Autumn 2017 EN

English Issue
Biogas Journal
| Autumn_2017
Silaged sugar-beet pieces from the maize stover silage.
Sugar-beets sweeten
maize straw silage
Fermenting straw, particularly maize straw, is currently a topic of great discussion
and put to practice by some professionals. Initial findings are highly promising.
By Martin Bensmann
Every year inautumn, harvesters roll through
the maize fields and cut down the dry maize
plants while collecting the cobs from the
stalks and threshing the kernels. This means
the entire plants – except for the kernels –
are returned to the field, all chopped up. Up to now,
these large amounts of stover have not been used; they
were grubbed or ploughed in the fields which can result
in problems with land under arable crops.
For example, when ploughing a furrow, a so-called
“straw mat” can result, which can cause trouble. Residual
stover at the soil surface can be infected with
Fusarium fungi, which can cause fungal infections in
subsequent grain crops. In addition, the stover must be
taken fully into account in terms of nutrient content,
which increase the need for nutrient export in regions
with nutrient overloading.
However, because maize straw still contains a certain
amount of energy, it makes sense to ferment it in biogas
plants. An additional advantage of using maize stover in
biogas plants is the mitigation of the aforementionend
problems with land under arable crops. Analyses performed
by the Bavarian State Research Center for Agriculture
indicate that maize stover provides about 80
to 90 percent of the methane yield from silo maize.
According to the German trade association for maize
growers [Deutsches Maiskomitee e.V.], about 416,200
hectares of grain maize, including CCM, were planted
in Germany in 2016.
Grain maize cultivation regionally
very common
Last year, Hermann-Josef Pieper as many was looking
for an inexpensive replacement for silo maize. He is the
managing director of two biogas plants in Dörpen in the
northern part of the Emsland district in Lower Saxony –
BERD und BERDZWO GmbH & Co.KG, an association
of six farmers. “Four years ago we started using sugarbeets
to reduce the percentage of silo maize. We also
tried to use grass silage consisting of mixtures of field
grasses, but due to the large area required and/or high
rental costs, it is not cost-effective”, explains Pieper.
Due to the fact that besides silo maize a lot of grain
maize is grown in his region he started to think in this
direction.
At a conference in Heiden in North Rhine-Westphalia
at the end of August last year, Pieper gathered information
and established an important contact with Dietrich
20