Successful field day on different organic fertilizers

The field day in Nettlingen near Söhlde on May 12, 2023, attracted many interested press representatives, plant operators, researchers, and farmers. The permanent trial of the Julius Kühn-Institute (JKI) in cooperation with the company Kommunalservice Hans Vornkahl GmbH as well as the affiliated work of the Thünen Institute for Agricultural Technology in the project „PiA-Plastics in Agricultural Soil", represented by Daniela Thomas, were shown. The trials will consider, for example, the effects on agricultural soils and crop production of applying organic fertilizers with sewage sludge compost, green waste compost, digestate, dry chicken manure, sewage sludge, and biowaste compost, as well as ready-made fertilizers based on the precipitation product struvite (magnesium ammonium phosphate) from wastewater treatment. In addition, the potential contamination of organic fertilizers with (micro)plastics is investigated. Agricultural fertilization with organic manures and precipitation products from wastewater treatment as well as the contamination of agricultural soils with (micro)plastics are topics of increasing public and scientific interest. Against the backdrop of rising energy prices, the drive to close material cycles, sustainability, and environmental protection, as well as the changing legal requirements for wastewater management, where the recovery of phosphorus is a key component, the topics offered were very well received.

Among others, the following topics were presented in posters:

- Organic fertilization - an alternative to mineral fertilization?

- Struvite - a magnesium ammonium phosphate with the potential for organic agriculture

- How do microplastics get into the soil? - Detection of possible contamination pathways

During the field day, the flowering canola trial was visited, sampling strategies and methods were discussed, and the topic of possible contamination with heavy metals, antibiotic residues, and (micro)plastics was addressed. The input of possible contaminants is an important topic and was discussed comparatively to inputs from mineral fertilization.

The guests' physical well-being was taken care of by the JKI's business partners on site, Kommunalservice Hans Vornkahl GmbH as host, SF-Soepenberg GmbH, and Rapool. And there was plenty of sunshine for free.