Information
Level 2 Detail of experimental conditions (what might be found in a journal paper or project brief in Hydstra)
Description of study
What?
The site underwent 4 experiments; runoff and erosion plots, measurement of soil plant available water capacity (PAWC), pasture growth and water use and effects of cover and time of exposure on infiltration.
When and Where?
Monitoring for this project commenced in 1991 and ceased in 2000. The site is located within the black speargrass pasture unit that covers an area of 6.18M ha in south eastern Queensland. Soil at the site is a soloth formed from sandstone with a duplex profile. The surface soil has low water holding capacity (3 - 4 g/g) and is hardsetting. Slope is 10 – 15%.
Mean annual rainfall 7 km north of the site is 852 mm with a coefficient of variation of 27%. The majority of rainfall (70%) occurs between October and March. Vegetation throughout the site is open forest and consists mainly of narrow leaf ironbark and other eucalypts with an increase in density with increasing slope (Table 2).
How?
Three 3 m by 10 m long plots were installed to measure runoff, erosion and P losses under medium tree density. Treatments were bare, grazed (paddock conditions) and exclousre (ungrazed). Replicates of each treatment were prepared beside each runoff plot to be used for rainfall simulations.
Rainfall and Runoff
Rainfall and runoff from each plot were measured at 1 minute intervales using tipping buckets.
Erosion
Soil bedloads were measured from trapped sediments in modified Gerlach troughs, while suspended sediments were sampled from the outlet of the tipping buckets using a passive flow-proportional splitter.
Moisture Content
Neutron access tubes were installed in all plots and replicate areas to measure soil moisture contents, with additional tubes for destructive calibration and PAWC studies.
PAWC
Four neutron tube sites were wet using ponded water. Bulk density and drained upper limit moisture content profiles were measured using core samples and drainage was observed using the neutron probe. Moisture profiles after 7, 8, 24 and 48 hours drainage were similar, providing an estimate of drained upper limit. These data were compared with laboratory 0.33 and 15 bar moisture contents and wettest and driest profiles measured on the plots and used as PAWC parameters on water balance modelling.
Project administration
Site identifier code: N/A
Principal investigator: Silburn M.
Principal data manager: N/A
Principal organizations: Department of Natural Resources, Mines and Water
Data custodian: Department of Natural Resources, Mines and Water
Key co-operators: N/A
Data access policy: Research has not been published and base data is not archived
Planned pathway for data: completed study, no evidence of formal database records.
Data warehousing: for ongoing studies N/A
Planned data upload frequency: for ongoing studies N/A
Key references and sources of this data synthesis
These data summaries have been extracted from
- Mt Mort field visit notes February 1994, Management practices for productivity and sustainability of duplex soils under grazing. Mark Silburn January 1994.
- Hydstra project code SEQGM, Southeast Queensland Grazing Systems – Mt Mort. Silburn, M. 2000.
- Freebairn D & Cutajar J. 2012. Mt Mort HowLeaky Assessment.
Keywords:
south-east Queensland, sediment, slope, rainfall, ground cover.