Regional specific agronomy has been identified as a need by growers in RCSN Open Local Forums, in particular in using regional specific agronomy demonstrations to assist decision making of growers.

The aim of this project was to use best district practice to examine if newer varieties respond differently to increasing nutritional inputs and whether this can be exploited by growers.

This was done by measuring crop performance with different sowings times and nutrition regimes, representing different decision-making scenario's depending on budget and seasonal rainfall.

This information should then assist grower’s decisions with variety specific agronomic management.

Wheat, barley and canola were tested in 2018, and wheat and barley in 2019, representing a range of quality segregations. Trials were located close to Hyden, Kojonup, Jerramungup, South Stirling, Mt Madden, Munglinup, Gibson and Scadden and Salmon Gums.

The 2018 season was characterised by significant autumn rainfall and below average seasonal rainfall for most sites. The first time of sowing was seeded dry for most cereal and canola trials and the second sowing followed opening rains.

There was little evidence from the eight locations in 2018 to support the idea that the latest varieties differ in their response to increasing N and P inputs in wheat, barley and canola such that it could be exploitable by growers. Some interactions between variety and N and P nutrition were identified but responses were isolated and varied with crop and site. For example, significant interactions were measured for wheat yield at Gibson and protein percent at South Stirling; barley yield at Jerramungup, protein at Hyden, protein at South Stirling and screenings at Kojonup; canolayield at Gibson and oil content at Hyden.

In 2019 the Western Australian wheatbelt experienced a late start to the winter growing season and one of its driest. Data from the Bureau of Meteorology show all sites tested in 2019 experienced a Decile 1 season with well below average seasonal rainfall.

The 8 locations for wheat and barley in 2019 tested N rate and timing and supported the findings of 2018 with very little evidence to support the idea that varieties differed in their response to increasing N inputs. In fact, the opposite was true with the four varieties of wheat and barley tested responding in very similar ways for yield and grain quality.

The lack of consistent variety x fertiliser interactions in these environments suggests growers need only consider a crop and not specific varieties in their agronomic management.

N and P nutrition in 2018 and N nutrition in 2019 data supports current farmer practices of adequate basal nutrient upfront for the season, followed by post-emergent nitrogen as season and yield potential warrant.

Conclusions of this study are limited by the site-specific growing conditions and choice of varieties.