Corn stalks

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Bundles of corn stalks in Minnesota

As corn stover after the are crop of maize ( Zea mays remaining on the field) leaves, stalks and corn cobs referred to as organic volumes in agriculture as by-products or crop residues as herbaceous biomass are incurred. Corn stalks are only obtained after the harvest of grain maize and grain-spindle mixtures ( Corn-Cob-Mix , CCM), while when using energy maize for the production of maize silage, the entire plant is used. Corn stalks form an important lignocellulose-containing biomass for the production of ethanol or platform chemicals .

Availability

Corn is the most important agricultural grain crop and is used worldwide from tropical to temperate climates. The availability of maize stalks depends on the soil conditions, the topography, the crop rotation and the environmental conditions. The amount of corn straw that can be sustainably harvested is limited, as part of the straw has to remain in the field in order to provide adequate protection against soil erosion by water and wind and so as not to overload the soil's carbon and nutrient balance. It is estimated that between 20 and 80% of the corn stalks can be harvested sustainably.

The two main producers of corn and corn stover are the United States of America (USA) and the People's Republic of China . For the USA, corn stover amounts of 200 to 250 million dry tons are given. For China, 200 to 220 million dry tons, of which an estimated 90% will be removed from the field. Quantities of 580,000 dry tons are given for Belgium, of which an estimated 290,000 dry tons can be harvested economically. For Germany, annual quantities of 3.8 million tons of dry matter are given, which, however, have not yet been harvested.

Emergence, recovery and use

The grain-to-straw ratio of grain maize is around 1: 1.3, so with an average grain yield of around 6.8 t per hectare and year, theoretically 9 t of harvest residues in the form of maize stalks remain on the field. Due to the harvesting technology , the actual amount of residue is likely to be significantly lower. As with other straw fractions, especially cereal straw, a large part of the resulting amount of straw remains chopped up on the field as a humus-forming substrate.

A material or energetic use of corn stalks rarely occurs. This is due, on the one hand, to the limited recovery of maize straw and to the high water content of the harvested biomass, which would require extensive drying of the thick stalks for processing. In some regions, corn stalks are dried in bundles in the field after harvest and can then be collected and used. In terms of its fuel properties, however, dry corn stalks hardly differ from cereal straw, it has a calorific value of 18.9 MJ / kg and a calorific value of 17.7 MJ / kg.

Maize straw offers a model substrate that is widely used for pretreatment experiments, such as steam pressure digestion or steam pressure refiner digestion . The use as a biogas substrate is also described in the literature.

supporting documents

  1. ↑ a b c d e Thomas Berchem, Olivier Roiseux, Caroline Vanderghem, Arnaud Boisdenghien, Guy Foucart, Aurore Richel: Corn stover as feedstock for the production of ethanol: chemical composition of different anatomical fractions and varieties . In: Biofuels, Bioproducts and Biorefining . tape 11 , no. 3 , 2017, p. 430-440 , doi : 10.1002 / bbb.1755 .
  2. ^ WW Wilhelm, Jane MF Johnson, Douglas L. Karlen, David T. Lightle: Corn Stover to Sustain Soil Organic Carbon Further Constrains Biomass Supply . In: Agronomy Journal . tape 99 , no. 6 , 2007, p. 1665-1667 , doi : 10.2134 / agronj2007.0150 .
  3. ↑ Kiran L. Kadam, James D. McMillan: Availability of corn stover as a sustainable feedstock for bioethanol production . In: Bioresource Technology . tape 88 , no. 1 , 2003, p. 17-25 , doi : 10.1016 / S0960-8524 (02) 00269-9 .
  4. ↑ Shengguo Zhao, Guodong Li, Nan Zheng, Jiaqi Wang, Zhongtang Yu: Steam explosion enhances digestibility and fermentation of corn stover by facilitating ruminal microbial colonization . In: Bioresource Technology . tape 253 , 2018, p. 244-251 , doi : 10.1016 / j.biortech.2018.01.024 .
  5. ↑ a b Monika Fleschhut, Martin Strobl: Kornstroh - a substrate that raises hopes . In: Biogas Journal . No. 2 , 2017, p. 26-33 .
  6. ↑ Martin Kaltschmitt , Hans Hartmann and Hermann Hofbauer (eds.), 2009: Energy from biomass. Basics, techniques and procedures. Springer Verlag, 2nd edition, p. 360, ISBN 978-3-540-85094-6 .
  7. ^ Rohit Datar, Jie Huang, Pin-Ching Maness, Ali Mohagheghi, Stefan Czernik, Esteban Chornet: Hydrogen production from the fermentation of corn stover biomass pretreated with a steam-explosion process . In: International Journal of Hydrogen Energy . tape 32 , no. 8 , 2007, p. 932-939 , doi : 10.1016 / j.ijhydene.2006.09.027 .
  8. ↑ Malte Jörn Krafft, Marie Bendler, Andreas Schreiber, Bodo Saake : Steam Refining with Subsequent Alkaline Lignin Extraction as an Alternative Pretreatment Method to Enhance the Enzymatic Digestibility of Corn Stover . In: Agronomy . tape 10 , no. 6 , 2020, p. 811 , doi : 10.3390 / agronomy10060811 .

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 .