This observation is partially explained by a better calibrated HV model when compared to models which use one or both of the co-polarizations (HH or VV (Fig. 2)). For UAVSAR and corn, strong correlations are reported between estimated and observed LAI with R values of 0.81 (HH–VV), 0.87 (HH–HV), 0.76 (VV–HV) and 0.86 (HH–VV–HV). These results contrast sharply with the results reported for soybeans using L-band with R values of 0.15 (HH–VV), 0.03 (HH–HV), 0.33 (VV–HV), −0.17 (HH–VV–HV). While L-band may be suited to estimate LAI for corn canopies, this frequency is unlikely to provide accurate estimates for lower biomass crops such as soybeans.