The Brigalow Catchment Study: I*. Overview of a 40-year study of the effects of land clearing in the brigalow bioregion of Australia
B. A. Cowie A C , C. M. Thornton B and B. J. Radford BA Queensland Department of Natural Resources and Water, PO Box 1762, Rockhampton, Qld 4700, Australia.
B Queensland Department of Natural Resources and Water, LMB 1, Biloela, Qld 4715, Australia.
C Corresponding author. Email: bruce.cowie@nrw.qld.gov.au
Australian Journal of Soil Research 45(7) 479-495 https://doi.org/10.1071/SR07063
Submitted: 21 May 2007 Accepted: 3 October 2007 Published: 12 November 2007
Abstract
This paper describes a long-term, paired-catchment study, its broad findings, and considerations for future resource management of brigalow lands in north-eastern Australia. The Brigalow Catchment Study (BCS) commenced in 1965 with a pre-clearing calibration phase of 17 years to define the hydrology of 3 adjoining catchments (12–17 ha). After 2 catchments were cleared in 1982, 3 land uses (brigalow forest Acacia harpophylla, cropping, and grazed pasture) were monitored for water balance, resource condition and productivity, providing information for scientific understanding and resource management of the major land uses of the brigalow bioregion.
In addition, this paper draws upon several project reviews to highlight the value of the BCS as an ‘outdoor laboratory’, its data resource, and to reflect on the study’s scientific rigor to support present and future value. An assessment of the BCS against national and international attributes of best practice for long-term studies showed the study to rate highly in aspects of design, implementation, monitoring, and data management, and moderately in formal publication, strategic management, and networking. The literature shows that Brigalow Catchment Study is the longest paired-catchment study in Australia, and continues to sample the interactions between climate, soils, water, land use, and management.
Finally, this paper provides the context for component-specific papers on changes in hydrology, productivity, and salt balance. Results from the study to date include: a doubling of runoff after clearing, a reduction in wheat yield by more than 60% over 20 years, a halving of pasture availability 3 years after clearing, a decline in cattle liveweight gain of 4 kg/ha.year over an 8-year period with a constant stocking rate, and the leaching of 60% of the root-zone (0–1.5 m) chloride after clearing for cropping. Unanticipated applications of the data from the study include: (i) a crucial set of soil samples for calibration of the RothC soil carbon model used to estimate Australia’s soil carbon emissions; and (ii) estimates of deep drainage as a basis for salinity risk assessment in the region.
Additional keywords: hydrology, erosion, long-term, runoff, land use, Acacia harpophylla.
Acknowledgments
Many staff have contributed to the design and execution of this study. We thank you H Pauli, J Rosser, A Webb, P Lawrence, R Bryant, A Dowling, H Hunter, N Cocaris, J Kalnins, R Scarborough, R Puschmann, R Gillespie, D Sinclair, B Kitchen, A Key, P Hansen, G Thomas, E Anderson, P Back, D Miles, W Burrows, M Nasser, A Lloyd, A Barnes, M Jeffery, T James, and staff of the NRW Chemistry Centre and the DPI&F Brigalow Research Station. The authors acknowledge input from Dr David Freebairn in his role as Strategic Science leader of the BCS in 2006/07. He was able to carry out this task as part of a Land and Water Australia Senior Research Fellowship.
Brown AE,
Zhang L,
McMahon TA,
Western AW, Vertessy RA
(2005) A review of paired catchment studies for determining changes in water yield resulting from alterations in vegetation. Journal of Hydrology 310, 28–61.
| Crossref | GoogleScholarGoogle Scholar |
[accessed 24/09/2007].
Connolly RD,
Freebairn DM, Bridge BJ
(1997) Change in infiltration characteristics associated with cultivation history of soils in south-eastern Queensland. Australian Journal of Soil Research 35, 1341–1358.
| Crossref | GoogleScholarGoogle Scholar |
[accessed 24/09/2007].
Dowling AJ,
Webb AA, Scanlan JC
(1986) Surface soil chemical and physical patterns in a brigalow-Dawson gum forest, central Queensland. Australian Journal of Ecology 11, 155–162.
| Crossref | GoogleScholarGoogle Scholar |
[accessed 24/09/2007].
Johnson RW
(2004) Vegetation survey of the Brigalow Research Station, Theodore, Queensland. Proceedings of the Royal Society of Queensland 111, 39–61.
[accessed 24/09/2007].
McCown RL,
Hammer GL,
Hargreaves JNG,
Holzworth DP, Freebairn DM
(1996) APSIM: a novel software system for model development, model testing and simulation in agricultural systems research. Agricultural Systems 50, 255–271.
| Crossref | GoogleScholarGoogle Scholar |
[accessed 24/09/2007].
Radford BJ,
Thorburn PJ, Key AJ
(1995) Enhancement of wheat establishment with modified sowing and fallow management techniques. Soil and Tillage Research 36, 73–89.
| Crossref | GoogleScholarGoogle Scholar |
[accessed 24/09/2007].
Yu B
(1998) Rainfall erosivity and its estimation for Australia’s tropics. Australian Journal of Soil Research 36, 143–165.
| Crossref | GoogleScholarGoogle Scholar |
*Parts II and III, Aust. J. Soil Res. 45(7), 496–511; 512–523.