Trial sites take the biscuit
A mixed picture has emerged of grain yields for autumn sown crops grown for research at Canterbury trial sites by the Foundation for Arable Research (FAR).
Autumn sown feed wheat yields of 10.5 tonnes a hectare this season are off the pace of the four-year average of 11.1t/ha.
However, some trial sites have performed better with feed and biscuit wheat yields above the long- term average at a dryland Chertsey site and at a dryland St Andrews site.
Research manager Rob Craigie said disease pressure appeared to have influenced yields for autumn- sown grain crops, but this was not widespread among the six Canterbury trial sites.
"We are back, but it's kind of a mixed picture because some sites the yields have been good," Craigie said.
"At Methven the trial did 13t/ha which is higher than the average."
He said other growers might also have experienced more disease than normal.
Septoria fungus was more visible in crops this season, infecting plant leaves to reduce the canopy area and yields.
Craigie said increasing septoria was probably related to warm conditions from the end of winter to early spring and had "taken the top" off some yields.
He said the fungus started to infect crops over winter and spread during wet conditions over spring, leaving autumn sown crops especially vulnerable.
"It's a disease we are seeing more of the last two to three seasons and seems to be building up. Prior to that we probably had 10 years with relatively low levels of the disease."
Heavier soils generating more crop canopy can build up septoria as the canopy created more humidity, but it could still be found on lighter soils with less canopy.
Fungicides are becoming less effective as the fungus is mutating and some newer strains are less sensitive to spraying regimes.
Craigie said more research was being carried out to work out which fungicide rates were most effective and to analyse new fungicides.
Further contributing to lower yields were increasing numbers of cereal aphids and wingless aphids because of warm weather. The aphids transmit the barley yellow dwarf virus, turning leaves a reddish colour and reducing yields.
Milling wheats are less affected particularly from aphids than feed, cereal and biscuit wheats because they are planted later.
The best feed wheat performers were Torch at a 11.3t/ha average over the six sites followed by Wakanui and the unnamed KWW46 variety. Torch showed good resistance against septoria and leaf rust and did well at 10.6t/ha at the irrigated Temuka site where there was high septoria levels and falling wheat - lodging - from wind. Wakanui and KWW46 excelled at the irrigated Methven site at 13.9t/ha and 13.8t/ha.
The Empress biscuit wheat variety averaged 10.6t/ha across the six sites closely followed by Claire at 10.5t/ha.
Researchers remain uncertain why the Methven site average of 13t/ha topped the four year 11.8t/ha average.
Autumn sown milling wheat averaged 8.7t/ha which was below the 9.4t/ha average over the last four years. New variety Discovery was the best milling wheat performer at 9.6t/ha but did better at irrigated sites than a dryland Methven site.
The barley cultivars of Sanette and SYN411-285 topped average yields at the Rakaia and St Andrews sites.
Craigie said there appeared to be reasonable yields for spring- sown crops but they had yet to be analysed and the overall season had been challenging.