All chemical elements required by organisms are recycled in ecosystems. Decomposers convert detritus and waste into inorganic nutrients that producers can use.
Where high amounts of ammonium ions are present in agricultural areas, gaseous ammonia can be released into the atmosphere. This ammonia can dissolve and be carried across distances and then be deposited through precipitation. In a study of the effects of deposition of ammonium in a forest, soil samples were taken starting at the forest edge next to an open field and moving toward the centre of the forest.
List two sources of the ammonium in the forest soils apart from deposition in rainfall.