Mapping of hailstorm and strong wind damaged crop areas using LAI estimated from multispectral imagery

Hailstorms and strong winds represent a threat to crops, causing defoliation, lodging and in turn yield losses. Crop damages are nowadays assessed by field inspectors, which implies time demanding assessment and difficulties in deriving estimates over large areas. Hailstones and strong wind damage plants through stem breaking, defoliation and lodging, thus leaf area index (LAI) can be a viable tool to detect and quantify the damage level. Here, hailstorm and strong wind damage was artificially caused in a maize field and compared with NDVI-derived LAI from proximal and remote sensing techniques. Estimated LAI was obtained by a NDVI-derived fractional vegetation cover and calibrated light extinction coefficient. Results showed that estimated LAI from remote sensing was able to identify crop damage, with a clear differentiation between leaf damage levels immediately after the event. Following surveys showed a strong recovering capability of maize leading LAI values of damaged treatments to align to those of the control after about 20 days. Remote sensing techniques, coupled with ground measurements, can become a reference tool to assess site-specific hailstorm and strong wind damage over large areas.