You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
English Issue<br />
Biogas Journal<br />
| <strong>Autumn</strong>_<strong>2017</strong><br />
Grain maize stover –<br />
A substrate that<br />
inspires hope<br />
Cultivating grain maize yields grain maize stover<br />
without any extra effort. Because the stover is<br />
waste, there are many good reasons to use it as a<br />
biogas substrate. But how is maize stover harvested<br />
and what kind of yield is produced? Can the substrate<br />
actually be silaged? Are reasonable methane<br />
yields obtained from fermentation and is using<br />
stover worthwhile from an economic perspective?<br />
The Bavarian State Research Center for Agriculture<br />
(LfL) is answering these questions in a research<br />
project extending over several years. The results so<br />
far definitely inspire hope.<br />
By Monika Fleschhut (M.Sc.)<br />
and Martin Strobl (Dipl.-Ing. agr.)<br />
Photos: Monika Fleschhut<br />
In Germany, the cultivation of grain maize results in 3.8 million<br />
tonnes of maize stover dry matter each year, which have<br />
not been harvested up to now. Instead, the dry matter remains<br />
on the fields for humus production and to return nutrients to<br />
the soil. In comparison, 12 to 14 million tonnes of silo maize<br />
dry matter are used in German biogas plants. Suitable amounts<br />
of maize stover are evidently available, offering true potential for<br />
substitution in terms of quantity. As a waste product, the substrate<br />
is obtained without using any land area and, as a result, is<br />
not associated with any land use competition. Because no effort<br />
is required up until harvest time and because the substrate does<br />
not compete with any other use, grain maize stover is per se very<br />
inexpensive.<br />
Whereas the recovery of the stover is often associated with cultivation<br />
problems, there are also many advantages: Particularly in<br />
crop rotations with a large percentage of grain maize, removing<br />
grain stover can make stover management and soil cultivation<br />
for the next crop rotation easier, while reducing the risk of infection<br />
with Fusarium fungi or European corn borers, for example. If<br />
the digestate is spread out again after fermentation in the biogas<br />
plant, the cycle is closed, to a large extent.<br />
Because maize stover is also not included in the “maize and grain<br />
cap” (Sec. 39h, German Renewable Energy Act [EEG] <strong>2017</strong>),<br />
which limits future use of maize (the entire plant, maize kernel/<br />
spindel mixture, grain maize and husk-cob-meal) and grain to 50<br />
percent by mass – in subsequent years to as low as 44 percent by<br />
mass – at least initially, no legal restrictions on using maize stover<br />
in biogas plants are expected.<br />
12
Change language