Information
Southeast Queensland Grazing Systems – Mt Mort
Information for this document was taken from Hydstra Brief project code SEQGM.
Level 1 General description
Purpose:
A native pasture community in Southeast Qld was monitored to determine the effects of management on runoff and soil loss.
Methods (brief)
Small plots were instrumented in Southeast Queensland at “Old Hidden Vale”, Mt Mort, 27 km SSE of Gatton. Hydrology and soil movement processes were examined under three management conditions at the small plot scale (30m2). Management conditions (treatments) were bare, grazed (paddock conditions) and exclosure (ungrazed).
Rainfall simulator study was also conducted in January 1994.
Key findings (brief)
- Runoff and soil loss increased with lower cover.
- With <5% cover, the coarse textured deep duplex soils lost 20% of rain as runoff compared with 50-60% on fine textured shallow duplex soils.
- Soil loss on the ‘bare’ coarse textured soil was 2.5 times greater than that measured on fine textured duplex soils.
Table 1. Mean annual (1993-1999) runoff, erosion and water quality for Mt Mort grazing trial. Predicted values adapted from HowLeaky Assessment (Freebairn & Cutajar, 2012)
|
Management Practice |
Slope length m |
Slope % |
LS1 |
Runoff mm |
Soil loss t/ha |
EMC 1 gm/L |
Normalised2 Soil loss t/ha |
Normalised3 EMC gm/L |
Predicted Runoff mm |
Predicted Soil loss t/ha |
|
Bare |
10 |
12 |
1.0 |
136 |
46 |
33.8 |
46 |
33.8 |
142 |
53.8 |
|
Grazed |
10 |
12 |
1.0 |
22 |
0.5 |
2.3 |
0.5 |
2.3 |
20.4 |
0.7 |
|
Exclosed |
10 |
12 |
1.0 |
3 |
0.06 |
2 |
0.06 |
2 |
16.8 |
0.23 |
1 Soil loss divided by runoff, primary sediment source, no allowance for deposition.
2 USLE factor used to correct normalised data to an LS =1
3 EMC normalised to an LS =1
Location
Mt Mort is located within the Bremer River catchment, approximately 7 km south of Grandchester in the valley of Franklin Vale Creek.
Related studies
N/A.