A Dynamic Model for the Relationship between Rice Growth and Meteorology, Water, Nitrogen, and Canopy Structure

Abstract

HighlightsA simulation model was built for understanding rice growth dynamics.Two rice cultivars under two nitrogen fertilization conditions were simulated.Simulated dry weight agreed well with the measured values.Daily maximum temperature was negatively correlated with rice growth.Abstract. Crop growth models are highly effective tools for solving various practical problems in agriculture, such as farm decision-making, agronomic management, and prediction of climate change impact on crop growth. This article presents a robust model to explain the dynamics among microclimate, canopy structure, and rice biomass growth based on ecological, physiological, and physical processes. Meteorological values, leaf area index (LAI), plant height, and dry weight of leaf, stem, and panicle were intermittently measured in the field for two rice cultivars under two different nitrogen (N) fertilization conditions during the 2017 and 2018 growing periods. Based on these measurements, a comprehensive and robust growth model, the Integrated Rice Growth Model (iRGM), was developed for rice growth simulations under various meteorological, fertilizer, and water conditions. The results showed that the iRGM provided sufficient quantitative explanations for the measured rice growth dynamics in the field compared with the ORYZA2000 model. Moreover, parameter sensitivity analyses showed that the initial slope of the light response curve had a significant effect on the dry weight throughout the growing period. Growth conversion efficiency, maintenance respiration rate, and daily increase in LAI also had larger influences on rice growth. On the other hand, the maximum temperature, which increased by 10% over the values obtained in the rice field, was negatively correlated with growth. This model would be useful for quantitative evaluations and predictions of complex systems encountered in environmental management and cultivar stability. Keywords: Canopy structure, Dry weight, Microclimate, Rice dynamic growth model, Sensitivity analysis.