Static potato yields prompt research

 While producers of wheat, milk and other products have seen yields increase by 40% or more, yields for potatoes have remained relatively constant, at around 100 tonne per hectare.

In an attempt to understand reasons behind the lack of increase in tuber yields, potato growers are undertaking a $240,000 research project with Plant and Food to investigate the role soil fertility has played in the current situation.

The yield gap analysis is being co-funded by Potatoes New Zealand, McCain Foods, Ravensdown and Plant & Food Research.
"For some years, the yields for potatoes have not been where you would expect when compared with for example carrots or wheat," says Mike Manning, general manager R&D for Ravensdown.

"Progress has been made in the area of plant genetics and other aspects of production in most areas of agriculture but we've not seen the same positive results in potato production," he says.

"We have a proactive group of farmers in Canterbury who want to learn as much as they can about options to improve growing practice. The implications here would be of interest throughout the country, so we decided to pool our resources."
Nutrient supply and fertiliser practice will be studied as well the incidence of pest and disease and other issues such as seed quality, irrigation management and soil physical conditions.

The fertiliser trial areas consist of large replicated treatment plots, eight rows by 10m, established within existing potato crops.
Growers have applied their usual levels of nitrogen, phosphorous, potassium and calcium – while the research team has varied the amounts of these nutrients on other plots to compare results.

Manning says the project has been a major undertaking, with all parties keen to ensure that sufficient funding and technical resources are available.

The next stage of the research, which could develop into a multi-year project, will be to analyse and review this season's results and then further consult with growers to determine which results require further research and investigation.