Imaging spectroscopy for characterisation of grass swards.

The potential of imaging spectroscopy as a tool for characterisation of grass swards was explored with respect to growth monitoring, detection of nitrogen and drought stress, and assessment of dry matter yield, clover content, nutrient content, feeding value, sward heterogeneity and production capacity. To this end, an experimental imaging spectroscopy system was developed. The system detects reflection in image lines in the wavelength range from 405-1659 nm with three different sensors at 1.3 m above the soil surface. Spectral resolution varies between 5-13 nm, and spatial resolution between 0.28-1.45 mm2 per pixel at the soil. As a result of system design, reflection intensity is a function of leaf height and leaf angle. The system was tested on mini swards grown in containers. For each mini sward, 42 image lines were recorded in a regular sampling pattern per recording event...