To improve the adoption of liming practices in the medium to high rainfall zone of Western Australia by demonstrating the economic and environmental benefits of lime application and incorporation.
RESEARCH QUESTION
Can incorporation of lime economically remediate a subsoil acidity constraint on gravel soils?
RESEARCH OBJECTIVES
BACKGROUND SUMMARY
Forest gravel soils are common in the medium to high rainfall zone of Southern Western Australia and are estimated to account for about 2.4 million hectares of the state's farming area. Non-wetting and soil acidity issues are known to constrain the productivity of these soil types, which are common throughout the Southern DIRT region. Considering this, limited local research has been conducted in regards to the effects of incorporating lime as a method to alleviate these soil constraints more effectively and economically than the traditional method of top-dressing.
The trial was collaboratively designed by Southern DIRT R&D committee members and staff, Wes Lefroy of Precision SoilTech, and the landholders, Roger and Simon House. The focus of the treatments was to;
a) Utilise the most economic source of lime for the landowners,
b) apply the lime at a range of rates representative of both local practice and industry endorsed practice, and
c) incorporate the lime with equipment which are known to improve the movement of lime through the soil profile compared to top-dressing; while having minimal complicating factors (i.e. poor seed placement) which are commonly associated with other forms of deep tillage.
The trial is located 12 km north of Kojonup and was chosen for its combination of targeted soil type (forest gravel) and pH range (4.5 – 4.8 CaCl2) up to a depth of 60cm.
The methods for incorporating lime in the trial are offset discs and one way plough, with knife-points at seeding included as a control. Both offset discs and one way ploughs are generally used for the shallow incorporation of lime, and in this trial the depth achieved was approximately 10cm for the offset discs and 12cm for the one way plough. Research has shown that these incorporation methods can be more effective than the standard practice of top-dressing lime at increasing soil pH at depth by mixing lime into the soil profile when adequate rates are applied. While the lime is mixed well to the working depth of the implements, neither of these methods have the capacity to incorporate lime to depths beyond 20 cm.
Both offset discs and one way ploughs are considered by local growers as more cost-effective options for incorporating lime when compared to other methods (i.e. rotary spading). Annual plot soil testing and harvest yield will be the primary indicators used to assess how quickly and effectively the various treatments are able to raise pH at depth and increase production on forest gravel soils constrained by subsoil acidity.
Lead research organisation |
Southern DIRT |
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Host research organisation | N/A |
Trial funding source | GRDC LIE00008 |
Related program | N/A |
Acknowledgments |
Southern DIRT would like to thank Roger and Simon House of “Starhaven” for hosting, implementing and maintaining the trial; also for supplying the lime and investing significant time modifying the one way plough used in the trial, Wes Lefroy from Precision SoilTech for his assistance locating the site and designing the trial, Vivek Bhat for overseeing implementation of the trial as the Southern DIRT Project Officer at the time, and Southern DIRT members for their valuable input into determining the aims of the trial. This trial is supported by GRDC funding through LIE00008: Working together to deliver multiple benefit messages to growers through a whole systems approach to soil management. Soil acidity management strategies throughout Western Australia are available for download from: http://www.liebegroup.org.au/wp-content/uploads/2016/01/Soil-acidity-management-stratagi |
Other trial partners | Not specified |
Crop type | Cereal (Grain): Wheat |
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Treatment type(s) |
|
Trial type | Experimental |
Trial design | Randomised,Replicated |
Sow rate or Target density | 100 kg/ha |
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Sow date | 29 May 2015 |
Harvest date | Not specified |
Plot size | 11m x 30m |
Plot replication | 4 |
Paddock history | 2012 barley, 2013 fallow, 2014 quinoa |
Fertiliser |
29/05/2015: 100kg Allstar 04/07/2015: 50kg Urea 01/08/2015: 60kg Urea |
Herbicide |
22/05/2015: 1.5L Glyphosate, 16mL Nail 29/05/2015: 100kg Allstar & 4L/t Impact 21/07/2015: 750mL Tigrex
|
Insecticide |
22/05/2015: 100mL Dominex 21/07/2015: 100mL Dominex |
Fungicide |
18/09/2015: 145 mL/ha Folicur 430 SC |
Other trial notes |
FURTHER INFORMATION Southern DIRT P: (08) 9831 1074 W: southerndirt.com.au |
# | Variety |
Assessment (assessment) | Crop Stage (stage) |
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1 | █ 27/06/2015 | Establishment assess | 4 leaf - 1st tiller |
2 | █ 5/08/2015 | Establishment assess | Mid - late tillering |
3 | █ 20/08/2015 | Normalized Differenc | Late tillering - 2nd |
4 | █ 21/10/2015 | Shoot biomass | Mid - late flowering |
5 | █ 10/12/2015 | Harvest yield and gr | Maturity |
Rainfall trial total (mm) | 440.4mm |
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Rainfall trial gsr (mm) | 355.6mm |
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.