Agriculture Reference
In-Depth Information
content of 8-10 % would be suffi cient for shallow cultivation. However, until now
this interaction is not included in a control algorithm that is state of the art.
It is generally recommended to use this site-specifi c cultivation system only with
soils that do not have compacted zones. The advice therefore is to start with this
system after a fi rst deep cultivation of the whole fi eld under dry conditions.
In principle, such a system is feasible with many different cultivation tools.
Differentiating between primary- and secondary cultivation in this respect might
make sense in humid climates. Yet this distinction hardly helps under dry condi-
tions, where the depth of cultivation might not substantially go below the level of
the seedbed.
7.2.2.2
Economics
Provided the soil is not uniform within a fi eld, which is the rule, the savings from
site-specifi c cultivation in a humid climate can justify the additional investment
needed for the depth control. This is the result of a study by Hartung and Druecker
(
2009
) as well as by Isensee and Reckleben (
2009
) undertaken in Northern Germany
on rolling fi elds and soils of glacial origin.
The site-specifi c cultivation was done with the technology and the equipment as
explained in Figs.
7.4
and
7.5
. The depth of the primary cultivation was mostly
either 20 or 10 cm, since for a more gradual control system no information existed.
The result of the depth control system was that on the average approximately half
the area was cultivated shallow.
The
benefi ts
realized from the site-specifi c primary cultivation were 6
€
per ha
in fuel costs and 2
per ha.
At fi rst sight this sum of benefi ts may seem trivial. However, the total charge includ-
ing labor cost for primary cultivation by tined implements according to contractor
rates is about 25
€
per ha from the increased work-rate, thus a sum of 8
€
per ha. Hence the benefi ts in fuel costs and from the increased
work-rate amount to about 32 % of the usual contractor expenses. In the long term,
these benefi ts can easily cover the additional costs for the control needed.
There were no signifi cant effects of this site-specifi c primary cultivation on the
yields
of small grains (Sommer and Vosshenrich
2004
; Isensee and Reckleben
2009
).
It can be expected that this cultivation method reduces the decomposition of the
soil organic matter because of less aeration at locations where deep work is not
needed. However, this benefi t of site-specifi c operation is diffi cult to evaluate.
€
7.3
Secondary Cultivation
Except for sandy fi elds or for soils high in organic matter content, usually some
clod
break-up
by secondary cultivation is needed for a good crop emergence. In a cloddy
soil, the seeds do not get close contact with the soil water, hence the germination is
reduced. Figure
7.6
shows the emergence of small cereals depending on the mean
