Laboratory investigation of organic matter mineralization and nutrient leaching from earthworm casts produced by Amynthas khami

▶ This study shows that casts produced by Amynthas khami in Northern Vietnam have a more simplified organization than the surrounding soil aggregates. ▶ Cast fragmentations lead to a progressive leaching of nutrients and to the production of small size aggregates <500 μm in which SOM is protected against decomposition. Conversely, control aggregates were rapidly broken down into 500-5000 μm water stable aggregates and then into <500 μm water stable aggregates. ▶ The aggregate hierarchy concept was not confirmed in the control soil because more C was observed in the smaller aggregate size fractions. ▶ The total amount of N-NH4+, N-NO3−, K and P losses were respectively 8, 7, 12 and 2 folds more important from casts than from the control soil aggregates.