Changes in soil pH and nutrient extractability after co-applying biochar and paper mill biosolids

Acidification and metal mobility may present challenges in soil receiving paper mill biosolids (PB). Co-applying biochar PB could help prevent these issues, but its effect must be assessed. The objective of this 224 d incubation study was to evaluate the amending two acidic soils, a clay sandy loam, with types varying pH (PB1, = 7.80; PB2, 4.51) co-applied three rates (0%, 2.5%, 5% w/w) pine (Pinus strobus L.) on macro- (P, K, Ca, Mg) micronutrients (Cu, Zn, Fe, Mn). In both co-applying significantly increased extractable K concentration compared PB-only application, whereas P unamended soil. comparison only, decreased Cu soils Fe loam This showed that can more beneficial agricultural than application alone by supplying nutrients helping toxicity raising pH, especially soils.