Phosphorus transport through a clay soil

Abstract

Phosphorus (P) losses to surface bodies of water both via surface runoff and via drainage tiles is considered a very important environmental issue because it is the nutrient limiting agent for aquatic vegetation. Therefore, understanding the mechanisms by which P is transported to the aquatic environment is a very vital subject. Movement of phosphorus and bromide (Br) was studied in seven undisturbed soil monolith lysimeters containing clay soil collected at Oxelby near Stockhohn, Sweden. They were exposed to natural climatical conditions for the period 30 November 1993 through 6 May 1996. Drainage samples were collected on a weakly basis and flow discharge was measured at the same time. Results showed that preferential flow processes dominated the loss of Br through all seven lysimeters. Phosphorus losses, mainly in the particulate form, showed high variability and was shown to be flux dominated as well. The results indicated that rainstorms had to reach a certain intensity to initiate total P and particulate P losses which was a proof for dependency of P losses to flux in this heavy textured soil.

Key words:

• Total phosphorus
• particulate phosphorus
• transport
• preferential flow
• macropores
• lysimeters