Sediment phosphorus dynamics in tile-fed drainage ditches

摘要

Stream sediments may regulate aqueous phase phosphorus (P) concentrations The objectives of this work were to study the equilibrium P concentrations between the aqueous phase and sediments in tile-fed drainage ditches Sediments from three ditches in Indiana, USA, were sampled and evaluated as P sources or sinks. Sediments that potentially release P to aqueous solutions could be chemically amended to sequester labile P. Sediment deposition from episodic storm events could increase the P buffering capacity of drainage ditches In fluvarium studies (initial concentration of 0.55 mM P), aqueous P concentrations after 120 h were 0.075 mM and 0.111 mM for pre-dredged and dredged sediments, respectively. Phosphorus release from sediments to the aqueous solution was greater from the dredged sediments. These studies are expanding our understanding of the dynamic nature of P in agricultural ditches, and aiding in the development of ditch management practices to reduce downstream P transport.