Agriculture Reference
In-Depth Information
Fig. 7.13
Setting a moisture line in a fallow fi eld by an under-cutter. The
insert
shows the main
tool. The soil surface is covered with anchored crop residues (Photo from Schillinger, altered)
Yet leaving an anchored protection is possible, if the soil is not tilled at all at the
surface and weed control completely left to herbicides. Setting a moisture line still
would be necessary to reduce evaporation from the fallow land (Zaikin et al.
2007
).
This can be achieved by an implement, which just cuts the soil well below the surface
in a horizontal direction, but hardly breaks it up vertically. Such an implement is the
under-cutter
(Fig.
7.13
). Its main tools are wide, horizontal blades, which cut
through the soil about 10 cm below the surface. The soil surface with anchored pro-
tection against erosion is almost left undisturbed. Petrie (
2009
) has shown that for
winter wheat after summer-fallow the combination of once undercutting in the spring
followed by herbicide applications for weed control was as effective as several times
rod weeding during the fallow period in terms of water conservation and grain yields.
So this combination of undercutting and chemical, site-specifi c fallowing deserves
attention in dry-land regions. It protects the soil in two ways. Firstly, it prevents ero-
sion effectively. Secondly, because this combination widely eliminates cultivation,
less soil organic matter is decomposed. This weighs heavily in dry-land areas, since
the effect of cultivation in reducing the soils organic matter is much more pronounced
in dry and warm areas than in humid regions with lower temperatures.
7.5
No-Tillag e: Prerequisites, Consequences and Prospects
The prerequisites as well as the prospects for no-tillage practices depend largely on
the precision exerted in farming. An important trigger for the interest in no-till has
been and still is the development of effi cient and competitive herbicides. Without
these, the present use of no-till practices -
e.g.
on soils with a high organic matter
content - would not be possible.
