The crop rotation
was as follows: summer rye (1996), winter rye (1996/1997),
lupine (1997), winter rye (1997/1998), fallow(1998/1999), alfalfa (1999–2002)
However, data presented in this paper only refer
to the period from spring 1999 to summer 2002 when only
alfalfa (Medicago sativa L.) was cultivated.
At Helmstedt alfalfa
was cultivated between tree hedges on a field 200m×51m in
size (Fig. 2).