Organic agriculture erosion, soil

Plant species differ widely in the extent of phosphorus absorption by their roots. Forest trees take up P from insoluble compounds with the help of mycorrhizas, whereas phosphorus is removed from soils by harvested crops ( 6 kg ha in agriculture), erosion and to a small extent by leaching (-0.1 kg ha ) and volatilization as phosphine PH3. In the case of erosion, colloids with their surface-bound P are transported into surface waters, and this leads to the eutrophication of aquatic ecosystems, for example in lakes. Leaching losses occur only in sand and peat soils, and in the case of organic phosphates. Under extreme redox situations - as in some paddy soils - phosphate is reduced to PH3 as a gaseous product. 

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