|BROUGHTON, KATRINA - Csiro, Australian Cotton Research Institute, Narrabri|
|TAN, DANIEL - University Of Sydney|
|TISSUE, DAVID - Western Sydney University|
|BANGE, MICHAEL - Csiro, Australian Cotton Research Institute, Narrabri|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2020
Publication Date: 8/26/2020
Citation: Broughton, K., Payton, P.R., Baker, J.T., Yates, C.E., Tan, D., Tissue, D., Bange, M. 2020. Effects of elevated CO2 and warmer temperature on early-season field-grown cotton in high-input systems. Crop Science. https://doi.org/10.1002/csc2.20313.
Interpretive Summary: Changes in climate factors such warmer air temperatures and extreme fluctuations in precipitation as a result of rising CO2 concentration may significantly impact plant growth and crop productivity. Over the past several years a range of research initiatives have been conducted to better understand responses of the cotton system to this changing environment. This paper explores the utility of Canopy Evapo-Transpiration and Assimilation (CETA) chambers to evaluate the impact of climate change on field-grown plants. The CETA chambers were designed at the USDA-ARS Cropping Systems Laboratory as a low-cost, portable system to monitor plant response to a range of environmental conditions, including elevated CO2 and temperature. CETA chambers were a successful method of increasing atmospheric [CO2] of field-grown cotton, despite limitations of increased temperature and altered humidity during late afternoon periods. Elevated CO2 increased early stage biomass of well-watered, field-grown cotton, suggesting that early-season cotton growth may be increased in warmer, higher CO2 environments and thus, could increase water requirements in elevated CO2 climates. While we did not obtain a definitive answer to the integrated effects of elevated CO2 on plant water use, preliminary data suggests that this increased growth is not consistent in water- or temperature-limiting conditions and thus, the benefit of increased atmospheric CO2 on growth may not be realized in stressful environments. Therefore, due to these conflicting findings particularly around water use, this study indicates that further studies should be conducted to explore the integrated environmental effects of climate change on in field-grown cotton in irrigated and rainfed production systems.
Technical Abstract: Changes in temperature, CO2, and precipitation under the scenarios of climate change present a challenge to crop production, and may have significant impacts on the yield of cotton crops (Gossypium hirsutum L.). Understanding the implications of varied environmental conditions for agricultural crops is critical for developing cropping systems resilient to stresses induced by climate change. The aim of this study was to investigate the use of novel chambers that could be used to evaluate the impacts of climate change on field-grown plants. Canopy EvapoTranspiration and Assimilation (CETA) chambers were used to elevate atmospheric [CO2] in the field over two consecutive cotton seasons. Cotton plants were grown under CETA chambers at higher temperatures (on average 2oC - 4 oC warmer) either at ambient [CO2] (CA: 400 ppm) or elevated [CO2] (CE: 650 ppm) from approximately 44 days after planting (DAP) until 72 DAP (28 days total for each season). The CETA chambers were a successful method of increasing atmospheric [CO2] of field-grown cotton. Elevated [CO2] increased early stage vegetative biomass by 34 - 68% in well-watered, field-grown cotton growing at warmer temperatures. Despite some changes in leaf-level physiology, there were no large changes in either leaf-level biochemistry or changes in volumetric soil water content. Thus, we did not obtain a definitive answer to the integrated effects of CE and warmer temperatures on plant water use. Data from this study contributes to the body of information on the possible impact of climate change on early-season crop growth; however, further studies are needed to assess the effects that altered environmental conditions have on cotton production over a full growing season.