Reply #1: Yes [View All]

[izquierdista]

Tropical soils tend to be poor in organic matter and nutrients because of the fast rate of decomposition. Areas with fertile black soils, like Iowa and the Ukraine are frozen over for much of the year and the organic matter is not broken down quickly.

I couldn't follow your link, but if the experiments were done in Sweden the temperature effect probably explains it. Charcoal in humus rich cold soils acts to increase surface area available for bacteria to grow, increasing the rate at with they decompose organic matter.