Soil and Water Management Field Day
    (2014-07-23) Strock, Jeffrey S.; Baker, John; Hatfield, Jerry; Sereg, Catherine; Todey, Dennis; Wohnoutka, Shawn; Castellano, Mike; Ingels, Chad; Tollefson, David
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    Testing of Soil Heat and Water Flow Models
    (1993-01) Newcomb, Dave; Baker, John; Xu, Xia; Neiber, John
    The SHAW model ( Simultaneous Heat And Water ) is tested with water content and temperature profile data for a soil located near Rosemount Minnesota. The predicted frost/thaw depth, soil water content, and temperature at depths of 10, 20, 40, 80, and 100 cm are compared to measured values. The results show that the prediction of frost depth and temperature profile agree well with measured field data, while agreement between measured and predicted liquid water content is not as good.
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    Winter Rye Best Management Practices to Reduce Loads of Sediment and Nutrients to Minnesota Surface Waters
    (2011) Herges, Adam; Krueger, Erik; Baker, John; Porter, Paul; Feyereisen, Gary; Allan, Deborah; Ochsner, Tyson; Nater, Edward A.
    Surface runoff from agricultural fields is potentially harmful to our environment because of excessive loads of sediment and nutrients. Industrialized agriculture has provided food for the world, but has also created unintended water quality problems. Excessive nutrient contamination in the Gulf of Mexico has created a zone of hypoxia where dissolved oxygen levels are too low to support aquatic life. The Upper Midwest agriculture is mostly comprised of corn and soybeans and a large amount of the nitrogen (52%) reaching the Gulf of Mexico is a result of this cropping rotation (Alexander, 2008). In addition, up to 50% of applied synthetic fertilizer on Midwestern soils is lost every year due to rainfall and surface runoff (Tonitto, 2006). However, adding cover crops to an agricultural rotation provides soil cover and retention of nutrients. Various studies have shown that a winter rye cover crop can reduce nitrate leaching by 70% (Tonitto, 2006; Ball Coelho, 2005; Staver and Brinsfield, 1998). However, the use of cover crops in the United States Corn Belt is not widely accepted nor implemented. A survey where 3,500 farmers were asked to provide information on cover crop use showed that only 11% of farmers in the Upper Midwest have used cover crops in the last five years (Singer, 2007). This study will develop Best Management Practices (BMPs) for beef and dairy producers that will make cover crops economically viable. Winter rye offers great potential for environmental benefits on land where corn silage or stover is removed to feed livestock. If the winter rye is established early enough, it can be grazed or harvested as forage in the spring before a cash crop is planted. Two locations in southern Minnesota have been selected for monitoring surface runoff and developing viable cover cropping BMPs. Each location consists of a paired watershed design where one watershed is the control (conventional practice) and the other is the treatment (winter rye following corn harvest). The first location will have winter rye aerially seeded into standing corn grain with spring grazing of the winter rye. The second location will have drilling of winter rye following corn silage harvest with winter rye harvested as forage in the spring prior to soybean planting. This study will encompass two full growing seasons from 2009 to 2011. Additional small plot experiments with the use of a rainfall simulator to evaluate surface runoff differences between conventional practices and cover crop BMPs.