Information
Level 2 Detail of experimental conditions (Gunnedah)
Description of study
What?
Lang & McCaffrey (1984): Soil loss data is used to examine the relationship between soil loss and percentage ground cover.
Lang (1979): The relationship between surface runoff and ground cover was examined.
Hamilton (1970): A comparative study of the quantitative depressions in wheat yield and quality that result from sheet erosion was conducted at five Soil Conservation Research Stations over fourteen years (1955 – 1968). Data analysed for each Research Station was obtained over different time periods.
When and Where?
Lang & McCaffrey (1984): The study began in 1952 at the Gunnedah Soil Conservation Research Station. Average annual rainfall at the site is 640 mm, with 60% received in the warmer half of the year. Soil present on site is a duplex chocolate soil with a gravelly fine sandy clay loam overlying, at about 10cm depth, a light medium clay. The site has a 12% slope.
Lang (1979): The study commenced in 1952 and is situated on a uniform area of 12% slope. The soil is a duplex chocolate soil (Dr 4.12) with a gravelly, dark reddish brown A-horizon of fine sandy clay loam overlying, at about 10cm depth, a B-horizon of dark reddish brown light-medium clay. A clayey sand C-horizon is present below about 70cm.
The pasture composition varies with the grazing pressure. Bothriochloa decipiens and Stipa spp. are the principal components of the nil and lightly grazed plots, while various broad leaf species are dominant on the heavily grazed plots. Climate data is described in Table 1.
Hamilton (1970): The study was conducted at the Gunnedah Research Station from 1957 – 1960.
How?
Lang & McCaffrey (1984): Nine 0.01 hectare plots were grazed by sheep to simulate three treatments of nil, light, and heavy grazing rates. Each treatment was replicated three times.
Runoff was measured from the plots after each runoff producing rainfall event. Soil loss was estimated by taking duplicate samples of the runoff water, evaporating 50ml sub-samples in an oven at 105oC and weighing the evaporite. The percentage ground cover on each plot was estimated periodically throughout the year by either the point or area quadrat method.
Lang (1979): Nine 0.01 hectare plots were implemented with three treatments of nil, light and heavy grazed plots by sheep.
Runoff was collected in tanks and measured after each runoff-producing rainfall event. The percentage ground cover, average height and botanical composition of the cover on each plot were recorded periodically throughout the year.
Hamilton (1970): Two blocks were implemented on the site, one comprised of a wheat-fallow-wheat rotation and the other comprised of a fallow-wheat-fallow rotation. Three replicates of each treatment were randomized on each of the blocks. The treatments were as follows:
- Control – no soil removed
- Three inches of surface soil removed
- Six inches of surface soil removed
Each plot had a furrow dug along the entire length of the lower side to provide drainage and prevent run-off washing from plot to plot. Each plot had a harvested area of one hundredth of an acre or six rows of a combine for the required length.
Normal cultural practices were carried out throughout the experiment. Manual harvesting was completed and the seed was then threshed, cleaned and weighed. Samples were also tested for nitrogen determinations using the Kjeldahl method.
Project administration
Site identifier code: N/A
Principal investigator: Lang RD, McCaffrey LAH & Hamilton GJ
Principal data manager: N/A
Principal organizations: Scone Soil Conservation Service Research Centre, Cowra Research Centre, Soil Conservation Service of NSW
Data custodian: Scone Soil Conservation Service Research Centre
Key co-operators: Gunnedah Soil Conservation Research Centre
Data access policy: Research has been published but 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:
i. Lang RD & McCaffrey LAH. (1984). Ground cover – its affects on soil loss from grazed runoff plots, Gunnedah. Journal of Soil Conservation January 84: 56-61.
ii. Lang RD. (1979). The effect of ground cover on surface runoff from experimental plots.
- Hamilton GJ. (1970). The effect of sheet erosion on wheat yield and quality. Soil Conservation Journal. April pp. 118 – 123.
Keywords:
Soil loss, rainfall, ground cover, Sheet erosion, wheat yield, New South Wales wheat belt