Performance evaluation of CERES-rice and ORYZA for rice-a case study in the U.S. mississippi delta

Authors: LI, SANAI - US Department Of Agriculture (USDA); Fleisher, David; Timlin, Dennis; Reddy, Vangimalla

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/10/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The United States is the fourth largest rice exporter in the world. However, the warming trends in the Mississippi Delta region are negatively influencing the yield and quality of rice grain. Evaluating performance of crop models is prerequisite to identify the knowledge gaps in the existing models and further improve model's efficiency and accuracy for decision making. First, the response of U.S. rice varieties over 34 years in this region to different climate factors, including rainfall, temperatures, and solar radiation was explored to identify environmental constraints to crop yields and identify adaptation strategies. Second, over 20 years of experimental data from four states in this region were used to examine the accuracy of two of the most popular mathematical models, ORYZA and CERES-Rice, in predicting rice yield and development. The two models were not able to mimic the negative impacts of very warm, or very cold temperatures on rice yield and development, although the models were good predictors of rice yields in the years when there was normal weather. Based on these results, we focused on improving phenological responses of ORYZA. Improving cardinal temperatures resulted in improved model accuracy and reduced systematic error. The default bilinear phenological model was more sensitive to changes in temperature, and thus was more likely to underestimate or overestimate rice developmental responses. A beta-distribution function, which incorporated day and night temperature functions, showed a better performance under warmer and colder climate conditions, especially when temperature was above the optimal value for development. This modified version of ORYZA was used to assess the impact of projected climate change on rice development under future climate. Our studies showed that the warmer temperatures by 2050s are likely to hasten phenological development and shorten growth duration by 2-11 days compared to 1990s. By the 2080s, growth duration was reduced by 8-17 days at a relatively cool site but may increase by 0-4 days at a warmer site. The response of yield to extreme climate events and warmer night temperatures will need to be further developed and improved in ORYZA and CERES-Rice so that these models can be utilized to evaluate climate impacts and adaptation strategies for the U.S. rice production regions.