作物生长‒土壤水分利用效率耦合模型构建及关键驱动因子解析

Construction of Crop Growth-soil Water Use Efficiency Coupling Model and Analysis of Key Driving Factors

摘要:

基于高性能地下水动力模型SERGHEI-RE和作物生长模型WOFOST，构建了作物生长?土壤水运动动态耦合模型，并利用田间观测数据完成模型率定与验证。借助该模型，通过构建土壤水力性质数据集和未来气候变化情景，探究土壤水力性质和气温变化对水分利用效率（WUE）的影响机制。模拟结果表明，气温升高加快了作物发育进程，但总体上气温每升高1 °C，作物产量减少0.88%~2.92%，水分利用效率减少7.75%~7.96%。沙壤土可调节蒸腾作用，缓解因气温上升而导致的水分利用效率下降，展现出更强的高温适应潜力。时间滞后交叉相关性分析表明，叶面积指数（LAI）与土壤水分（SM）存在非对称滞后效应，叶面积指数变化驱动土壤水分下降的响应较快（滞后约10~25 d），而土壤水分变化调控叶面积指数生长的响应较慢（滞后约40~60 d），且该效应因土壤类型与气温升高而异。随机森林模型结合SHAP分析进一步揭示了气温与土壤孔隙直径分布是水分利用效率的关键影响因子。

Abstract:

In this study， a dynamic coupling model integrating crop growth and soil water movement is developed， by combining the high-performance groundwater flow model SERGHEI-RE with the crop growth model WOFOST. Field observation data are utilized for model calibration and validation. Through this modeling framework， the effects of soil hydraulic properties and air temperature on water use efficiency （WUE） are investigated by constructing representative soil hydraulic datasets and future climate change scenarios. Simulation results demonstrate that elevated temperatures accelerate crop phenological development but concurrently reduce crop yield by 0.88%?2.92% and WUE by 7.75%?7.96% per 1 °C increase. Sandy loam soil can mitigate the WUE decline under warming conditions through regulating transpiration dynamics， showing the greater thermal adaptation potential. Time-lagged cross-correlation analysis reveals an asymmetric hysteresis relationship between the leaf area index （LAI） and soil moisture （SM）. The LAI-driven SM depletion responds rapidly （10?25 d lag）， whereas the SM-regulated LAI growth exhibits delayed responses （40?60 d lag）. This hysteresis is further modulated by soil types and temperature elevation. The air temperature and soil pore-size distribution are identified by random forest modeling and SHAP as dominant factors governing WUE.