Oilseed straw
As oilseeds straw after the are harvest various oil seeds such as rapeseed ( Brassica napus ), sunflower ( Helianthus annuus ), and flax ( Linum usitatissimum ) referred to in the field remaining stems residues as by-products or crop residues as herbaceous biomass are incurred.
Emergence and recovery
In Central Europe, oilseeds are one of the most widely cultivated agricultural crops after grain ; in Europe they are grown on around 16% of the total arable land. The rapeseed represents the main area, which in Germany is around 1.4 million ha and occupies 13% of the arable land (2006) while the sunflower, the second most common oilseed in Europe, occupies only around 32,000 ha.
The grain-to-straw ratio of rapeseed is around 1: 2.9, so that with an average grain yield of around 3.5 t per hectare and year, theoretically 10 t of harvest residues in the form of rapeseed straw remain on the field. A large part of these residues consists of fine fruit stalks and threshed pods that remain between the harvest stubble and cannot be picked up technically. The maximum recovery rate is accordingly around 50 to 80% of the total plant remains, i.e. around 5 to 8 t / ha of rapeseed straw per year. This results in a usable volume of around 7 million t of rapeseed straw for Germany alone.
In the case of sunflowers, the grain-to-straw ratio is around 1: 4.1, so that with an average grain yield of around 2.5 t per hectare and year, theoretically 10 t of crop residues remain in the field in the form of straw. It can be assumed that the recovery rate will be significantly lower than with other straw goods, but no corresponding experience is available.
use
Rapeseed straw is rarely used for material or energy purposes. However, it can also be used as insulation or bedding in stables , and it can also be burned to generate bioenergy . Rapeseed straw has a water content of 45–60 percent when it is harvested, which means that it has to be dried in the field. It has a calorific value of 18.1 MJ / kg.
Sunflower straw is not used due to the very high water content of the thick stalks and the very high ash content of 10% and other properties that are disadvantageous for combustion. It has a calorific value of 16.9 MJ / kg.
supporting documents
- ↑ a b Martin Kaltschmitt , Hans Hartmann and Hermann Hofbauer (eds.), 2009: Energy from biomass. Basics, techniques and procedures. Springer Verlag, 2nd edition, p. 360, ISBN 9783540850946 .
literature
- Stalk-like biomass: Maisstroh In: Martin Kaltschmitt, Hans Hartmann, Hermann Hofbauer (Hrsg.): Energy from biomass. Basics, techniques and procedures. Springer Verlag, Berlin and Heidelberg 2009; P. 153. ISBN 978-3-540-85094-6 .