Organic wastes like animal manures, sewage sludges, composts, or fermented harvest residues are increasingly produced and recycled in agricultural landscapes all over the world. In a countermove, the areas for food production significantly decreased during the last decades due to increasing agricultural productivity. As a result, the agricultural areas taking up the increasingly produced wastes for recycling are decreasing. The microorganisms introduced to the agricultural soils by wastes may cause shifts in the composition of the autochthonous soil microflora and fauna and eventually change soil functioning.