ORE-CZ: The influence of drought, heat waves, and critical zone architecture on water and carbon cycling dynamics of forested dryland agro-ecosystems

Climate change is increasing the frequency and severity of extreme weather events, with heat waves and droughts impacting the crops of large agricultural areas of the country’s arid regions. The resulting shortages of water for irrigation from reservoirs together with drier and warmer weather, forces farmers to change their water sources and increasingly rely on lower quality groundwater to maintain adequate moisture conditions for their crops. Despite these attempts to maintain optimal soil moisture conditions throughout the growing season, scientists have observed decreases in crop productivity due to plant stress from excessive dry and warm atmospheric conditions. At the same time, plant stress is also modulated by the types and structure of the soils on which crops grow. This work will investigate the extent to which changes in soil types and structure can attenuate or exacerbate the stress plants experience when extreme weather occurs and how that is reflected in the growth of the crops, including their ability to sequester atmospheric carbon dioxide, the main greenhouse gas causing climate change. The results from this work will help inform farmers and the public on how to address and mitigate climate change impacts on croplands improving both their water use and their ability to sequester carbon dioxide from the atmosphere. The project will also educate the public regarding these issues by collaborating with a museum in the city of El Paso to create hands-on, interactive research-related learning experiences for children, adults and educators on the theme of climate change in their region. More specifically, this project will focus on studying the response of perennial crops (forested agro-ecosystems) of arid regions to extreme weather by developing a mechanistic understanding of how soil morphology and structure combined with management modulates (1) the effects of environmental stressors (high vapor pressure deficits and low soil moisture) on plant photosynthesis and growth, (2) above and below-ground carbon storage, and (3) the memory of the plants driving morphological and physiological adaptations to cope with adverse atmospheric conditions. The project will implement a continuous tree growth, soil-plant water status, and canopy temperature monitoring system at two proximally located experimental pecan (Carya illinoinensis) orchards located in two of the largest irrigated agro-ecosystem clusters of the Chihuahuan desert. The experimental design will help reveal the mechanisms by which atmospheric aridity and hydrological drought interact with the Critical Zone to impact agro-ecological productivity, soil health, and carbon cycling. Results from this work will provide an opportunity to develop adaptive management strategies to mitigate plant stress in managed ecosystems and help inform how to address and mitigate climate change impacts on forested agro-ecosystems, that are important natural climate solutions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.