Introduction of optimised management concepts to reduce nutrient loads in the soil in free-range systems of organic laying hens (2015 - 2016)

Laying hen husbandry is of great economic importance for organic agriculture in Germany. With about 10%, it has the highest share of total German production compared to other forms of organic livestock farming. The free-range management of laying hens is an absolute eye-catcher for marketing with pictures of lush green runs on which fully feathered hens cavort. However, the 4 m² minimum regulation, which has been in place since 2000, is proving increasingly problematic, especially when uneven use of the area by the animals leads to local pollution of the soil and plant growth. In the case of laying hen houses that remain on one site for a longer period of time, there is a conflict of objectives: on the one hand, to allow the animals as much run as possible and, on the other hand, to avoid eutrophication of the run, especially with nitrogen and phosphorus, which subsequently leads to leaching or outgassing - at least in the case of nitrogen - and thus contradicts the environmental objectives of organic farming.

In the project, two identical mobile barns are operated in parallel on a practical farm, one mobile, the other stationary. The focus of the investigations is the N-dynamics in the outdoor area. Over two seepage periods, the dynamics of NH4-N and NO3-N will be recorded at four to six week intervals, depending on the different zones. Further investigation parameters are the manure accumulation in the indoor and outdoor area, the P enrichment in the outdoor area and others.

Final report for download: NRW_1_Final_Report_final.pdf.zip