Information
Level 2 Detail of experimental conditions (what might be found in a journal paper or project brief in Hydstra)
Description of study
What?
Orr et al. (2001): Yield and pasture composition were monitored at the pasture community scale on a grazing property at Calliope
Sallaway & Waters (1994): This study determined soil surface hydrological characteristic under varying stocking rates and pasture compositions. This was in order to investigate the effect of runoff and soil movement, influenced by grazing pressure, on grazing land with black speargrass (Heteropogon contortus).
When and Where?
Orr et al. (2001): The study commenced in 1988 at Calliope, Queensland. Mean annual rainfall at Calliope is 864 mm with 70% occurring between October and March. Maximum average temperature in summer is 30.5oC and minimum average temperature in winter is 12oC. Dominant soils on the site are a duplex (Dy3) and grey clay (Ug5), both of low fertility.
Sallaway & Waters (1994): A study was carried out on an existing grazing experiment at Calliope (Galloway Plains), west of Gladstone. The study site was on a commercial grazing property with over 80 years of grazing history.
Soil type is a Solodized solenetz, yellow duplex dy3, mottled grey to brown sodic texture contrast overlying freshly weathered tonalite (0.7 m to 1.0 m depth). The treatments consisted of three stocking rates (0.0, 0.25 and 0.5 steers/ha), which began in September 1988 with two pasture types (perennial grasses dominated by H. Contortu and bothriochloa bladhii and annual grass). Silver-leaved ironbark was the dominant understorey.
How?
Orr et al. (2001): The experiment was a randomised complete block design comprising 11 treatments and 2 replicates, 1 replicate on each of the 2 predominant soil types. The 11 treatments consisted of 3 pasture types by 3 stocking rates and 2 additional treatments. The 3 pasture types were native pasture, native pasture over-sown with introduced legumes and native pasture where a dry season supplement was offered. The 3 stocking rates were 0.25, 0.375 and 0.5 steers/ha (1 steer per 4, 3 and 2 ha, respectively). The 2 additional treatments were native pasture grazed at 0.125 and 0.187 steers/ha (1 steer per 8 and 5.3 ha, respectively).
The yield and botanical composition of all treatments were measured every 6 months in autumn and again in spring between 1989 and 1996. At each sampling, 6 trained operators assessed a total of 150 quadrats, each 0.5 m by 0.5 m, in each paddock for yield, botanical composition and species frequency using Botanal.
The density of H. contortus was monitored in 25 permanent quadrats, each 0.5 m by 0.5 m, located in native pasture grazed at 1 steer per 5, 4, 3 and 2 ha, legume over-sown and native pasture plus supplements / burning both grazed at 1 steer per 4 and 3 ha.
Sallaway & Waters (1994): Small runoff measuring plots were installed ranging between 80 – 120 m long and 60-80 m2 at each site. Plots were rectilinear with a slope of 6%. Larger plots were 20 m wide, covered 0.4 ha and bounded to contain surface runoff.
Landscape plots were installed within each of the three stocking rates and ran from the top of the slope to the toe of the slope.
Paired plots (10 m wide, 7- 9 m deep) were established for each of the stocking rates in the narrow-leaved land class and silver-leaved ironbark. These plots covered an area of speargrass and Aristida patch and represented the smallest hydrological unit that was recognised in the field.
A 4 L tipping bucket measured runoff from the small plots at 1 minute intervals. A 150 mm Parshall flume measured runoff from the larger plot. A capacitance water height measuring device was used to record depth of flow in the flume every 2 minutes. Rainfall was measured every minute by replicated tipping bucket rain gauges.
A rotating disc rainfall simulator was used to determine runoff and infiltration parameters. Parameters for a modified Green and Ampt infiltration model was derived. Rain was applied to a one square meter plot at an intensity of 56 mm hr-1 until a steady rate of runoff occurred (approx 20 min). Plots were replicated three times on each of the patch types for each of the land classes on each stocking rate.
A disc parameter applied at tensions of -1 and -3 of water, to allow separation of the 3.0 mm and 1.0 mm pores, was used to determine poor size. The measurements were regenerated five times. Pore size measurements were taken on each patch type for each of the land classes at each of the stocking rates.
Project administration
Site identifier code: na
Principal investigator: MM Sallaway & DM Orr
Principal data manager: -na
Principal organizations: Meat and Livestock Australia, Qld Beef Industry Institute, Department of Primary Industries (DPI)
Data custodian: DPI & Qld Beef Industry Institute
Key co-operators: Land and Water Resources Research and Development Corporation, Meat Research Corporation, Galloway Plains Pastoral Company
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 -na
Planned data upload frequency: for ongoing studies -na
These data summaries have been extracted from:
- Orr DM, Burrows WH, Hendricksen RE, Clem RL, Rutherford MT, Conway MJ, Myles DJ, Back PV, Paton CJ. 2001. Pasture yield and composition changes in a Central Queensland black speargrass (Heteropogon contortus) pasture in relation to grazing management options. Australian Journal of Experimental Agriculture41: 477- 485.
- Orr DM, Burrows WH, Hendricksen RE, Clem RL, Rutherford MT, Conway MJ, Myles DJ, Back PV, Paton CJ. 2001. Pasture yield and composition changes in a Central Queensland black speargrass (Heteropogon contortus) pasture in relation to grazing management options. Australian Journal of Experimental Agriculture 41: 477- 485.
Keywords:
Pasture, yield, grazing, speargrass