Project Details (2003 to 2005):

The purpose of this GRDC funded project, run from 2003 to 2005, was to ‘expand the focus’ on disease as the primary cause of canola yield decline. The project, involving CSIRO, agricultural consultants and FarmLink, involved detailed paddock surveys to detect the impact 'other factors' are having. The surveys were conducted by agronomic consultants across high and low rainfall areas in the north, central and south of the FarmLink region.

The information collected included soil, management and climate data, as well as crop growth stage observations, blackleg and sclerotinia assessments, root restriction assessments and micronutrient testing. Targeted soil and plant analyses were also undertaken to further investigate high levels of root restriction found in the southern region.

Modelling showed that most of the paddocks surveyed (75%) yielded to their potential based on seasonal conditions. However in the survey area south of Wagga, monitoring showed rooting depth and yields were being reduced by compaction, sodicity and high soil strength.

APSIM Canola Model

The survey data has been used to ‘road test’ the APSIM canola model through CSIRO. This model can be used to calculate potential yields for a given variety, sowing date, daily weather conditions, plant density, and available soil water and nitrogen. It predicts crop yields that are free from pests, weeds, diseases and nutrient deficiencies.

Model predictions have shown that canola crops in southern NSW yield to their potential when they are kept disease-free. It has also shown that sowing date can have a very strong influence on yield. In high rainfall situations or ‘soft’ finishes, the model shows a 3-4% yield loss each week sowing is delayed. In drier situations with a tighter finish, yield losses can be up to 6-8% per week.

As a result of this project, the APSIM canola model is now commercially available as a decision making tool through the Yield Prophet program (available through the Birchip Cropping Group). FarmLink has subscribed to run four canola paddocks in the region through Yield Prophet in 2007 to help growers make better management decisions. The yield forecast reports from these paddocks are updated monthly in FarmLink's 'Weather or Not' newsletter which is available to members.

Click here for outcomes of the Canola Survey & Modelling project

 More Links for Canola Yield Decline below:

'Canola Plus' (disease)

'Canola in Depth' (subsoil constraints)