Sensitive factors analysis in using GPR for detecting plant roots based on forward modeling

Roots play a crucial role in plant ecosystem.Traditional methods for roots measurements are destructive and labor intensive,limiting the manageability of the size and number of sampling.Ground-penetrating radar(GPR),a nondestructive root analysis method,has already been testified as a feasible and efficient root detection method. However,it is difficult to idetify roots from GPR radargrams. The complexity of root systems and heterogeneity of rhizosphere make the application of GPR to root detection arduous.The feasibility of using GprMax,a GPR profile forward simulation software based on Finite Difference Time Domain(FDTD)theory,for root GPR reflection profiles modeling was validated by comparing simulation results and field experiment results.Furthermore,through developing various forward simulation models,the effect of sensitive factors in using GPR for detecting plant roots was analyzed.Simulation results show that antenna frequency,root system configuration,root water content,root size and depth have obvious impact on root GPR profiles.Conclusions from this paper will help the interpreting of roots GPR reflection profiles and the application of GPR to root detection.