One morning at the end of July, approximately 250 young people were invited to come to the “Unterer Lindenhof” experimental station to learn that agriculture has three major tasks: “To produce food, animal feed and fuel,” explained Prof. Dr. Wilhelm Claupein, using the English version rather than the German words in order to explain what agriculture is being used for, stressing the new international agricultural concept of the “3 fs”. While it can be assumed that the schoolchildren know that agriculture produces food and animal feed, how agriculture can supply energy is something that had to be explained in more detail. Therefore, the Institute of Crop Production and Grassland Research invited the schoolchildren to participate in a biomass action day that was organised at the Unterer Lindenhof experimental station. The motto of the day was: “A cowpat brings excitement – experiencing biomass in its many forms.”

The experimental station is located in Eningen, which is a small city located at the foot of the Swabian Alb. It is Germany’s first large experimental biogas facility, surrounded by cattle sheds and trial fields. Standing in the shade of parasols, the scientific staff of the Institute of Crop Production eagerly awaited the arrival of approx. 250 8th–11th grade pupils for whom they had prepared a course with six experimental stations. Station one: “A cowpat brings excitement”.

The day's motto focused on showing the schoolchildren how the biogas facility works. Fermentable biomass, such as liquid manure and silage, is used to ‘feed' the biogas plant, in turn leading to the production of methane and carbon dioxide. These are subsequently fed into a combustion process, in turn leading to electricity and heat. Scientists at the Unterer Lindenhof are working on the optimisation of a biogas plant by carrying out "feeding experiments for the biogas plant", said Claupein, explaining the biogas production process to the schoolchildren in an easy way. Numerous measurement options enable information to be obtained on the suitability of different fermentation substrates.

29000 km with one rape field

Station II provided the teenagers with information on biodiesel. Martin Gauder, a doctoral student at the institute, explained what the oil yield that is produced from a 1-ha rape acre can be used for: a 5-l car could drive 29,000 km. However, Gauder also pointed out that the quantity of biodiesel that is produced in Germany is not sufficient to supply all of Germany's cars. The next station focused on "Experiencing biomass in its many forms".

The teenagers were given pieces of bread soaked in oil to taste the different types of oil, including oils with high and low smoke points. They also learned about omega 3 fatty acids and how the different oils are best used. At the next station, Dr. Ulrich Thumm focused on the question of why plants store oil. The teenagers knew the correct answer: "The seeds require energy to be able to germinate." "Sunflowers, oil flax, pumpkins, walnuts, and false flax, all of these plants produce oil. But rape is the most important oil-producing plant," explained Thumm.   

Scientists in charge of the forest located in proximity to the experimental fields showed the ecological advantages of producing heat from wood, including the fact that burning wood releases the same amount of carbon as plants remove from the air, thereby creating what is referred to as a "carbon neutral" process. The scientists also explained that only a limited number of trees are felled - and the area is quickly replanted in order to maintain the same number of trees overall. A column diagram showed how many split logs, wood chips or wood pellets are required to substitute one litre of heating oil. The next station challenged the children to assign seeds to different plants and showed them the different types of silage that are used for fermentation in biogas plants.

The teenagers’ visit to Unterer Lindenhof ended with an entertaining highlight – “sunchoke (Helianthus tuberosus) pigs”. Helianthus is excellently suited for use in a biogas plant. However, these plants tend to continue to grow in fields even when other crops have been planted. To counteract this, the scientists use pigs to eat the tasty tubers.

Sibylle Sachtleben, a teacher at the Hölderlin School in the city of Nürtingen, who brought her 9th grade pupils to Unterer Lindenhof, found the action day very interesting and stated that it offered a broad range of information. The pupils had previously produced biogas in class, and so it was a natural thing for the teacher to also bring her class to the action day. The University of Hohenheim had provided the pupils with informational materials prior to their visit to the experimental station in order to attain some idea of the research being conducted there.

Claupein and his team had 10,000 euro at their disposal to organise the action day. The money was part of the 1st prize that was won by the institute in the “Alltagstauglich” contest that was organised by the German Federal Ministry of Education and Research (BMBF). The action day is one of 15 winning projects, but it was the only one in the area of agricultural sciences.

Further information:
Prof. Dr. Wilhelm Claupein
University of Hohenheim
Institute of Crop Production and Grassland Research
E-mail: claupein(at)uni-hohenheim.de