Modeling climate warming impacts on grain and forage sorghum yields in Argentina

Authors: DRUILLE, MAGDALENA - Universidad De Buenos Aires; Williams, Amber; TORRECILLAS, MARCELO - National University Of Lomas De Zamora; KIM, SUMIN - Oak Ridge Institute For Science And Education (ORISE); MEKI, NORMAN - Texas Agrilife Research; Kiniry, James

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2020
Publication Date: 7/4/2020
Citation: Druille, M., Williams, A.S., Torrecillas, M., Kim, S., Meki, N., Kiniry, J.R. 2020. Modeling climate warming impacts on grain and forage sorghum yields in Argentina. Agronomy. 10(7). Article 964. https://doi.org/10.3390/agronomy10070964.
DOI: https://doi.org/10.3390/agronomy10070964

Interpretive Summary: As a crop, sorghum is the fifth most common in the world. Its growth could be affected by increased future air temperature, an important component of global climate change. Our objective was to use a process based computer simulation model (ALMANAC) to a) evaluate the impact of climate warming on forage and grain sorghum production in Argentina, and b) to analyze to what extent yield changes were associated with changes in water or nitrogen stress days. To calibrate the model, we used previous information related to the plant characteristics of both sorghum types and several soil parameters. We then used several years of field data of sorghum yields for model validation. Yield simulations were conducted under three possible climate change scenarios: 1, 2 and 4 °C increase in mean annual temperature. ALMANAC successfully simulated yields of forage and grain sorghum. Forage yield increased and grain yield decreased as mean annual temperature increased. Yields of forage sorghum were negatively associated with nitrogen stress, while grain sorghum yield was negatively associated with water stress. The information generated allows anticipating future changes in crop management and genetic improvement programs in order to reduce the yield vulnerability.

Technical Abstract: Sorghum is the world’s fifth major cereal in terms of production and acreage. It is expected that its growth will be affected by the increase in air temperature, an important component of global climate change. Our objective was to use the Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) model to a) evaluate the impact of climate warming on forage and grain sorghum production in Argentina, and b) to analyze to what extent yield changes were associated with changes in water or nitrogen stress days. For model calibration, we used previous information related to the morpho-physiological characteristics of both sorghum types and several soil parameters. We then used multi-year field data of sorghum yields for model validation. Yield simulations were conducted under three possible climate change scenarios: 1, 2 and 4 °C increase in mean annual temperature. ALMANAC successfully simulated mean yields of forage and grain sorghum: root mean square error (RMSE): 2.6 and 1.0 Mg ha-1, respectively. Forage yield increased 0.53 Mg.ha-1 and grain yield decreased 0.27 Mg.ha-1 for each degree of increase in mean annual temperature. Yields of forage sorghum tended to be negatively associated with nitrogen stress (r = -0.94), while grain sorghum yield was negatively associated with water stress (r = -0.99). The information generated allows anticipating future changes in crop management and genetic improvement programs in order to reduce the yield vulnerability.