Agriculture Reference
In-Depth Information
clay content
organic matter content
hydromorph. situat.
slope & final decision
deep- or shallow cultivation
DGPS receiver
process controller
primary cultivation
secondary cultivation
online depth control
Fig. 7.5
Map overlay for a site-specifi c depth-control of primary cultivation (Vosshenrich and
Sommer
2005a
, altered and supplemented)
slope, but on crop residues left near the soil surface as well. So for these two factors
the situation might vary over time.
There are fi elds where neither hydromorphic soil nor prevention of erosion need
attention, and only a varying clay- and organic matter content remain as control fac-
tors. Both factors can be recorded online and on-the-go. So principally a control in
real-time would be possible (Vosshenrich and Sommer
2005b
). However, for most
cases it seems reasonable to control by
georeferenced maps
instead of employing
a real-time system. Because a dual-map overlay control system - once created - can
be used for many years.
But what means deep- or shallow cultivation in absolute terms? Vosshenrich and
Sommer (
2005a
) defi ned 20 cm for deep- and 10 cm for shallow cultivation. These
absolute depths refer to Northern German conditions. As outlined above, the respec-
tive climate should be considered when the local adjustment for deep- and shallow
operation is defi ned in absolute terms.
An
interaction
of the factors clay- and organic matter content concerning the
needed depth of cultivation can be expected. The higher the organic matter content
is, the lower the clay content probably can be, and
vice versa
. This is, because both
factors inherently promote soil break-up without any cultivation. Vosshenrich and
Sommer (
2005a
) state that with an organic matter content of 1.5 % or more a clay
