CANOLA YIELD DECLINE

In a GRDC funded scoping study conducted in 2003 in southern NSW, canola yield decline was the number one research issue identified by growers. Whilst a range of factors have been identified as possible contributors to this decline, disease (particularly blackleg and sclerotinia) was seen as the most immediate issue requiring further research. However, intensive paddock surveys have also revealed that subsoil constraints, such as sodicity and salinity, could also be impacting on canola performance in some areas.

FarmLink has been involved in a number of collaborative projects investigating canola yield decline in southern NSW since 2003. These projects include:

Canola Plus (disease management) - 2003 to 2005

Canola Survey & Modelling - 2003 to 2005

Canola in Depth (impact of subsoil constraints) - 2007 to 2009

SUBSOILS

In a GRDC funded scoping study conducted in southern NSW in 2003, subsoil constraints was highlighted by growers as a priority topic requiring further research. Consequently, FarmLink has been successful in seeking funding for a number of subsoil related projects, including:

 Zone Management of Subsoils - 2004 to 2005

A one year, National Landcare Program funded project to evaluate the role of precision agriculture in identifying and addressing within paddock variability due to subsoils.

Yield maps and electro-magnetic surveys were used to identify variable zones within paddocks at five sites including Barmedman, Morangarell, Marrar, and Lockhart (x 2). These zones were ground-truthed through extensive sub-soil sampling to determine reasons for variable yields.

Lime, gypsum and deep ripping treatments were applied to each zone depending on results of the ground-truthing. Yield maps were used to determine treatment responses.

Subsoil Testing - 2005 to 2006

A one year, National Landcare Program funded project to raise awareness of subsoil issues and determine their extent and severity in the FarmLink region. 139 paddocks were soil sampled to at least 80cm depth, with depth intervals analysed for pH, chloride, electrical conductivity, exchangeable sodium, etc. Zonal maps of each of the major subsoil constraints identified in the region can be found in the brochure 'Subsoils in the FarmLink region' (click on hyperlink). 

What Lies Beneath (compaction on red soils) - 2007 to 2008

A one year, National Landcare Program funded project to determine the impact of mechanical and stock compaction on red soils. Treatments in the two trial paddocks at Greenethorpe and Yerong Creek included +/- deep ripping pre-sowing and +/- summer grazing. Both paddocks were sown using 2cm GPS technology (auto-steer). Extensive soil and root measurements were undertaken by CSIRO, including soil strength (penetrometer), soil porosity, root depth and root density. Results can be found in the brochure 'Compaction on red soils in the FarmLink region' (click on hyperlink).

Canola in Depth (impact of subsoils on canola yield decline) - 2007 to 2009

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