Vulnerabilities of irrigated and rainfed corn to climate change in a humid climate

Authors: Anapalli, Saseendran; Fisher, Daniel; PINNAMANENI, SRINIVASA - Oak Ridge Institute For Science And Education (ORISE); Reddy, Krishna

Submitted to: Climatic Change
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2021
Publication Date: 1/18/2021
Citation: Anapalli, S.S., Fisher, D.K., Pinnamaneni, S.R., Reddy, K.N. 2021. Vulnerabilities of irrigated and rainfed corn to climate change in a humid climate. Climatic Change. 164(5):1-18. https://doi.org/10.1007/s10584-021-02999-0.
DOI: https://doi.org/10.1007/s10584-021-02999-0

Interpretive Summary: Recent trends observed in increasing greenhouse gases in the atmosphere are affecting the climate over the earth adversely. As the climate, especially temperature and rainfall, impact agricultural production significantly, it is necessary to evaluate and develop mitigation and adaptation strategies for assuring sustained crop-productivity as the climate changes. Researchers with the USDA ARS Sustainable Water Management Research Unit at Stoneville, MS, investigated future rainfed and irrigated corn production under climate change predicted by global climate models, and explored adaptation strategies to avoid adverse impacts on production. Over a range of greenhouse gas emission scenarios possible by as early as 2050, air temperatures and CO2 were predicted to rise considerably. In response, corn yields can decrease significantly both under rainfed and irrigated corn management. As an adaptation measure, planting corn earlier in the season, in general, failed to boost yields from a reduction in air temperatures as incidences of low temperatures that can kill corn also increased alarmingly. Development of cultivars that are more heat tolerant and produce higher yields under extreme temperatures would be required to check corn yield loss in the region from the current global warming.

Technical Abstract: Use of fossil fuels for energy needs continues to enhance atmospheric greenhouse gas (GHG) concentrations to levels that can exacerbate the climate on earth significantly. Assessing the vulnerability of regional crop production systems to such an altered climate in the future is essential for implimenting appropriate adaptation and mitigation strategies for sustainable agriculture. We investigated the possible impacts of climate change (CC) projected by multiple global climate models (GCMs) on rainfed and irrigated corn (Zea Mays L.) in the Lower Mississippi Delta region (LMD), USA. The CSM-CROPGRO-Maize v4.6 module in the RZWQM2 model (hereafter referred to as the ‘corn model’) that was previously calibrated and tested for simulating corn at Stoneville, Mississippi, a representative location in the LMD, was used. The CC scenarios considered in this study were ensembles of climate projections of multiple GCMs (97 ensemble members) that participated in the Climate Model Inter-comparison and Improvement Program 5. These CC scenarios were bias-corrected and spatially downscaled (BCSD) at the location for the years 2050 and 2080. Four representative GHG concentration pathways (RCP) 2.6, 4.5, 6.0, and 8.5, drove these CC scenarios. Under both irrigated and rainfed conditions, corn yield responses to enhanced CO2 were negligible; as such, yield declined significantly in response to the enhanced air temperatures under the CC scenarios in both 2050 and 2080. The yield declines across RCPs ranged between 10 and 62% under irrigated conditions, and between 9 and 60 % under rainfed conditions, mainly due to increased frequency of extreme temperatures and reduced crop durations. Water use efficiency declined between 22 and 150 % under irrigated, and 8 and 54% under rainfed management. As an adaptation measure, planting corn up to 9 weeks earlier in the season, in general, failed to boost yields from increased crop duration and reduction in upper extreme air temperatures, as incidences of lower extreme temperatures also increased alarmingly. Development of cultivars that are more heat tolerant and produce higher yields under extreme temperatures would be required to combat corn yield decline in the region from climate change.