Research project "Horse manure"

Experiments to increase N-concentration in horse dung by Azotobacter

Partner:   M4 Bio GmbH & Co. KG Bötzow Oberkrämer (GER)

Funding:  M4 Bio GmbH & Co. KG Bötzow Oberkrämer (GER)

Duration:  June 2015 - July 2016

Project description:

The use of horse manure as fertilizer and soil conditioner is linked to certain boundary conditions, such as the existence of a corresponding sales market.  Currently, farmers can supply their fields with mineral fertilizers more easily and at lower cost. The use of horse manure as fertilizer is an inexpensive alternative. However, this requires appropriate certification as a biofertilizer in cooperation with organic associations. The associations are interested in a biofertilizer with a high fertilizer value and a positive influence on soil properties. This requires an increase in the nitrogen content of horse manure. The natural proportion of about 1.2 to 1.8% by weight of nitrogen in horse manure is not sufficient, especially since up to 25% of the nitrogen is lost during storage and composting. The Institute for Waste and Recycling Management at the Technical University of Dresden is carrying out experimental work to determine how nitrogen enrichment can be achieved. A literature study and practical investigations largely ruled out the possibility of cultivating free-living nitrogen-fixing bacteria (such as Azotobacter sp.) on horse manure, which was originally envisaged. Other ways of nitrogen enrichment had to be found. First successes were achieved with sufficiently ventilated incubation, avoidance of heating the substrate beyond 40°C and promotion of the growth of fast-growing higher fungi.