One consequence of the BSE-crisis is, that animal residue derived N-fertilisers used in organic horticulture are to be replaced. As an alternative plant derived N-fertilisers have been investigated. In an incubation experiment these fertilisers mineralised 40 to 60 % of the total N applied. Net N-mineralisation in the incubation experiment as well as plant N-utilisation in a pot experiment were closely related to the N-content of the fertilisers. Fertilisers increased the N-uptake of plants in any soil. Neither texture nor the content of Corg explained the observed differences in fertiliser use efficiency
