Dissertation
UAS-based Remote Sensing Techniques for Detecting Evapotranspiration, and the Effects of LEPA/LESA and MESA Sprinkler Configurations for Precision Irrigation Management
Washington State University
Doctor of Philosophy (PhD), Washington State University
2022
DOI:
https://doi.org/10.7273/000005030
Abstract
This was a study of various methods for site-specific irrigation management. The effects of low elevation spray/precision application system (LESA/LEPA) and mid-elevation spray application (MESA) on spearmint and peppermint oil yield, crop lodging, and evapotranspiration (ET) suppression were studied. The results showed that a LESA/LEPA system could reduce water use by at least 15% without reducing oil concentration and mint oil yield. MESA caused the significantly higher amount of lodging in spearmint. The entropy value, or texture feature, is a viable method for estimating lodging using low-altitude RGB imagery. The total reduction in ET due to the microclimate modifications from wind drift and evaporation losses was small (0.5% of the total applied water) compared to the 15-20% differences in irrigation application efficiency between MESA and LESA. The second part of this thesis focused on improving ET estimation of the unmanned aerial system (UAS)-based METRIC energy balance model. The UAS-METRIC model is adapted from the Landsat METRIC model, which auto-selects two extreme temperatures, a hot pixel (dry, bare soil) and a cold pixel (fully irrigated and fully transpiring crop) for the internal calibration of the model. The results of this study showed that with UAS imagery, auto-selection of hot and cold pixels could result in poor internal calibration due to the limited scale of the imagery. Therefore, temperatures of several reference surfaces were compared with temperatures of dry, bare agricultural soil and fully irrigated grass to find the best correlated artificial hot and cold reference surfaces for the UAS data acquisition. A green sponge floating in the water and a terra cotta saucer plate full of water were the selected artificial cold reference surfaces. These were between 1.9–8.3 °C warmer than the non-stressed spearmint canopy. A dry mulch and dry terra cotta saucer plate were selected as the artificial hot pixel references. Application of dry red mulch/wet sponge and dry/wet saucer plate as artificial hot and cold reference surfaces for internal calibration of the UAS-METRIC model results in overestimating ET compared to using fully irrigated spearmint crop and dry red mulch as the cold and hot pixels respectively.
Metrics
Details
- Title
- UAS-based Remote Sensing Techniques for Detecting Evapotranspiration, and the Effects of LEPA/LESA and MESA Sprinkler Configurations for Precision Irrigation Management
- Creators
- Behnaz Molaei
- Contributors
- R. Troy Peters (Advisor)Claudio Ö. Stockle (Committee Member)Manoj Karkee (Committee Member)Colin S. Campbell (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Biological Systems Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 160
- Identifiers
- 99901019941301842
- Language
- English
- Resource Type
- Dissertation