Completed research projects

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Completed research projects

Duration: Oct. 2016 - Dec. 2019

In organic farming (ÖL), conventional biomass can currently be purchased for biogas production, e.g. corn silage, according to the guidelines. This will be prohibited in many ÖL associations from 2020. Therefore, it is necessary to develop other options for biomass production that do not compete or compete only slightly with cash crop or forage production, as these will continue to have priority in ÖL. To this end, the research project will investigate three strategies, each with several variants, in terms of their growth dynamics and biomass yields:

1) Optimized intercropping after threshing crop: spring cereal oats in pure or mixed cropping with legumes (peas) for biogas production; clover grass as undersowing for biogas production.

2)     Field forage cultivation: use of 3rd and possibly  4th growth for biogas production - clover-grass, alfalfa-grass, Landsberg mixture

3)     Two-crop use for whole-crop silage production: optional use of first (EK) or second (ZK) crops for forage or biogas production; combinations EK/ZK: rye-winter peas/maize,triticale-winter peas/oats, rye/clover grass.

Furthermore, quality and biogas parameters are collected or calculated and synergy effects regarding water, soil and climate protection as well as nitrogen fixation are evaluated.

The field trials at the Neu-Eichenberg site will be carried out over three vegetation periods.

Funded by the BMEL via the project management organization FNR.

Further information in the project database of the FNR:

Contact: Dr. Rüdiger Graß,

Sustainable intensification in agriculture through agroforestry systems

The joint project SIGNAL as part of the funding program BonaRes (Soil as a Sustainable Resource for the Bioeconomy) investigates over a period of up to 9 years the effects of agroforestry systems on the biological functions of the soil, the rhizosphere, the above-ground material fluxes as well as the water use efficiency of the soils. The basis of the research approaches within the project is the central hypothesis that innovative land use systems consisting of coupled cultivation of trees or shrubs with crop or pasture plants (agroforestry systems) can show positive ecological, economic and cultural effects in contrast to conventional crop production systems.

The scope of the GNR department of the University of Kassel/Witzenhausen within the collaborative project is to evaluate the effects of different management strategies on above-ground material fluxes in agroforestry systems. The experimental areas already established in 2011 within the framework of the joint project BEST ("Strengthening bioenergy regions - new system solutions in the area of conflict between ecological, economic and social requirements") as well as the scientific knowledge gained offer the best conditions for answering the given questions. The test areas are located in southern Lower Saxony on an area of approx. 1.3 ha.

The agroforestry system consists of alternating 80 m long rows of pasture and grassland in threefold repetition. The 9 m wide grassland strips were established with three different seedings (pure grass, clover-grass and a biodiversity mixture with 32 species). The grassland is used by cutting 2 or 4 times.

Between the grassland strips, willows ((Salix viminalis x Salix Schwerinii) x Salix viminalis = Zuechtung Tora x Z. Ulv) are planted over a width of 7 m. Their bushy growth makes them particularly suitable for use with short rotation. The woody plants have a rotation period of 3 years, and the first clearing of the pastures took place in winter 2014/15. During the first rotation period, no significant economic advantages of SRC over conventional systems could be demonstrated (see references), which is not surprising due to the short establishment of the agroforestry system. Therefore, the medium- to long-term biomass growth is of particular interest. In addition to the economic potential, the long-term effects of short rotation coppice under different grassland use intensity and seeding on ecological parameters, such as nitrogen and phosphorus fixation, nutrient availability, and water use efficiency of soils, will be determined in particular in the next years together with soil science partners. These long-term findings are important to optimize the planning and management of such agroforestry systems and to provide incentives to rethink conventional cropping systems to ensure the best possible use of limited cropland and to protect soil as a natural resource.


Dr. Rüdiger Grass

Steinstaße 19

37213 Witzenhausen

Phone: +49 561 804-1312

Sarah Malec

Steinstrasse 19

37213 Witzenhausen

Tele.: +49 561 804- 1338






Federal Ministry of Education and Research 


Ehret M., Bühle L., Graß R., Lamersdorf N., Wachendorf M. (2015): Bioenergy provision by an alley cropping system of grassland and shrub willow hybrids: biomass, fuel characteristics and net energy yields. Agrofor. Syst. 89, 365-381

Ehret M., Graß R., Wachendorf M. (2015): The effect of shade and shade material on white clover/perennial ryegrass mixtures for temperate agroforestry systems. Agrofor. Syst: DOI 10.1007/s10457-015-9791-0.

EIT Climate-KIC: MOO - Farm Coal Innovator

Duration: August 2018 - December 2018

Farm Coal Innovator (MOO) is a research project investigating the suitability of biomasses with lower feed value (e.g. landscape maintenance material, residual biomasses, etc.) from cattle farms for the production of bio-based activated carbon. Activated carbon is used in various technological processes, mainly for purification purposes, but is also used, for example, in veterinary medicine or to reduce emissions from manure. This is associated with positive effects for various actors along the value chain:- - Utilization of

  • Utilization of biomass that was previously difficult to use (landscape management material, late growth in grassland and field fodder use)
  • Preservation of landscape elements that are valuable from a nature conservation perspective
  • Regional production of sustainable (bio-based and renewable) activated carbon for a variety of applications - creation of a new value chain
  • Consumption of regionally produced activated carbon e.g. by wastewater treatment plant operators.

The MOO project is funded by Climate-KIC (Task ID: TC2018B_4.3.3-FCI_P097-1A), Europe's largest public-private network for innovation against climate change, founded in 2010 by the European Institute of Innovation and Technology (EIT).

For more information on Climate-KIC, visit

MOO Farm Coal Innovator - Agrisource

 The  promotion  concentrates  on  the energetic utilization of the foliage of street trees by means of the IFBB process, among others.  Thereby  investigations  on the optimal  collection procedure  of the fresh biomass  and  their  primary cleaning  are carried out,  so  that  the  coarse  particles (fine dust,  sand  and  others) from the foliage surface do not complicate the energetic recovery process and do not end up in the energetic conversion plant.  

The PhD aims to increase both the ecological and economic value of autumn leaves through IFBB technology. The following questions will be addressed: 

1.  How can the foliage be optimally collected, cleaned and stored for IFBB technology ? 

2.  What is the heavy metal load of tree foliage on roads with different traffic density? 

3.  What are the  differences  between  the  conditioning temperatures  (40°C,  60°C,  80°C)  and what are the mass flows of the substances as a function of temperature?  

4.  What is the total energy value of the IFBB process compared to direct incineration and what is the economic and ecological value (CO2 savings) compared to composting?

Duration: 2013-2016

The area under corn cultivation has increased continuously in Germany in recent years, mainly due to its overwhelming importance as a feedstock for biogas plants. However, the increasing cultivation of corn is increasingly seen as problematic for sustainable agriculture. Nevertheless, corn will maintain its prominent position in pure cultivation as a feedstock for biogas plants in the foreseeable future. Therefore, it is necessary to (further) develop cultivation systems and cultivation forms through which maize cultivation can be made more sustainable. The mixed cultivation of corn with beans, as it has been known and widespread in the tropics for a long time, could contribute to this. In the research project, corn and beans with different seed strengths and mixing ratios will be investigated under the conditions of organic and conventional farming with regard to their stand development, biomass yield and methane yield. Furthermore, different variants of mechanical weed control will be tested. The trial will take place at the Neu-Eichenberg (organic) trial site of the University of Kassel and cooperatively at the two conventional sites Tachenhausen (HfWU Nürtingen-Geislingen) and Grub (LfL Bayern).

Funded by the FNR. Further information in the FNR project database under the funding code: 22003712.

Graduiertenkolleg 1397 - Control of humus and nutrient balance in organic agriculture, Subproject A2: Disturbance-free recording of structural and functional stand parameters in heterogeneous pasture systems.

Link to DFG


Joint project: Detection of clone-site interactions in poplar and willow on agricultural sites in short rotation periods - ProLoc (Yield - Program - Locus) - Project Phase II ; Work Package 1 and Work Package 2 (2012-2015).

KURZUM II - Dynamics of soil C fractions and plant productivity during the conversion of short rotation coppice (SRC) to arable and grassland use - short rotation coppice conversion. Continuation of the research project KURZUM (2013-2015/KURZUM II).

DANUBENERGY - Decentralized energy production from biomass of the Danube basin and other river floodplains of Central Europe

Cli­ma­te-KIC In­no­va­ti­on Mu­bi­gen Pa­th­fin­der project aims at creating a potential business model for an integrat-ed value chain, in which cities produce their own marketable and storable energy carriers and biomaterials from unused urban grass cuttings with an innovative technology. The Pathfinder activities will focus on two complementing strands: 1) A joint effort on the regional level with municipal stakeholders, plant manufacturers and academics will demonstrate the potential positive climate impact and prepare the exploitation of the business idea in two different European cities. 2) Detailed preparation of a European network, which transfers the business idea to other European municipalities, connects the participating regions and stakeholders and provides services for a successful implementation of the business idea. Besides these business-model related clarifications and results the pathfinder will create a strong consortium which has on board all necessary know-how to develop a self-sustaining business and exploi-tation plan in an innovation project yet to come.

BEST - Strengthening Bioenergy Regions

Endevelopment and evaluation of adapted cultivation and utilization concepts for energy crops in the area of influence of North Hessian watercourses (R1)

Project sponsor: BMBF

In view of the expected climatic changes in northern Hesse, adaptation strategies for agricultural cultivation and utilization systems are necessary to enable environmentally sound and high-yield agriculture. In the research project, such strategies are developed exemplarily in the catchment and flood area of flowing waters. In the process, arable sites in the catchment area will be recorded that are significant in terms of groundwater and soil protection (key words: substance discharge and erosion). For these sites, cultivation systems for energy crops are investigated with regard to yield and various environmental parameters. In the floodplain of watercourses, grassland stands are investigated as suitable vegetation to ensure water and soil protection functions. In a further focus of work, the data determined in these field tests are used to develop model scenarios for catchment and floodplain areas of the Fulda in northern Hesse against the background of regionalized climate scenarios. The scenarios derived from this will enable transferability to other regions.

Contact person: Dr. Rüdiger Graß

Project duration: 01.04.2013 - 31.05.2014

Joint project EVA III: Development and comparison of optimized cropping systems for agricultural production of energy crops under different site conditions in Germany - Phase III. SP 5: Two-crop utilization system (ÖKOVERS).

Building on the trials in SP 6, in which the two-crop utilization system was tested at 7 sites in Germany, a multi-location start was made in 2007 to cultivate energy crops also under organic conditions for decision support (ÖKOVERS). At the same time, the system experiment was continued in a reduced form (KORB) to consolidate the previous results and for a comparison of the cultivation forms. The current project includes the trial activities in 2013 to complete the 2nd plant of the ÖKOVERS trial as well as the final overall evaluation of the ÖKOVERS trial program in conjunction with KORB. At the locations Haus Düsse, Rauischholzhausen, Straubing and Witzenhausen, the after-effect of different preceding crops and quantities of separated digestate to the preceding crop will be conclusively tested in 2013 in variant 2 (one-and-a-half-year clover grass) using winter wheat. In addition to the yield determination and analysis of the ingredients, detailed ecological and economic accompanying investigations will be carried out in the trials. Parallel to this, as well as after the last harvest, the trial elements will be evaluated in each case over 2 years, in the overall trial as well as between the cultivation systems.

Further information and final project report

FORURB- Towards a water and nutrient efficient forage production in peri-urban and urban livestock farming in Faisalabad, Pakistan

A PhD Thesis in the Framework of the ICDD (International Center for Development and Decent Work)

The agriculture sector plays a fundamental role in Pakistan's economy. It is the second largest sector, accounting for over 21 percent of national GDP. Livestock, the single largest contributor, contributes approximately 53.2 percent of the agriculture value added. Green fodder is the most valuable and cheapest source of feed for livestock. Maintaining the availability of adequate feed for livestock is crucial to smallholders who depend on animals for their livelihood. Fodder constitutes up to 70 percent of livestock inputs and is crucial to the livelihood of poor livestock-keepers. But yield and area under fodder crops is reducing due to the growing pressure of the human population, shortage of irrigation water, less and erratic rainfalls, low priorities for fodder production and imbalanced use of fertilizers. Keeping in view the constraints in fodder production, the  major objective of the study will be the improvement of production and quality of fodder to overcome the gap between fodder production and requirement and improvement in social standards of the people who depends on livestock for their livelihood. First of all, a baseline survey will be conducted in fodder growing areas of Faisalabad to collect data about socioeconomic activities and agricultural production practices of the farmers. On the basis of the survey, field experiments will be conducted to assess the water and nutrient efficiency of different fodder crops. Field experiment treatments will include three fertilizer levels (control, chemical fertilizer and animal manure) and two irrigation levels (recommended irrigation and half of the recommended irrigation). Two fodder types in each season will be evaluated in terms of yield and quality. Fodder types with good water and nutrient efficiency will be recommended for the farmers. Possible outcomes of this research are availability of good quality fodder throughout the year and, ultimately, improvement in social standards of the people.

Project duration: January 2009 - June 2012

In many years of research, the University of Kassel has developed a special technique for the energetic utilization of biomass (production of electricity and solid fuel), which is particularly suitable for older grassland growths.
For the demonstration of the Europe-wide applicability of this technology on NATURA 2000 grassland habitats of particular conservation value, a mobile bioenergy plant will be deployed at three different locations (Germany, Wales, Estonia). The project focuses on socio-economic and business aspects as well as sustainability with regard to the preservation of botanical diversity, climate-relevant savings potentials and the strengthening of regional material and value cycles in remote, economically disadvantaged regions.
One focus of the project is the regional and Europe-wide dissemination of information and the provision of advice to potentially interested parties and users in agriculture, higher-level institutions and interest groups.
Further information:

Project duration: 2005-2008

The project is embedded in an EU-wide research project (COST 852) dealing with the importance of legumes for biodiversity and performance of forage production in Europe. The cultivation of forage legumes plays a central role in organic agriculture. Due to the ability of legumes to fix nitrogen from the air, they provide a valuable contribution for nitrogen supply to the farm cycle. In addition, forage legumes provide a very high protein feed, which is important for performance-based animal husbandry. Red clover, white clover, alfalfa and horn clover with the mixing partners German ryegrass, cocksfoot and chicory are investigated. Relationships between biomass growth, species composition, nitrogen fixation performance, forage quality parameters, and numerous environmental conditions will be documented.

Under field conditions, the botanical composition of grassland stands exhibits a wide range of variation, affecting several important agronomic factors such as forage quality and yield.

Continuous records of legume yield percentages across all subplots of a grassland would increase understanding of nutrient dynamics and allow targeted actions to be taken based on this to manage these plots more efficiently. With the help of field spectroscopic measurements, models are to be developed that make it possible to record the proportion of legumes in a stand on a small scale. The advantage of this method is that the harvesting of the crop would be superfluous, since only the reflection of the incident sunlight on the crop is measured. From the reflection curve, which is typical for each plant stand, the corresponding information should be derived and the proportion of legumes in the stand should be inferred. This could result in a much faster determination of the proportion of legumes in areas and allow this determination to be made more frequently without great effort.

COST Action 852

Influence of biodiversity on the expression and spectral calibration of bioenergetic parameters of smooth oat meadow vegetation

Project duration: 2002 - 2008

The project investigates the relationship between biodiversity and bioenergetic utilization potential on the basis of floristically unambiguously defined stands of smooth oat meadows (Arrhenathereten) and, on the basis of this material, determines the relationship between spectral signatures of the stands and selected bioenergetic parameters.

The basis for the investigation is the "Jena Experiment" of the DFG Research Unit 456 "The role of biodiversity for element cycling and trophic interactions: An experimental approach in a grassland community". Based on the existing diversity gradients of up to 60 species and 4 functional groups the influences of biodiversity on energetic properties are quantified and assigned. As a prerequisite for an efficient estimation of substrate properties for energetic utilization by means of anaerobic fermentation or thermal conversion, spectral signatures will be collected on standing plant stands, on their preserves (silage and hay), and on standardized laboratory samples. Based on this, calibrations will be developed and the potential of the conversion processes will be evaluated.

The project thus develops the basis for a stock-specific utilization management taking into account the entire bioenergetic process chain. The unique experimental conditions of the Jena experiment with its defined diversity criteria enable new fundamental evaluation approaches for bioenergetic utilization of extensive grassland with the adaptation of innovative sensor-based methods. The Jena experiment is complemented by a component with high application orientation with the investigations on the influence of biodiversity on the bioenergetic utilization potential of the stands.

further information: