Field-scale evaluation of biosolids-derived organomineral fertilisers applied to ryegrass (Lolium perenne L.) in England

A field-scale experiment was conducted to compare the suitability of two organomineral fertiliser (OMF) formulations (OMF- 10: 4: 4 and OMF- 15: 4: 4) with urea and biosolids granules applied to perennial ryegrass. Results showed a 25% to 30% increase in dry matter yield (DMY) with application of OMF compared with biosolids granules but about 5% lower than urea. For OMF, an average input of 0.8 × N max yielded 0.98 × DMY max which was similar to that of urea; whereas, for biosolids, a yield of 0.92 × DMY max required an input of 0.6 × N max but DMY was lower (P 0.05), in soil extractable P. The application of OMF at rates which do not exceed the optimum N rate for the grass crop should not induce significant changes in soil P Index including application to soils with satisfactory P levels. OMF application strategies are discussed which will enable minimising environmental concerns and maximising fertiliser use efficiency