Information
A study of soil erosion on a Vertosols of the Eastern Darling Downs, Queensland (Greenmount)
Level 1 General description
Purpose:
Freebairn and Wockner (1986) examined the influence of soil surface conditions on runoff and soil erosion, on a site representative of one of the major soil types of the eastern Darling Downs.
Titmarsh et al. (2009) determined the effect of land use and soil type on the nitrogen and phosphorous levels evident in runoff from catchments in the Queensland Murray Darling Basin.
Methods (brief)
Freebairn and Wockner (1986) examined the influence of rainfall intensity, runoff rate, and ground cover on suspended sediment moving through a flume at the exit from a contour bay and the effects of contour banks on sediment delivery to streams were evaluated. Several methods of sampling and calculating suspended soil loss were also evaluated.
Titmarsh et al. (2009) collected Nitrogen and Phosphorous levels in rainfall and runoff samples over three years for thirty-one small catchments (<10 ha in size), each with a particular land use and soil type combination and from three sets of larger nested catchments (3 - 200000 ha) with mixed land use/soils in the QMDB.
Key findings (brief)
Freebairn and Wockner (1986) found that runoff and sediment concentration were both inversely related to surface cover and total soil movement was greatly reduced by surface cover. Greater than 75% of the variance in soil movement from single events was explained by surface cover and peak runoff rate.
Titmarsh et al. (2009) found that export of N and P was positively correlated with soil fertility and increased as land use intensity increased.
Table 1. Mean runoff and soil loss measurements for the period 1978-90. Slope length was 60m and slope percentage was 7% (Freebairn and Cutajar, 2012)
|
Management system |
Measured |
Predicted |
||||||||
|
Runoff (mm) |
Hillslope erosion (t/ha) |
Suspended Sediment loss1 (t/ha) |
LS1 |
EMC 1
gm/L |
Normalised2 Soil loss t/ha |
Normalised3 EMC gm/L |
Runoff (mm) |
Hillslope erosion (t/ha) |
Suspended Sediment loss2 (t/ha) |
|
|
Stubble burnt (1978-89) |
68 |
45 |
4.6 |
1.2 |
6.8 |
3.8 |
5.6 |
66 |
42 |
9 |
|
Stubble incorporated (1976-89) |
47 |
13 |
1.4 |
1.2 |
3 |
1.2 |
2.5 |
46 |
14 |
4.3 |
|
Stubble mulch (1978 -89) |
47 |
9 |
0.8 |
1.2 |
1.7 |
0.7 |
1.4 |
47 |
10 |
2.9 |
|
Minimum tillage (1979-89) |
35 |
1 |
0.3 |
1.2 |
0.8 |
0.25 |
0.7 |
33 |
1.5 |
0.6 |
|
Perennial pasture (1987-90) |
32 |
1 |
0.2 |
1.2 |
0.6 |
0.2 |
0.5 |
35 |
1.1 |
0.4 |
1Soil 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
The “Marylands” property is located 1.3 km northeast of Greenmount.
Greenmount is Lat 27.329, Long 151.726
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