Use of Pasteurised and N-Organic-Enriched Sewage Sludge (Biosolid) as Organic Fertiliser for Maize Crops: Grain Production and Soil Modification Evaluation

Trough plot-field essay, the effects of two pasteurised-N-enriched sludge loading (3000, 7000 kg ha−1) on Zea mays L. crop were studied for grain production and soil modifica‐ tions evaluation. The results of pasteurised sewage sludge application (Plateau-ASP– Active Sludge Pasteurization-ActiSolids©) showed a more grain production by the two biosolid doses in comparison with mineral fertilization (NPK: 15:15:15, 1270 kg ha−1). The organic fertilization produced 11 tons ha−1 (grain dry matter) by 9 tons ha−1 (grain dry matter) for mineral application. No relationships were found between N and P application and grain production. The bisolid application (just for the large dose) derived in a low pH [with a low-aluminium saturation (%)], and low C: N, C: P and N: P soil ratios too, with a P soil content increment. By other hand, the heavy metal soil contents (Cd, Cr, Cu, Pb, Zn, Hi, Hg) are below Galiza-Spanish legislation levels (DOG 107/2012).