Low-tillage farming would protect agricultural soil. Research by Rainer Horn of Kiel University and colleagues elsewhere has found that crop yields fall by around 80 per cent after six passes with a tractor - which exert a force of five tonnes at each wheel.
Plants become unable to push roots into the compacted soil nor can water penetrate the subsoil.
Horn estimates that 30 million hectares in Europe are completely degraded by soil compaction. Low tillage farming, where the soil is broken up to a depth of only 8 centimetres, with mulch spread on top to control weeds, protects soil and cuts costs. It is increasingly used in America. Or the giant Dowler tractor can be used, which is wider than a tennis court. Some researchers advocate that farmers should be paid to switch to low tillage. '30 million hectares in Europe are completely degraded by soil compaction' You can give a rating to this scheme overall.