Abstract :
Yield mapping is a major component of precision farming. In contrast to the yield mapping available on the market in combine harvesters, yield mapping in forage harvesters is still in the research and development stage. The principles known from the specialist literature are based either on measuring the mass flow or the volume flow. The subject of this paper is improvement of the measuring accuracy of the principle of measuring the width of the gap between the feed rolls of a forage harvester by taking into account the material behaviour of selected typical forage crops (forage rye, pasture grass, spring barley, silo maize). On the basis of compaction experiments under defined laboratory conditions, regression equations are drawn up which can be applied to describe the material behaviour for the pressure area from 0 up to 3·5 bar. The result is a universally applicable algorithm for more accurate throughput measurement, which can be realized in the on-board computers of modern forage harvesters.
