Agriculture Reference
In-Depth Information
automatic guidance
use of spreader
fertilizers
use of sprayer
pesticides
use of cultivator
manual lightbar guidance
15 000
euros
per
year
11 000
minimum area
for economic use
= 122 ha / year
minimum area
for economic use
= 451 ha / year
9 000
fixed costs / year,
autom. guidance
7 000
5 000
3 000
fixed costs / year,
manual guidance
1 000
300 ha
1000 ha
300 ha
1000 ha annual area
Fig. 4.7
The columns show savings with small grains that can be realized by the reduction of
overlappings when using GPS guidance methods for soil cultivation, for spreading of fertilizers
and for spraying of pesticides. The operational savings for the use of the cultivator, spreader and
sprayer include saved labour costs. The savings for fertilizers and pesticides are based on costs of
respectively 115 and 160 Euros/ha. Any savings for seeds would be small and are not included.
The
dashed horizontal lines
represent fi xed costs of the guidance systems. It is obvious that the
savings can be much higher than the fi xed costs (From Reckleben
2008
, altered)
On the other hand, the overlapping without using GPS guidance was much
lower - only 4.20 % - when fertilizing- and spraying operations were carried out
in
tramlines
. This cross-track error of 4.20 % includes inaccuracies that occurred
when the tramlines were generated during sowing. However, the errors that result
from inaccuracies in the course of tramlines often have a multiple effect. Because
the tramlines are used several times during a growing period for spreading agro-
chemicals. Furthermore, also this error of 4.20 % was still signifi cantly reduced
when GPS guidance methods were used for all operations. With the manual light-
bar method and carrier phase signals plus dual frequencies, the overlapping
dropped to 0.92 %. And when the automatic guidance with RTK-GPS was used, it
went down to 0.10 % (Bombien
2005
; Reckleben
2008
,
2011
). For the respective
cross-track errors in absolute- instead of relative data see Sect.
4.2
.
The
savings
from less overlapping shown in Fig.
4.7
refer to operations for small
grains in Germany. Those for fertilizing and spraying are based on driving in tram-
lines. The main savings come from reduced expenses for fertilizers and for pesti-
cides and not from the improved use of the capacity of the machines (Fig.
4.7
).
Consequently, the savings will increase with the yield of crops and the respective
use of agrochemicals. Any savings in expenses for seeds would be small and are not
included. Yet apart from this, it is obvious that the savings from less overlapping can
be much higher than the fi xed costs from GPS guidance.
The general situation is that the manual lightbar system suits to medium sized
farms and the automatic system to larger farms. Yet special possibilities that are
