Field information day 21 July 2021

23 August 2021 - Published by Cees Meijles
Field information day 21 July 2021

For almost two years, Landkreis Heidekreis, in cooperation with 3N Kompetenzzentrum, the Maschinenring Zeven e.V., the Chamber of Agriculture and 23 committed farmers and biogas plants, tested whether liquid manure and manure could replace maize in the biogas plant. The final report has now been presented to the Lower Saxony Minister for Food, Agriculture and Consumer Protection, Barbara Otte-Kinast.


With a view to groundwater protection and the nutrient situation, the farmers have given a lot of thought to the optimal use of liquid manure and manure in the biogas plants. The nutrients should be used in a climate-friendly manner and the maize areas should be available for other crops. For this change in the input materials, the farmers have to undertake a time-consuming process. They were accompanied by 3N Kompetenzzentrum, the Maschinenring Zeven e.V., the Chamber of Agriculture and the district as part of the project funded by the Lower Saxony Ministry of Agriculture.

“The aim of the investigations was to optimize the use of organic fertilizers in the region and at the same time to minimize the use of mineral fertilizers. The increased use of farm manure in biogas plants reduces the space required for maize production, ”explains Ulrike Jungemann, who is in charge of the project at the district.

In the first step, extensive inventory surveys were carried out on the 23 companies: which substrates go into the biogas plant and how many nutrients come back as digestate? How many storage containers are already available and which can be used for the excess quantities? Due to the last dry summer, the corn harvests were not as productive as in previous years. Therefore, additional sampling of the maize silage was analyzed in order to obtain detailed nutritional values.

“Each participating company focused on its own operating concept and had transparent nutrient analyzes of the input and output materials carried out. A total of almost 500 samples were taken, analyzed and evaluated,” reports Sascha Hermus from 3N Kompetenzzentrum in the presentation of the results. In detail, weather data was related to crop yields and losses, with the aim of presenting largely realistic nutrient quantities with which one can present a nutrient management system geared to the farm in the future.

Plant managers Uwe Ringen, Christian Wellenbrock and Andreas Lünzmann presented in detail using their own operating concepts that the required liquid manure processing and the additional amount of manure can also be implemented economically.

Steps for the future

“The project has shown how important the detailed nutrient analyzes are for the operation and future legal changes to the biogas plants and the agricultural operation. A precise declaration of the nutrients obtained is of great importance for downstream marketing and offers the biogas plants the opportunity to act as a hub for nutrient production, ”emphasized Minister Otte-Kinast. "With a view to the European requirements for climate protection, which flow into state law, the biogas plants must focus on the future with more farm manure than input in biogas plants", said the minister.

“In order to be able to meet these requirements, the corresponding increased use of farm manure must be easier in terms of licensing law. This means that storage capacities have to be approved through the use of empty (liquid manure) containers and measured nutrient values have to be accepted and recognized for the recycling concept, ”demanded Ralf Schomacker from Maschinering.

With a view to the future and the achievement of climate targets, biogas is an important energy source and the increased use of farmyard manure is an elementary component. Therefore, the continuation of the project is of great importance. A concentration on a few farms with a monitoring of the previous results and findings in cooperation with the responsible fertilizer authorities and testing services is conceivable. Together, discrepancies in the nutrient values are to be transferred into a future secure nutrient management.

Building a new plant

The biogas plant in Benefeld has been under construction since the end of 2020. At the turn of the year 2022, biomethane will be fed into the grid as a first step and the digestate in the composting plant opposite will be upgraded. The surrounding industrial park energy and environmental park leaves enough space for many innovative development steps into the future.