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Analysis Of The Influence Of Soil Temperature And Soil Surface Conditions On Soil Moisture Estimation Using The Theta Probe , Geetika Dilawari Jan 2006

Analysis Of The Influence Of Soil Temperature And Soil Surface Conditions On Soil Moisture Estimation Using The Theta Probe , Geetika Dilawari

Retrospective Theses and Dissertations

Soil moisture is an important component of numerous systems, influencing crop development, and runoff and infiltration partitioning, among other things. However, due to its spatial and temporal variability, it is difficult to estimate soil moisture consistently using conventional techniques such as gravimetric sampling, which is point-based and time-consuming. Therefore, to overcome this drawback in soil moisture estimation and mapping, and to facilitate its measurement spatially and temporarily, remote sensing in microwave, visible, near infrared and short wave infrared is being explored and is proving to be a promising technique. But to develop models using spectral data there is a need ...


Permeation Studies Of Pvc Pipes With Near Infrared Spectroscopy , Lidia Esteve Agelet Jan 2006

Permeation Studies Of Pvc Pipes With Near Infrared Spectroscopy , Lidia Esteve Agelet

Retrospective Theses and Dissertations

Polyvinyl chloride (PVC) is commonly used for drinking water pipes. Although PVC is resistant to natural environmental conditions, organic solvents may attack the pipe wall causing swelling, softening, water lines failure and drinking water pollution. Permeation is linked to underground storage tanks and random accidental spills of organic solvents or fuel derivates. Although rare, several cases have been reported. This thesis was developed with the idea of increasing the understanding of permeation process, developing new laboratory methods for permeation testing, and helping pipe companies in assess about pipe selection in zones of high risk. Near infrared spectroscopy (NIRs) was selected ...


Integration Of Remote Sensing And Crop Growth Modeling For Nitrogen Management Decision Support In Corn , Kelly Robert Thorp Jan 2006

Integration Of Remote Sensing And Crop Growth Modeling For Nitrogen Management Decision Support In Corn , Kelly Robert Thorp

Retrospective Theses and Dissertations

This dissertation describes efforts to move toward a completely integrated remote sensing and crop growth modeling tool for developing precision nitrogen management recommendations for corn. Aerial hyperspectral remote sensing imagery collected throughout the 2004 growing season was used to estimate corn plant stand density, and a machine vision system was used to map corn population on the ground. Multiple linear regression analysis was used to assess the ability of all combinations of three reflectance bands to estimate corn plant population at resolutions of 2 m, 6 m, and 10 m. Coefficients of multiple determination of up to 0.82 were ...


Vegetative Filter Strip Assessment In The State Of Iowa, Manveen Bansal Jan 2006

Vegetative Filter Strip Assessment In The State Of Iowa, Manveen Bansal

Retrospective Theses and Dissertations

Vegetative filter strips (VFS) is one of the best management practices that uses natural processes to remove a portion of the sediment and other pollutants carried by runoff before the water enters a water-body. The project analyzes the flow accumulation of runoff with the help of Geographic Information Systems (GIS). The objectives for this project include (1) To determine the effectiveness of VFS by visual field observation and validation by flow mapping procedures in ArcGIS 9, (2) To compare the area ratios and percentage of flow along each stream segment at various resolutions for different sizes of the survey data ...


Hydrological Modification Of Subsurface Drainage Systems , Kyle Dean Riley Jan 2006

Hydrological Modification Of Subsurface Drainage Systems , Kyle Dean Riley

Retrospective Theses and Dissertations

Controlled Drainage (CD), a subsurface drainage management system, has been researched in many regions. Previous research has reported CD to reduce subsurface drainage and as a result reduce nitrate loading. CD has been reported to have little effect on nitrate concentrations, so exploring alternative treatments to reduce these concentrations would be constructive. This research was intended to measure the effect of CD on surface runoff, crop yield, water table depth, and to document a biofilter's effect on nitrate concentrations. CD increased surface runoff ranging from 53% to 130%, increased corn yield by 14% over two years, and decreased nitrate ...