Inter-row sowing into retained stubble in south west Victoria

Guideline for growers

  • SFS_FINAL_LogoInter-row sowing is strongly dependent on access to accurate and reliable auto-steer guidance systems.
  • Implement steer systems improve inter-row seeder tracking and avoids crabbing into old furrows.
  • Wider row spaces reduce crop competition with weeds but can reduce yield potential in cereals. Conversely wider rows improve pesticide contact and inter-row sowing.
  • Crop rotations play an important role in inter-row sowing establishment, weed, pest and disease control.
  • Some disc seeders have better trash handling capabilities compared to tyned seeders and are better suited to narrower row spaces.

Retention of large stubble loads in the high rainfall zone (HRZ) brings with it many and varied challenges. Crop establishment, seeder blockages, herbicide efficacy, integrated weed management, disease carry over, nutrition management, pest harbours and harvest management techniques are all a focus of the GRDC-funded project ‘Maintaining profitable farming systems in retained stubble (BWD00024)’.

SFS research

In 2014 at Yalla-Y-Poora, in the western districts near Geelong, SFS set up an on farm demonstration that compared a range of stubble management strategies. Trial plot seeding equipment, by design, is often unsuited to stubble retained research. SFS has therefore implemented on-farm trials using seeders and machinery specifically setup for inter-row sowing systems.

These included:

  1. Stubble retained, 30cm (high)
  2. Stubble retained, 15cm (low)
  3. Stubble burnt
  4. Stubble harvested high then incorporated
  5. Stubble harvested low into windrows and baled

The aim of the demonstration was to determine how stubble management influenced the establishment, yield and dry matter production of a canola crop sown with a tyned seeder, as well as slug numbers.

Observations:

  • Incorporated stubble caused serious seeder blockages, standing less so
  • Inter-row sowing into 30cm stubble had no negative impact on establishment
  • Canola sown into the burnt and 30cm retained standing stubble treatments displayed similar early vigour
  • Slug control was similar regardless of product used
  • Burt and incorporated strips were less affected by slugs in the untreated strips
  • Burnt stubble treatments yielded slightly more than other treatments

From the demonstration work there are some clear messages.

Inter-row sowing with tyned seeders is possible into 30cm retained stubble with RTK guidance, but agronomic management may need be adjusted to suit this system. A Gason seeder used was on 250mm row spaces which is considered the minimum row space.

Slug control products used had no impact on slugs but slug damage occurred in the retained stubble and baled strips.

Early vigour did not vary significantly between burnt or retained 30cm standing stubble treatments.

Final yields for retained 30cm standing stubble were lower than the stubble harvested at 30cm and burnt (Table 1). Reasons for this were unclear.

Table 1. Yield results SFS stubble management demonstration Yalla Y Poora 2014.

 

Yield (t/ha)

Stubble harvested at full height and burnt

2.396

Stubble harvested at full height and then incorporated ‘top downed’ and then sown

2.162

Stubble harvested low and spread

2.314

Stubble harvested low and baled

2.331

Stubble harvested at full height, then direct drilled into standing stubble

2.164

Stubble harvested at full height and burnt

2.443

Growers should gain some confidence when adopting a retained stubble system from this demonstration. Growers are reluctant to burn stubble for a range of reasons such as time taken, resources required, annual increases in restrictions, loss of ground cover, nutrients loss, erosion risks and air pollution.

The tyne and press wheel system is considered the least suited to inter-row seeding in tall stubble on row spaces greater than 25cm. Adoption of inter-row sowing is practically achievable in the HRZ and practicing growers and advisors are improving the system continually to maintain profitability at the same level as traditional burn practices.

SFS Barrs demo incorporate v standing stubble

SFS stubble management demonstration. Sowing into the tall retained v. tall incorporated treatment.

Challenges

While stubble retention provides recognised benefits there are also many problems related to retaining stubble and inter-row seeding, especially in the HRZ.

Inter-row sowing enables machinery to avoid stubble for ease of sowing and herbicide application but managing high stubble loads of 4-5t/ha or more can be difficult. Carryover stubble from the previous year can also add to the amount of stubble to be sown through. Careful management (cutting height) of stubble post-harvest is key to effective inter-row sowing in the upcoming year.

Growers have been adjusting their systems to eliminate or minimise problems as they arise. A number of growers have been retaining stubble and inter-row sowing for many years and have experienced and overcome many of the major problems.

To help avoid blockages and poor plant establishment, accurate RTK guidance (+-2cm) and autosteer is important and implement guidance in some cases to reduce crabbing. Sowing in the same direction on the same row spacing is also essential.

Disc seeders have increased trash handling capacity that improves inter-row sowing capabilities. They are more suited to narrower row spaces which have been shown to be an advantage in crops yielding higher than 3t/ha (Scott, Martin & Reithmuller et al). Disc seeders also have traits that require unique agronomic management to maintain crop yields at profitability levels the same as traditional systems.

Mixed farming with integrated livestock and cropping can be beneficial or problematic for an inter-row sowing system. Livestock can reduce the chaff portion of stubble on the ground by increasing rates of break down. If the stubble is higher in nutrition value (eg. frosted crops) sheep will eat it readily and reduce the total biomass. If it is not nutritious (eg. high yielding crops) they will consume very little and their traffic will only lay stubble over and increase problems with inter-row seeding.

As in any system changes to one area will impact on others and solutions must be based on a systems approach.

Thanks go to Greg & Kirrily Condon, Michael Sinclair, Steve Day and Matt Dart for their contributions.

JD Single disc unit

JD Single disc unit

References and links

stubble guideline interrow sowing SFS

GRDC stubble management guideline No. 11 – Inter-row sowing and stubble retention in a high rainfall zone

Greg & Kirrily Condon, GrassRoots Agronomy
Disc seeding in Southern NSW, Experience and observations a few years down the track
www.grassrootsag.com.au/assets/disc-lr.pdf
 E:  kirrily@grassrootsag.com.au

Barry Haskins
Using pre-emergent herbicides in conservation farming systems
http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0003/431247/Using-pre-emergent-herbicides-in-conservation-farming-systems.pdf
E: barry@aggrowagronomy.com.au

Dr Sam Kleeman
Seeding systems & pre-emergent herbicides
https://www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2015/02/Seeding-systems-and-pre-emergence-herbicides
E: samuel.kleemann@adelaide.edu.au

Scott BJ, Martin P and Reithmuller GP, 2013,
Row spacing of winter crops in broad scale agriculture
http://www.csu.edu.au/research/grahamcentre/publications/monograph/row-spacing-monograph

Ground cover TV, SFS seeder trial 
www.youtube.com/watch?v=rUeXhFp7aWs

SFS Meridian Ag seeder trial video interviews
www.youtube.com/watch?v=ffjj45dwjUU
www.youtube.com/watch?v=K3MecWUc2ek
www.youtube.com/watch?v=asBWmBfpbtU

 By Paul Breust
Research and trials Manager
Southern Farming System
E:  pbreust@sfs.org.au

GRDCLogoStacked_TM_CMYK

This research is being conducted by SFS as part of the GRDC Maintaining profitable farming systems with retained stubble initiative (project BWD00024 ‘Maintaining profitable farming systems with retained stubble in Victoria and Tasmania’).

Disclaimer: Any recommendations, suggestions or opinions contained in this publication do not necessarily represent the policy or views of Southern Farming Systems (SFS) or the Grains Research and Development Corporation (GRDC). No person should act on the basis of the contents of this publication without first obtaining specific, independent professional advice. SFS and GRDC and contributors to these guidelines may identify products by proprietary or trade names to help readers identify particular types of products. We do not endorse or recommend the products of any manufacturer referred to. Other products may perform as well as or better than those specifically referred to. SFS and GRDC will not be liable for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the information in this publication.
Stubble project overview: This guideline has been developed by SFS Farming Systems Group as part of the Maintaining Profitable Farming Systems with Retained Stubble initiative, funded by the Grains Research and Development Corporation (GRDC). The initiative involves farming systems groups in Victoria, South Australia, southern and central New South Wales and Tasmania collaborating with research organisation’s and agribusiness to explore and address issues for growers that impact the profitability of cropping systems with stubble, including pests, diseases, weeds, nutrition and the physical aspects of sowing and establishing crops in heavy residues.
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