Agriculture Reference
In-Depth Information
But there is also an important development of the past decades, which constrains
no-till. It is the increasing use of heavy farm machinery. Especially on wet soil, this
machinery induces soil compaction. The use of wide, low-pressure tires alleviates
the problem only partly. The situation often is that cultivation has to correct the
damage that was exerted on wet soil in previous operations,
e.g.
during harvesting.
It is possible to inform the farmer via an online sensor whether his machinery is
compacting the soil in an undue way. A
fi eld-traffi cability-sensor
indicates the
depth of sinkage of the tires and thus can inform the operator on-the-go about the
site-specifi c situation (Brunotte
2007
). However, what are the options when a farmer
realizes that his machine is damaging the soil? It is very unlikely that he will stop a
harvesting operation: the soil might be even wetter after having waited a few days.
The farmer is better informed about the situation, yet his options are rather limited.
One option - however - generally is reasonable. In case the farmer is operating the
machine with an infl ation pressure of the tires, which is too high for fi eld use and
should have been adjusted before starting the work, he can correct this.
A challenging approach to solve the compaction problem with heavy machinery
is the “
Controlled Traffi c Farming
” concept (Chamen
1998
; Chamen et al.
2003
).
It is based on the experience that normally plants grow better on non-traffi cked soil
and wheels run better in tracks. Consequently, cropping areas in the fi eld are strictly
separated from wheel lanes. This means that the same wheel tracks are used for
every sowing-, fertilizing-, spraying- as well as harvesting operation, and this year
after year. Since compaction by wheels in the cropping area does not occur any
more, tillage can be omitted and no-till practices can be used. Despite the area lost
because of the tracks, higher yields can be obtained than with conventional farming
(Chamen et al.
2003
; Kelly et al.
2004
; Tullberg et al.
2007
). Precise maneuvering
is essential, yet this is easy to provide by GPS guidance systems.
The agronomical advantages of this concept are striking. However, the conse-
quences for the machinery and its management can create problems. The running
gears of all tractors and machines should be able to use the same tracks. Only small
deviations in the track widths are possible as a result of differences in tire widths
(Fig.
7.14
, top). In case wagons or trucks are loaded on-the-go from the harvesting
machines and not at special places on the headlands, their track width too must be
adapted.
A precise track use is not possible with round trips in the fi eld. Instead driving up
and down is needed - preferably along the longest side of the fi eld. This is no prob-
lem in fl at areas. But this driving pattern does not fi t well to rolling areas and espe-
cially not to contour farming practices. Furthermore, the system does not allow
random turns within the fi eld. So any loading vehicles irrespective of the fi lling
level should not leave the lane before arriving at the headlands.
Adapting all implements to the same track width is not easy because of the
wide
tracks
of present day high capacity grain combines. Their track width exceeds that of
modern heavy tractors by about one third. Technically, enlarging the track widths of
tractors and trailers is possible. Yet problems arise in densely populated countries from
public road-traffi c regulations for tractors and trailers on such wide tracks. It is mainly
for this reason that controlled traffi c farming with tractors, trailers and combines
