Information

A study of soil erosion on Vertosols of the eastern darling downs, Queensland (Greenwood).

Level 1 General description

Purpose:

This trial was established to examine 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.

Methods (brief)

This project 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.

Key findings (brief)

Surface cover was effective in reducing soil movement and runoff from contour bay catchments. 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.

Table 1. Mean annual runoff, erosion and water quality exploring the impact of slope (5%) and slope length (35m) at Greenwood (Freebairn and Cutajar 2012)

Description of Management system

LS1

Observed

(1980/81-1984/5)

EMC 1

(gm/L)

Normalised2 Soil loss

(t/ha)

Normalised3 EMC

(gm/L)

Simulated

(1980/81-1984/5)

Simulated

(1900-1999)

Runoff

(mm)

Soil erosion

(t/ha)

Runoff

(mm)

Soil erosion

(t/ha)

Runoff

(mm)

Soil erosion

(t/ha)

Stubble burnt

0.6

86

38

44.2

63.3

73.6

83

36

49

19

Stubble incorporation

0.6

69

10

14.5

13.7

24.2

71

12

35

5

Stubble mulch

0.6

60

5

8.3

8.3

13.9

60

6

31

2

Zero tillage

0.6

56

3

5.4

5

8.9

66

3

29

1

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

Greenwood via Acland, 25 km north-west of Toowoomba.

Greenwood is Lat 27.329, Long 151.726

Related studies

Greenmount

Wallumbilla

 

Level 2, level 3, level 4 and level 5