Amazing Grazing; Grass growth measurements with remote sensing techniques

Quantifying grass production is considered essential for adequate grassland management on grass based dairy farms. Spectral imaging with remote sensing techniques could be an alternative for labour intensive grass height measurements. In a cutting experiment with a factorial combination of nitrogen fertilisation and grass growth intervals, grass growth was measured with a Cropscan Multispectral Radiometer measuring light reflectance in eight or 16 bands (ground truth measurement). The aim of the experiment was to see whether vegetation indices can be used to quantify actual grass biomass. Preliminary results of the first year of the project showed that some vegetation indices were well related to grass yield. However, this relationship was best for individual cuts, meaning that correlations were changing during the growing season.