View article

For efficient grassland management, information on the spatial variation of the crop within fields is of the utmost importance. Currently, this mainly depends on qualitative expert knowledge. Quantitative information on the actual status of grass swards at the right moment in the season is important for management decisions, like nitrogen supply, water supply or harvesting.

Remote sensing has proven to be a useful technique for estimating and mapping the spatial variation of various biophysical variables. A whole range of vegetation indices has been developed for estimating variables like biomass, leaf area index and the fraction of absorbed photosynthetically active radiation for a range of vegetation types. However, calibration of the image data is crucial in the performance and applicability of this technique.