Herbicide efficacy in retained stubble systems

2016
CC BY 4.0

Research organisatons
Funding source

Trial details

Researcher(s) Amanda Cook (SARDI)
Ian Richter (SARDI)
Year(s) 2016
Contributor Eyre Peninsula Agricultural Research Foundation
Trial location(s) Minnipa Agricultural Centre, SA
Related trials
Herbicide efficacy in retained stubble systems locations
Aims

The GRDC project ‘Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula’ aims to improve farm profitability while retaining stubble in farming systems on upper Eyre Peninsula (EP). Weed control in stubble retained systems can be compromised when stubbles and organic residues intercept the herbicide and prevent it from reaching the desired target, or the herbicide is tightly bound to organic matter. Reduced herbicide efficacy in the presence of higher stubble loads is a particular issue for pre-emergence herbicides. Current farming practices have also changed weed dormancy in barley grass genotypes in many paddocks on Minnipa Agricultural Centre (MAC).

 

As a part of the stubble project this trial was undertaken to assess herbicide efficacy (effectiveness) in different stubble management systems. To understand how herbicides perform it is important to know the properties of the herbicide, the soil type and how the herbicide is broken down in the environment. The availability of a herbicide is an interaction between the solubility of a herbicide, how tightly it is bound to soil particles and organic matter, soil structure, cation exchange capacity and pH, herbicide volatility, soil water content and the rate of herbicide applied (EPFS Summary 2015, p132).

 

This article reports on the results of the second year of the trial, with a third year of the trial to be conducted in 2017.

Key messages
  • Herbicides which may be influenced by high stubble loads include trifluralin, triallate, pyroxasulfone, prosulfocarb and metalochor products. If grass weeds are an issue in paddocks with high stubble loads (greater than 50% stubble cover), removal of some stubble may maximize the herbicide activity and grass weed control.
  • In-crop germination patterns are later for barley grass than for other grass weeds in MAC paddocks, which is limiting early control with pre-emergence herbicides.
  • If you expect most of your grass weeds to emerge straight after sowing maybe 2 L/ha trifluralin (plus an added herbicide depending on cost and risk factors such as seasonal conditions, soil type, rotation etc.) is the best value for your system.
  • If you have a later germinating population, and aim to reduce the seed bank, you may be better investing in some of the more expensive herbicide mixes even though they may cost more in the first season.
Lead research organisation Eyre Peninsula Agricultural Research Foundation
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC EPF00001
Related program Maintaining profitable farming systems with retained stubble
Acknowledgments

Thanks to Ben Fleet, Andy Bates, Nigel Wilhelm and Rick Llewellyn for help with this trial and to Sue Budarick, Tegan Watts, Lauren Cook and Katrina Brands for their help collecting and processing samples. Trial funded by GRDC Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula (EPF00001).


Other trial partners Not specified
Download the trial report to view additional trial information

Method

Crop type Cereal (Grain): Wheat
Treatment type(s)
  • Herbicide: Rate
  • Herbicide: Type
  • Stubble: Management
Trial type Experimental
Trial design Replicated

Minnipa Agricultural Centre 2016

Sow rate or Target density 60kg/ha
Sowing machinery

The trial was sown at 3-4 cm depth with an Atom-Jet spread row seeding system with press wheels (plot seeder)

Sow date 30 May 2016
Harvest date 4 November 2016
Plot size 20m x 2m
Plot replication 3
Fertiliser

DAP @ 60 kg/ha

Herbicide

knockdown of 1.2 L/ha of Roundup Attack on 29 May

Herbicide treatment

Control Untreated

Trifluralin (1.5 L/ha)

Trifluralin (2 L/ha)

Trifluralin (1.5 L/ha) + Lexone (Metribuzin) 180 g (post)

Trifluralin (1.5 L/ha) + Diuron 900 (400 g/ha) (pre-emergent)

Trifluralin (1.5 L/ha) + Diuron 900 (high rate) (pre-emergent)

Trifluralin (1.5 L/ha) + Avadex (Tri-allate) (1.6 L/ha) (pre-emergent)

Trifluralin (1.5 L/ha) (pre) + Monza (sulfosulfuron) (25 g/ha) (post)

Monza (sulfosulfuron) 25 g (pre-emergent)

Sakura (118 g) (pre-emergent)

Monza (sulfosulfuron) (25 g) + Sakura (118 g) (pre-emergent)

Sakura (118 g)+ Avadex (Tri-allate) 3 L (pre-emergent)

Boxer Gold (2.5 L/ha) (pre-emergent)

Boxer Gold (2.5 L/ha) (post)

Sakura (118g)+ Avadex (Tri-allate) 3 L (pre-emergent) + Boxer Gold 2.5 L (post)

Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Treatment 1
Income less herbicide cost ($/ha) Yield (t/ha) Crop Establishment (plants/m2) Early dry matter (t/ha) Herbicide cost ($/ha) Late dry matter (t/ha)
1 Control Untreated 428 2.22 109 0.54 0 4.79
2 Trifluralin (1.5 L/ha) 421 2.23 92 0.35 9 4.8
3 Trifluralin (2 L/ha) 428 2.28 88 0.39 12 4.64
4 Trifluralin (1.5 L/ha) + Lexone (Metribuzin) 180 g (post) 421 2.26 107 0.44 15 4.71
5 Trifluralin (1.5 L/ha) + Diuron 900 (400 g/ha) (pre-emergent 413 2.21 102 0.45 14 4.61
6 Trifluralin (1.5 L/ha) + Diuron 900 (high rate) (pre-emergent) 421 2.28 91 0.36 19 4.22
7 Trifluralin (1.5 L/ha) + Avadex (Tri-allate) (1.6 L/ha) (pre-emergent) 392 2.16 76 0.26 25 4.3
8 Trifluralin (1.5 L/ha) (pre) + Monza (sulfosulfuron) (25 g/ha) (post) 397 2.24 95 0.44 35 4.83
9 Monza (sulfosulfuron) 25 g (pre-emergent) 393 2.17 101 0.37 26 4.43
10 Sakura (118 g) (pre-emergent) 387 2.21 96 0.33 40 4.21
11 Monza (sulfosulfuron) (25 g) + Sakura (118 g) (pre-emergent) 318 1.99 89 0.28 66 3.84
12 Sakura (118 g) + Avadex (Tri-allate) 3 L (pre-emergent) 355 2.2 97 0.36 70 4.03
13 Boxer Gold (2.5 L/ha) (pre-emergent) 405 2.29 97 0.45 37 4.82
14 Boxer Gold (2.5 L/ha) (post) 386 2.19 99 0.47 37 4.79
15 Sakura (118 g) + Avadex (Tri-allate) 3 L (pre-emergent) + Boxer Gold 2.5 L (post) 314 2.18 91 0.3 107 4.14

Crop Establishment plants/m2


Loading

Early dry matter t/ha


Loading

Herbicide cost $/ha


Loading

Income less herbicide cost $/ha


Loading

Late dry matter t/ha


Loading

Yield t/ha


Loading
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Minnipa Agricultural Centre, SA Red loam
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Minnipa Agricultural Centre, SA Calcarosol
Soil Moisture Source: BOM/ANU
Average amount of water stored in the soil profile during the year, estimated by the OzWALD model-data fusion system.
Year Minnipa Agricultural Centre SA
2016 409.0mm
2015 381.0mm
2014 439.7mm
2013 385.5mm
2012 407.7mm
2011 453.8mm
2010 454.3mm
2009 466.5mm
2008 380.6mm
2007 367.6mm
2006 384.7mm
2005 350.4mm
2004 343.8mm
2003 348.6mm
2002 343.5mm
2001 396.8mm
2000 422.6mm
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

Loading

Climate

Minnipa Agricultural Centre SA 2016


Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 241mm
Rainfall trial total (mm) 391mm
Rainfall trial gsr (mm) 268mm

Derived climate information

Minnipa Agricultural Centre SA

Loading
Loading
Loading

Some data on this site is sourced from the Bureau of Meteorology

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.

Trial report and links

2016 trial report



Trial last modified: 04-06-2019 13:30pm AEST