Laser depolarization ratio measurement of corn leaves from the biochar and non-biochar applied plots

Research has shown that biochar, when used as a soil amendment, can improve soil quality and potentially increase agriculture production. This case study was targeted at comparing the polarimetric laser reflectivities of the corn (Zea mays L.) leaf samples collected from two plots: the biochar plot with corn stover biochar previously applied, and the control plot without any biochar treatment. Specifically, measurements of the co-polarization and the cross-polarization components of the corn leaves at 532-nm laser wavelength were performed. It was discovered that the leaf samples collected from the control plot had larger depolarization ratio in comparison to these from the biochar plot. Data analysis showed that the depolarization difference was statistically significant. Such difference is attributed to the application of biochar. This study agrees with the conclusion that biochar improves soil fertility from previous literature using direct measures. In addition, it suggests that laser depolarization ratio can be used as an indicator to monitor plant growth condition. Furthermore, our finding improves the understanding and application of leaf laser polarimetry, provides future research directions toward the leaf and plant polarimetric scattering models, and will contribute to the design of future remote sensing polarimetric lidar in agriculture and forest remote sensing.