A unified framework of modeling transpiration responses to water stress in the US Midwest

Plant responses to water stress have been a major uncertainty in predicting terrestrial ecosystem sensitivity to drought. Different theories have been developed to model plant water stress. However, the relationships between these approaches, and their underlying connections to ecohydrologic processes, are not sufficiently understood. In this dissertation, I first proposed a unified theoretical framework in Chapter 2 that reconciles the relationships between different theories and helps identify the water stress characteristics and the most efficient modeling approach for different environmental conditions. Using the framework, I found that empirical approaches of modeling plant water stress are special cases of the full plant hydraulic model. With three case studies across a spectrum of dryness regimes, I evaluated the necessity of incorporating the complexities involved in the hydraulic processes in plant hydraulics models and proposed different modeling strategies for different environments. In Chapter 3, I then applied the above framework specifically to the US Midwest and demonstrated the importance of plant hydraulic transport in crop responses to severe atmospheric dryness. In Chapter 4, I investigated the monitoring of a critical stress factor, soil moisture, at within-field levels using extensive fieldwork and satellite data, thus informing a new integrative approach for high-resolution soil moisture estimation. Finally, in Chapter 5, I used the state-of-the-art satellite evapotranspiration data to constrain and improve land surface modeling at high resolutions. This dissertation contributes to an improved understanding of plant water stress and better monitoring and management of a more sustainable agroecosystem.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Yang, Yi

Contributors dc:contributor

• Guan, Kaiyu
• Dominguez, Francina
• Sivapalan, Murugesu
• Xu, Xiangtao
• Pan, Ming

• Plant Water Stress
• Hydrological Modeling
• Soil Moisture Dynamics
• Model-data Integration

Statement dc:rights

• Copyright 2024 Yi Yang

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/124361

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F124361