Leaching of Phosphorus and Cadmium in Soils Amended with Different Bone Chars: Fid-Bau Portal

Leaching of Phosphorus and Cadmium in Soils Amended with Different Bone Chars

Morshedizad, Mohsen / Leinweber, Peter

The benefits of bone char (BC) application may include both the mobilization of P for plant nutrition and immobilization of contaminant Cd in the soil. However, previous studies were conducted under equilibrium conditions that do not adequately reflect field conditions. Therefore, the objective was to study the effect of BC, surface‐modified BC (BC^plus) and sulfur‐enriched activated char (AC^S) application at different particle sizes on P‐ and Cd‐mobilization under non‐equilibrium conditions in a combined incubation‐leaching experiment. Two soils each with the treatments (i) BC, (ii) BC^plus, (iii) BC + AC^S, (iv) control (0 mg P kg⁻¹ soil), and (v) AC^S were leached five times during 70 days incubation. Over the complete incubation P‐contents in leachates were significantly increased by BC and BC^plus of 0.5–1 mm size. P‐release from BCs was larger under non‐equilibrium condition in this experiment compared with a previous continuous incubation experiment. AC^s application reduced the P‐release from BC of all particle sizes. The lowest leachate Cd‐concentrations were found in soils amended with the smallest BC particles. Addition of BC^plus and AC^S significantly increased Cd leaching and the highest amounts of Cd were leached at the smallest particle size. In conclusion, the 0.5–1 mm size class of BCs performed best and should be introduced in practical agriculture using standard machinery.