Chemical losses off dairy catchments located on a texture-contrast soil: carbon, phosphorus, sulphur, and other chemicals

Level 1 General description

Purpose:

The purpose of this study was to determine nutrient losses from a commercial dairying pasture in both overland flow and A/B horizon interflow.

Methods (brief)

Water samples were collected and analysed for chemical concentrations and loads in runoff water following a storm event from two catchments on adjacent sides of a small ridge (East and West).

Catchments were hydrologically isolated by exclusion drains cut into the subsoil clay around the upper and perimeter areas, and by a stainless steel water barrier installed completely across the bottom edge of each catchment. Surface water reaching the barrier was channelled to a 150-mm RBC flume at the lowest point. A 2-m-wide rectangular overflow weir was fitted alongside each flume. Flumes were instrumented with an ISCO Model 4230 Flowmeter and Model 2700 Sampler.

Key findings (brief)

Over 90% of all C from the East catchment was overland flow. Slightly less (60 - 80%) was present as overland flow on the West catchment. Most P from the West catchment and almost all P from the East catchment were present in overland flow. Overland S loads were slightly lower than P loads, whereas interflow S loads were higher.

Up to 2.4 kg P/ha was lost from pastured catchments in 1 year in overland and interflow, with approximately half of this P being in dissolved form.

Location

Flaxley Agricultural Centre, Mount Lofty Ranges, South Australia

Related studies

NA

Key references and sources of this data synthesis

These data summaries have been extracted from

      i.        Fleming NK, Cox JW. 1998. Chemical losses off dairy catchments located on a texture-contrast soil: carbon, phosphorus, sulphur, and other chemicals. Australian Journal of Soil Research 36: 979 – 95.