Estimation of pasture biomass using dual-polarisation radar imagery; a preliminary study

The efficient management of pasture is a key driver of profitability for New Zealands pastoral dairy and meat industries. Regular monitoring of available pasture feed and feed quality are required regularly for dairy operations. In this paper, we report preliminary results from a study that tests the viability of using short-wavelength imaging radar to estimate pasture biomass. We use six (out of 36) images from the TerraSAR-X satellite, comparing the HH & HV and VV&HV dual-polarisation combinations. Several linear models have been tested for field-measured pasture biomass. The best model is a linear regression using backscatter from the HH & HV combination, resulting in a residual standard error of 191.4 (kg/ha). Most important, this polarisation combination showed no evidence of a date effect, which suggests that this polarisation combination can provide estimation of pasture biomass independent of the surface environmental conditions.