Impacts of air pollution on productivity of natural and cultivated tropical C4 grasses: implications in the face of land use change in Brazil

Lead Research Organisation: UNIVERSITY OF EXETER
Department Name: Geography

Abstract

In the lower atmosphere ozone (O3) is an important anthropogenic greenhouse gas and is an air pollutant responsible for several billion pounds in lost plant productivity each year. Surface O3 has doubled since 1850 due to chemical emissions from vehicles, industrial processes, and the burning of forests. Tropical ecosystems are responsible for nearly half of global plant productivity and it is in these tropical regions that we are likely to see the greatest expansion of human populations this century. Alongside this growing population, we see the expansion of O3 precursor emissions from urbanization and high-intensity agricultural areas.

Sugarcane is an important tropical and bioenergy crop, supplying raw material for sugar, ethanol (biofuel) and energy production and contributes to the bioeconomy of both São Paulo state (SP) and Brazil. While the São Paulo state is responsible for over half of Brazilian sugarcane production, sugarcane-derived products account for 17% of the Brazilian energy matrix. In a global context, biofuel production is one major land-based carbon-neutral approach to reduce our reliance on fossil fuels, and thus help society to achieve the challenging Paris accord of limiting climate change to below 2oC.

Over the two last decades, SP state has experienced large-scale conversion of pasture (natural C4 grass) to sugarcane fields. At the same time air quality measurements demonstrate O3 concentrations across much of SP above those known to be harmful to plants.

This project will make the first comprehensive set of measurements of O3 effects on plant functioning and growth in tropical grasses, both cultivated (e.g. sugarcane) and natural (e.g. used as pasture) using our unique tropical experimental facility in Cairns, Australia. Here we expose tropical grasses to different levels of ozone, to derive relationships between O3 dose and productivity loss. In addition, we investigate the role of drought on the O3 sensitivity of tropical grasses.

Finally, we will use this information to assess the impact of regional O3 concentrations and changing land-cover (from natural C4 pasture to sugarcane) for southern Brazil and engage with relevant stakeholders from both policy and academia.

Publications

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Brown F (2022) The ozone-climate penalty over South America and Africa by 2100 in Atmospheric Chemistry and Physics

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Cheesman AW (2023) Impacts of ground-level ozone on sugarcane production. in The Science of the total environment

 
Description we found sugarcane to be sensitive to air pollution, but sensitivity was variety specific. We also simulated large reductions in productivity of sugarcane due to ozone over São Paulo state Brazil (50% of Brazil's sugarcane is produced in SP state).
Exploitation Route Our collaborator applied for FAPESP funding to continue this work (albeit they would only be funded, so my contribution would be in-kind).
Sectors Agriculture

Food and Drink

Environment

 
Title Maps showing risk and potential impacts of ozone on sugarcane production in south-central Brazil, 2010-2014 
Description This dataset contains gridded model outputs of the predicted risk to C4 sugarcane production across south central Brazil for 2010-2014. The outputs are given as production in kg m-2 yr-1, percentage of control production (%) and production losses in kg yr-1 and Tg yr-1. The spatial resolution is 1.25 x 1.875 degrees. Three different levels of ozone susceptibility (low, moderate or high) and two distinct threshold values of phytotoxic ozone dose (0 and 2 nmol m-2 s-1) were considered. 
Type Of Material Database/Collection of data 
Year Produced 2024 
Provided To Others? Yes  
URL https://catalogue.ceh.ac.uk/id/1513d8ed-67a9-40fc-a8e5-bd7864d0d422
 
Title Plant biomass and leaf-level functional traits from four different genotypes of sugarcane plants grown under a range of ozone conditions 
Description This dataset contains measurements of plant biomass and leaf-level functional traits from sugarcane plants of four different genotypes that were grown under different ozone (O3) conditions in Open Top Chambers for approximately 90 days. It also contains the calculated phytotoxic ozone dose for each of the four genotypes, the O3 concentration measurements and the environmental conditions (air temperature, relative humidity, and photosynthetically active radiation). The four genotypes tested were: Saccharum officinarum L. cv. Badila, Saccharum spontaneum cv. Mandalay, Q240, and CTC4. 
Type Of Material Database/Collection of data 
Year Produced 2024 
Provided To Others? Yes  
URL https://catalogue.ceh.ac.uk/id/68adb7d4-6138-4d70-b469-2471349b331a