Researcher(s) |
Nick Poole Darcy Warren |
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Year(s) | 2020 |
Contributor | Field Applied Research (FAR) Australia |
Trial location(s) |
Gnarwarre, VIC
|
To assess the value of pre and post GS30 defoliation in winter and spring germplasm grown in HRZ regions of different season lengths
Individual objectives specific to the trial were:
- Assess the dry matter offtake differences resulting from GS22, GS30 & GS32 defoliations and their effect on final harvest dry matter, grain yield and harvest index of spring versus winter wheat.
- Assess whether April sown spring wheat that has been “reset at GS32 (defoliated)” is higher yielding than GS30 and GS22 grazed and ungrazed crops.
- To assess whether the dry matter offtakes of longer season winter wheats at GS22 are more profitable (dry matter offtake and grain yield) than the same winter wheat defoliated at GS30
• All defoliation treatments reduced grain yield relative to the ungrazed crop except the “light graze” GS30 treatment in Trojan and the tillering defoliation (GS23) in RGT Accroc.
• Those defoliation treatments that removed larger amounts of dry matter at stem elongation (GS30-32) invariably reduced grain yield more.
• The concept of resetting Trojan at GS32 was unsuccessful in maintaining or increasing yield from a late April sow date. In addition, the undefoliated crop was not affected by frost.
• In Trojan both “light grazing” and “hard grazing” did not reduce yield with all treatments showing canopy compensation by flowering when assessed by canopy reflectance.
• With Trojan at 25 cents/kg dry matter and $300/t for grain the light grazing was the only treatment to produce a similar margin to the ungrazed control.
• In RGT Accroc where grazing was later than planned (and past the cut off of GS30) GS31 defoliation produced large dry matter offtakes and large reductions in grain yield but at the prices chosen would have been more profitable than the ungrazed control.
• The most profitable crop was the RGT Accroc defoliated at the end of tillering (GS29) which gave yields equal to the ungrazed and 3200 kg/ha dry matter removed.
Rotation position: 1st cereal following canola
Soil Type: Grey clay loam
Lead research organisation |
Field Applied Research (FAR) Australia |
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Host research organisation | N/A |
Trial funding source | GRDC FAR2004-002SAX |
Related program |
FAR Hyper Yielding Crops 2020-2022 |
Acknowledgments | N/A |
Other trial partners | Not specified |
Crop type | Cereal (Grain): Wheat |
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Treatment type(s) |
|
Trial type | Experimental |
Trial design | Randomised,Replicated,Blocked |
Sow rate or Target density | 180 seeds/m2 |
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Sow date | 25 April 2020 |
Harvest date | 31 December 2020 – 8 January 2021 |
Plot size | Not specified |
Plot replication | Not specified |
Fertiliser |
Sowing Fertiliser: 100kg/ha MAP Nitrogen: 23 June- 69 N kg/ha 7 August- 69 N kg/ha |
Fungicide |
GS31- Opus 500ml/ha GS39- Radial 840ml/ha |
Seed treatment | Vibrance & Gaucho |
Other trial notes |
The concept of “resetting” is specifically designed for early sowing spring wheat that develops too quickly from earlier sowing than would be recommended, in this case mid-April. The idea is that defoliation later than GS31 specifically removes advanced main stems that would have been frosted due to their very early development. Please note this is an experimental approach and should not yet be applied to commercial acreage. |
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.