15N enrichment in organic fertilizers for experimental purposes. 1

In order to obtain organic fertilizer of animal origin the preparation of fodder enriched with 15N is necessary. Using 15NH415NO3 with a relative 15N abundance of 50 at% as a fertilizer, beets, hay and oats grain and straw are prepared for experimental feeding of a dairy cow. As a result of 15N dilution and loss of N out of the 105.5 g of 15N applied to the fertilizer 44.0 g of 15N are contained in the fodder used for the experiment and the production of liquid manure. (author)