Many organically managed farms in Europe have low levels of soil phosphorus (P). Arable farms that rely strongly on biological nitrogen fixation (BNF) have been shown to have rather low outputs and a tendency to deplete soil P and potassium (K) compared with arable farms that have a lower reliance on BNF and higher external inputs. Therefore, research focusing on providing a balanced input of nitrogen (N), P, K and sulphur (S) from alternative sources is of interest to organically managed farms in Europe.