Investigating the Health of a Rice Field Ecosystem Using Thermodynamic Extremal Principles

This study investigates the dynamic behaviour of a rice field ecosystem and aims to define its integral features using the stability concept of an ecological goal function. This function is based on the extremal principles of thermodynamics, which assume that certain energetic processes of ecosystems—such as the rate of exergy destruction—are directed by the self-organizing informatics of the systems towards maxima or minima. In our study, we exploit the availability of substantially long time-series data relating to a rice field ecosystem to gain an evocative understanding of its growth trajectory in light of the thermodynamic principles. We accomplished this by constructing a model based on the STELLA 9.0 software and calculating the extremal values of growth rates (storage) and those of exergy destruction and entropy creation. The results showed that the values of both maximum dissipation and maximum exergy progressed apace with that of maximum storage till the maturation of rice and became stable thereafter, whereas maximum residence time and maximum specific dissipation values initially decreased before their asymptotic rise. A similar pattern was also observed for the maximum specific exergy. However, the maximum power dissipation curve followed a highly fluctuated course before becoming stable on the maturation of rice.

本研究聚焦稻田生态系统的动态行为，旨在借助生态目标函数的稳定性概念阐明其整体固有特征。该函数基于热力学极值原理，该原理假定生态系统的部分能量过程——例如（火用）（exergy）耗散速率——由系统的自组织信息机制调控，趋向于最大值或最小值。本研究依托长期连续的稻田生态系统时序数据，基于热力学原理对其生长轨迹形成具象化的深入认知；为此，我们基于STELLA 9.0软件构建模型，计算了生长速率（存储量）、（火用）耗散及熵产的极值。研究结果显示，最大耗散量与最大（火用）值的变化趋势与最大存储量始终保持同步，直至水稻成熟，此后趋于稳定；而最大驻留时间与最大比耗散率则先呈下降趋势，随后渐近式上升。最大比（火用）值也呈现出类似的变化规律，但最大功率耗散曲线则呈现出大幅波动的走势，直至水稻成熟后才趋于平稳。