Field studies on the value of nutrient-enriched biosolids granules as amendments for winter cereal crops

Abstract. Field-scale experiments in four crop seasons established the agronomic performance of biosolids-derived organomineral fertilizers (OMF) for winter wheat production in England. Two OMF formulations known as OMF₁₀ (10:4:4) and OMF₁₅ (15:4:4) were compared with urea and thermally-dried biosolids granules (≈5:6:0.2) to determine fertilizer effects on crop responses. Fertilizers were applied at N rates between 0 and 250 kg ha^-1 at regular increments of 50 kg ha^-1 N. Average grain yields with OMF₁₀ and OMF₁₅ were higher than with biosolids granules, but lower than with urea (P<0.05). The optimum N application rates, and corresponding grain yields, were 245 and 7900 kg ha^-1 for biosolids, 257 and 9100 kg ha^-1 for OMF₁₀, 249 and 9500 kg ha^-1 for OMF₁₅, and 225 and 10350 kg ha^-1 for urea, respectively. Grain-N recoveries for N inputs equivalent to the optimum rate were 31% for biosolids, ≈40% for OMF and 52% for urea. The use of OMF for winter cereal production appears to be a sustainable approach to recycling biosolids to land.