Soil and land use effects on phosphorus in six streams draining small agricultural catchments in Scotland

Phosphorus concentrations and outputs have been compared and contrasted in six small agricultural catchments in the west and northeast of Scotland. The loss of P from soils to stream waters was more from catchments a with intensive dairy cattle farming in the west than from the less intensively stocked/arable catchments in the northeast, with striking differences being seen between the two regions. In the northeast, intensive animal farming caused less P loss in drainage water than arable management. Larger mean annual concentrations were seen in the west (0.076-0.142 mg PO4-P/l as molybdate-reactive phosphate-MRP) compared with the northeast (0.012-0.025 mg PO4-P/l), a feature caused by the combination of limited P-retention in the western Gleysols and smaller inputs to the largely-podzolic northeastern catchments. Stream concentrations were decreased by dilution during winter storm flows and increased during summer base-flow and at the beginning of soil rewetting in autumn.