TRIALS at Merredin have demonstrated that fertiliser decisions largely do not affect the performance of different wheat and barley varieties in the eastern Wheatbelt.
Yield and grain quality rankings for wheat and barley varieties grown using local management practices, especially for crop nutrition, were shown to be reasonably consistent with those achieved in adjacent Grains Research and Development Corporation (GRDC) National Variety Trials (NVT).
The Merredin and Districts Farm Improvement Group (MADFIG) administered the ‘yardstick’ trials over three years from 2015.
Identified as a priority by MADFIG and the Kwinana East GRDC Regional Cropping Solutions Network (RCSN) group, the project was designed to add value to NVT testing by using typical local grower nutrient management practices adjacent to the NVT site.
The program provides access to independent results on the performance of recently released grain and field crop varieties.
It is a national program of comparative crop variety testing with standardised trial management, data generation, collection and dissemination.
Merredin grower and MADFIG member Andrew Crook said the trials were initiated after a series of dry seasons highlighted the importance of getting variety choice right and raised questions about whether varieties differed in their responses to fertiliser management.
“During this period, some local growers questioned whether NVT results were fully applicable to them given the standard amount of fertiliser used in the NVT trials was higher than rates commonly used by growers in the area,” Mr Crook said.
“However, results from three years of the yardstick trials have shown that variety performance rankings, especially for wheat, are reasonably consistent with NVT variety rankings in the area.
“This should give local growers confidence that varieties that perform well within the NVT program should also perform well when grown under their own management systems.”
Mr Crook said the trials highlighted that seasonal variation had a greater impact on individual variety performance than nutrition strategies.
“This highlights the importance of understanding the key factors that will influence variety performance and how they will perform across seasons,” he said.
The trials, on medium-to-heavy textured soils, evaluated 10 wheat varieties and five barley varieties in 2015, 12 wheat varieties and five barley varieties in 2016, and 14 wheat varieties and six barley varieties in 2017.
Four nutrition strategies were implemented across the wheat and barley trials to represent various district fertiliser strategies reflective of common seasonal or budgetary scenarios.
Three of the treatments remained the same for the three seasons and a ‘play the season’ strategy differed depending on rainfall.
Fertiliser strategies included lower rates of phosphorus and generally lower rates of nitrogen than those used in the adjacent NVT trials.
“The results indicate that some fertiliser is equal to, or better than none, for all varieties tested across the seasons,” Mr Crook said.
“Recognising favourable seasons and responding with appropriate management is the challenge, as there is a greater opportunity cost from not maximising profit potential in a favourable season.
“Equally, the trial results show the importance of being conservative in a dry season.”
In 2018, the GRDC invested in several other similar yardstick trials, which are being locally managed and run in each of WA’s five grain-receival port zones.