Agriculture Reference
In-Depth Information
Maize
Sugar beet
Winter wheat
Winter barley
> 50 plants / m
2
0 - 5
5 - 20
20 - 50
Fig. 10.10
Distribution of fi eld violet (
Viola arvensis
) in maize, sugar beet, winter wheat and
winter barley in a 5 ha arable fi eld at Dikopshof Research Station near Bonn, Germany (Modifi ed
after Krohmann et al.
2002
)
Krohmann et al. (
2002
) studied the dynamics of weed seedling distribution over
5 years in a rotation of maize, sugar beet, winter wheat and winter barley and in
continuous maize. They found that
weed distribution maps
obtained in maize and
sugar beet were suitable for site-specifi c weed control in winter wheat and winter
barley (Fig.
10.10
).
Ritter and Gerhards (
2008
) reported that populations of blackgrass (
Alopecurus
myosuroides
) did not signifi cantly change in density, location and size when site-
specifi c weed control methods were applied over a period of 8 years in a rotation of
winter annual cereals, maize and sugar beet. In all of the three fi elds studied,
weed
seedling distribution
was heterogeneous. Density was higher in maize and sugar
beet than in winter cereals. High density patches with densities higher than 25 plant
per m
2
consistently recur over the years at the same areas in the fi elds.
Weed den-
sity reduction
due to herbicides and other weed control methods was satisfying in
each year indicating that site-specifi c weed control methods are sustainable for
long-term weed suppression. Herbicide savings with blackgrass (
A. myosuroides
)
ranged from 50 % in sugar beet to 75 % in winter barley.
Ritter and Gerhards (
2008
) also studied weed
population dynamics
of catch-
weed (
Galium aparine
) and blackgrass (
A. myosuroides
) under the infl uence of site-
specifi c weed management. Most of the tested population parameters were weed
