Modeling the Kinematic Response of Rice under Near-Ground Wind Fields Using the Finite Element Method

Plant protection drones are commonly encountered in agricultural fields. Their downwash airflow can agitate flexible crops (e.g., rice and wheat) or even cause wind-induced losses. To predict the wind-induced responses of rice under wind fields, herein, a wind-induced rice response model (RWRM) was proposed using the finite element method. With the RWRM, the rice displacement and critical wind speed (CWS) were calculated at different wind speeds, considering the morphological and mechanical properties of rice, and the accuracy was experimentally verified and compared to that of an existing model. The results indicated that the mean paired difference and mean error in rice displacement amplitude prediction under 2~5 m/s wind speeds were 13.48 mm and 42.46 mm, respectively, and the predicted and measured values were highly correlated at the 1% significance level. Moreover, the CWS values for four rice species could be calculated with the model with an average of 3.57 m/s, and the difference between the simulated and theoretical values was 0.368. The strength of the wind-induced rice responses was primarily correlated with the mechanical properties, and to a lesser extent the morphology. The rice yield has a negative correlation with rice responses. Within a certain range, a bigger displacement and lower CWS could result in a higher rice yield. The RWRM achieved favorable modeling accuracy for the wind-induced responses of rice and could provide a simulation reference for balancing the wind-induced loss and rice yield.