PS 73-122 - Dryland agrivoltaics: A novel ecosystems approach to the food-water-energy nexus

Friday, August 11, 2017
Exhibit Hall, Oregon Convention Center
J. Jesse Minor1, Rebecca L. Minor1, Isaiah Barnett-Moreno1, Daniel T. Blackett1, Moses Thompson1,2, Chelsea Jones2, M. Blue Baldwin2, Mitchell Pavao-Zuckerman3 and Greg A. Barron-Gafford4, (1)School of Geography & Development, University of Arizona, Tucson, AZ, (2)Tucson Unified School District, Tucson, AZ, (3)Environmental Science and Technology, University of Maryland, College Park, MD, (4)School of Geography & Development; B2 Earthscience / Biosphere 2, University of Arizona, Tucson, AZ
Background/Question/Methods

Conventional understanding of land use asserts an inherent “zero-sum game” of competition between renewable energy and agricultural food production. This discourse is so fundamentally entrenched that it drives most current policy around conservation practices, land and water allotments for agriculture, and permitting for large-scale renewable energy installations. A transformation of the perception of our relationship with nature is required that recognizes the role of humans as both drivers of ecosystem structure and function and as stewards integral to the sustainability of environmental systems. Restoration ecology suggests that ‘novel ecosystems’ – non-historical assemblages of species or types of environmental management– will play an important role in addressing this grand challenge. We are investigating a novel ecosystems approach to solve a problem key to our dryland environment and economy by creating a hybrid of “green” agriculture and “grey” solar photovoltaic (PV) infrastructure to maximize agricultural production while improving renewable energy production. We are monitoring microclimatic conditions, soil moisture, plant ecophysiological function, and biomass production within this novel “agrivoltaics” ecosystem, in conventional devegetated PV installations, and in unshaded agricultural settings (control plot) to quantify tradeoffs associated with this novel ecosystems approach.

Results/Conclusions

Preliminary data show that soil moisture remained higher after each irrigation event under the agrivoltaics installation than in the unshaded traditional agricultural setting. Plants grown throughout the winter and spring maintained higher mid-morning photosynthetic rates in the traditional setting (control), likely because high temperature stress is minimal during this period, and shading under the PV infrastructure limited photosynthetic rates. Still, plants in the unshaded control plot died back due to winter frost events (those under the PV array never experienced frost damage), and showed more signs of stress as temperatures rose in the late spring (indicated by aphid abundance). A drought treatment underscored the water-savings under the agrivoltaics installation and increased water use efficiency in this novel system. Harvested biomass was similar between settings. We have planted new summer crops, and will repeat this same array of measurements and drought treatments to test tradeoffs associated with the agrivoltaics approach. We hypothesize that we will see more temperature and drought stresses on photosynthetic capacity and water use efficiency in the unshaded control plants relative to the agrivoltaic installation. We are piloting parallel installations at two local schools – one elementary and one high school – to stimulate hands-on science and math education within a novel ecosystems setting.