Information
Level 2 Detail of experimental conditions (what might be found in a journal paper or project brief in Hydstra)
Description of study
What?
This study monitored runoff and sediment movement from irrigated furrows of different lengths and slope gradients, and the influence of rainfall and cultivation on a cotton farm within central Queensland
When and Where?
During the 1986-87 cotton growing season (September – March) a study was undertaken on a cotton farm within the Emerald Irrigation Area, Queensland. The farm is situated on black cracking clay; mollic torrert, fine montmorillonitic hyperthermic, 58% clay and pH 7.8.
The region has a semi-arid tropical environment. Rainfall predominantly occurs during the summer months with 66% of rainfall between November and March. During the study, September, October and January had greater rainfall than the corresponding long-term monthly averages.
How?
Six furrows were constructed for each of the furrow lengths. Short furrow lengths (SFL) were 241 m, and long furrow lengths were 482 m each with a 1% slope gradient. Furrows were formed 1 m apart and constructed at a width to suit the machinery used by the farmer.
Runoff from the furrows was discharged into a taildrain. Runoff from both treatments was calculated using a 150 mm Parshall flume and associated water-level sensor. Runofff from the taildrain was measured using a rectangular weir and water level sensor. Rainfall and flow height were recorded at 6 minute time intervals on a data logger. During all rainfall and runoff events, 1 litre water samples were taken by hand every 6 minutes at the outlet of the flume. Water sampling intervals were extended when irrigation flow rates were constant, or during the recession of a storm runoff. Sediment concentration was determined by oven-drying.
Six irrigation events were run on both of the furrow length treatments. An initial irrigation was performed to water the cotton beds before sowing when runoff was not measured. Irrigations were run until the full length of the site had been watered. Runoff duration was measured over a 3 hour period for both of the furrow length treatments.
The crop was sown on the 31 October. Three cultivations were performed during the crop to control weeds and reshape the cotton beds. The change in cross section of the six farrows due to cultivation, irrigation and rainfall was determined by placing a measuring staff across the top of the cotton beds then measuring the vertical distance to the soil at 5 cm intervals along the staff. Crop canopy cover was visually estimated in 1m2 areas along the furrow length.
Project administration
Site identifier code: N/A
Principal investigator: C. Carroll
Principal data manager: N/A
Principal organizations: Queensland Department of Primary Industries
Data custodian: Queensland Department of Primary Industries
Key co-operators: S. Denaro
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
Carroll C, Halpin M, Bell K, Mollison J. (1995). The Effect of Furrow Length on Rain and Irrigation-induced Erosion on a Vertosol in Australia. Australian Journal of Soil Research 33: 833-50
Keywords:
Emerald Irrigation Area, sediment, runoff, furrow, furrow length, soil loss, cotton