Information
Level 2 Detail of experimental conditions (what might be found in a journal paper or project brief in Hydstra)
Description of study
What?
A medium-term (10 years) stubble x tillage field experiment was established in 1984 on a redbrown earth at Tarlee, 70 km north of Adelaide.
When and Where?
The study was established in 1984 in Tarlee, South Australia on a fine, mixed thermic Calcic Palexeralf soil with a slope of 4 – 6 %. The 0 – 5 cm soil layer has 16 % clay, 18 % silt, 65 % sand and a pH of 6.4. The climate in Tarlee is Mediterranean, with 450 mm rainfall/year, falling predominantly in the winter (June – August).
How?
The experimental design was a randomised split-split plot with two replicates of three levels of annual stubble retention (0.5, 3.0, 5.0 t/ha/year) as main plots; subplots of four land management treatments [no-tillage NT, direct-drill (DD), reduced tillage (RT), conventional cultivation (CC)]; and sub-subplots of four levels of N (0, 20, 40 and 80 kg N/ha).
The rotation was continuous cropping: 1984 – wheat; 1985 – wheat; 1986 – peas; 1987 – wheat; 1988 – barley; 1989 – peas; 1990 – wheat; 1991 – barley; 1992 – peas; 1993 – wheat.
Rainfall simulation studies were done on all main and subplot treatments. Sub-subplot treatments were 1-m2 split-plots (on plots of 40 kg N/ha only) comparing the effects of two surface conditions [bare soil, existing stubble or standard cover (100% cover, August and October only)] on rate and volume of runoff and soil and nutrient loss. Existing stubble cover during simulation depended on crop, time of year, tillage regime, and rotation.
A microprocessor-controlled rotating disc rainfall simulator was used to simulate rain and collect runoff from each subplot. Water was applied to each subplot at 100mm/hr for 18 minutes, giving a total rainfall of 30mm. A dual conveyor-belt was used to lift runoff material flowing off the target areas during the simulation. Runoff was measured after every 5 mm rainfall event using 2 L laboratory cylinders. Total runoff after every event was shaken vigorously in a bucket and subsamples of the runoff and sediments were taken in 100 mL plastic vials. The rates of soil, nutrient and surface water losses were determined in the laboratory. Water in the vials was evaporated at 35oC prior to undertaking analysis.
Project administration
Site identifier code: NA
Principal investigator: Malinda DK
Principal data manager: NA
Principal organizations: South Australian Research and Development Institute
Data custodian: South Australian Research and Development Institute
Key co-operators: NA
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
Key references and sources of this data synthesis
These data summaries have been extracted from:
i. Malinda DK. 1995. Factors in conservation farming that reduce erosion. Australian Journal of Experimental Agriculture 35: 969 – 78.
Keywords:
Nutrient loss, soil loss, erosion, conservation, farming practices