Investigating plant root signatures using geo-electrical methods
(2020)
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- Abstract
- Thorough knowledge of root system architecture and functioning is essential for a better understanding of the impact of plants on climate change, for plant phenotyping or for designing more sustainable agro-ecosystems. Recently, electrical imaging of root zone soil has been gaining wide attention among agronomists and soil scientists. The general objective of this Ph.D. thesis is to quantify the direct and indirect impact of plant roots in soil electrical signature. Root affects the soil-plant system directly through its architecture but also indirectly via soil water depletion by uptake. The first part of the thesis (Chapters 3 and 4) deals with understanding the direct impact of roots in small scale rhizotron and pot via process-based numerical models. We quantify the direct impact of roots while incorporating both direct (root explicit electrical properties) and indirect (root water uptake patterns) in the forward numerical model. To date this is the closest to reality, a numerical model can achieve in understanding electrical signatures of root systems in soils. We also prove that electrical response if measured in magnitude and phase components, magnitude part represents mainly indirect impact (root water uptake) while the phase part represents mainly direct impact (root architecture) and both magnitude and phase part contain root geometrical information. The second part of the thesis deals with quantifying the indirect impact of water, i.e., soil water depletion in field-scale ERT experiments. We propose a new methodology where we use a numerical model to interpret field data. The model informed us if the changes we observe in the ERT experiment was due to plants or an artifact. This allowed us to quantify even the slightest changes in water depletion from different plants. Finally, application of the ERT method to phenotype root systems is demonstrated on grasslands. Sathyanarayan Narasimhan Rao holds Bachelor of Engineering in Electronics and Communication (2010) from Visvesvaraya Technological University in India, Master of Science in Electrical Engineering (2012) from the University of Alabama in Huntsville in USA, Master of Science in Physics (2014) from the Alabama A&M University in USA. Before coming to UCLouvain, he worked as a research assistant in Computational Optoelectronics at the University of Paderborn in Germany. At UCLouvain, he pursued doctoral research for four years from May, 2016 to Aug, 2020 as a FNRS fellow.
- Affiliations
UCLouvain SST/ELI/ELIE - Environmental Sciences UCLouvain Faculty of Architecture, Architectural Engineering, Town Planning (LOCI)
Citations
Rao, S. N. (2020). Investigating plant root signatures using geo-electrical methods. https://hdl.handle.net/2078.5/114954