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Graduation Term


Document Type

Thesis-ISU Access Only

Degree Name

Master of Science (MS)

Committee Chair

Wondwosen M. Seyoum


With the growing problems of water quality in different parts of the US that use tile drainage systems for agricultural developments in sustainable productivity, locating and developing efficient and cost-effective method of mapping tile drainage is mandatory. Subsurface drainage system has been practiced for more than 100 years in the US, especially, in the Midwest region. However, the locations of some tile drainage systems have been ambiguous due to change in ownership and lack of historical documentation. This research aims to develop a method of mapping subsurface drainage systems in agricultural fields using optical and radiometric thermal sensors mounted on Unmanned Arial Systems (UAS) based on the assumption that volumetric water content of soils in an agricultural field has a different signature of temperature along the tile lines and in between the tiles after a rainfall event. Therefore, three types of sensors including FLIR Vue pro R Thermal sensor (to map thermal signature), DJI FC 6510 ZENMUSE X4S RGB, and DJI FC330 phantom 4 Quadcopter camera (to create a digital surface model) mounted on two types of drones: DJI M200 V2 and DJI phantom 4 were used. Total of 7 flights conducted a couple of weeks after plantation of soybean and after harvesting of the soybean plant. The flight was designed to compare the effectiveness of the UAS under different conditions such as before rainfall versus after rainfall, crop cover versus non-crop cover, age of crop cover, time of the day with a maximum change in temperature, and intensity of rainfall. Image processing was accomplished using Agisoft, PIX4D, and ENVI image analysis software. All the image analysis, statistics, and processing of digital surface model and thermal map showed that UAS is most efficient under the conditions of relatively mature crop cover (25-30cm), rainfall greater than 0.09 inches, relatively warmer season, and flights conducted from 2:00 PM to 6:00 PM in the afternoon and 5:00 AM to 7:00 AM in the morning where maximum change in temperature exists between the tile line and the adjacent zones.


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