Estimation of crop lodging has been extensively investigated. However, mechanisms concerning the variation of crop lodging resistance at different stages of lifecycle during maturation are still unclear. Here, we develop a simplified Euler buckling model to estimate the effect of gradient structural parameters on the lodging resistance and material utilization of rice stem. Three-point bending test was carried out to obtain the stiffness gradient of rice stem. Experimental results show that green rice stem has relatively high material utilization and lodging resistance. When rice stem becomes dry during maturation, the bending rigidity and material utilization of rice stem dramatically decrease, and the weight of panicle increases due to the redistributions of moisture and nutrient substance, which simultaneously increases the lodging risk of rice. The bending rigidity decreases by 71.9; meanwhile, the material utilization of rice stem decreases around 8.7 when rice stem changes from green to dry. Although the stiffness distribution is not the main factor influencing rice lodging, the effect of stiffness distribution of rice stem on its lodging resistance still cannot be neglected during rice maturation.
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