Getting the most from nitrogen application is a key aim in the AHDB-led potato trials at Bruce Farms, Meigle, Perthshire. They have shown that there is an optimum level of nitrogen application, which might mean omitting the top dressing of 32kg of N/ha.

Potato farmers heard about this and more at the final Strategic Potato (SPot) Farm Programme open day this week at Strathisla Farms, near Blairgowrie.

“We have found that putting too much nitrogen onto a crop can reduce yield, so we are trying to work out the perfect amount to optimise output,” said Marc Allisson of plant research organisation NIABCUF. “We have reduced nitrogen by 32kg/ha and increased yield.”

What we will take away from the project is not having to bed till as much as we used to

This could save £30/ha for the grower.

“What we will take away from the project is not having to bed till as much as we used to. And we will only be stone-separating down to 10in as opposed to 12in, which saves a lot on fuel and machinery,” said Kerr Howatson, farm manager at Bruce Farms.

The trials have highlighted the importance of organic matter in the soil, at around 7%-8%, if the crop is to have less nitrogen applied.

Sometimes you think you are applying 24mm of water, but on a hot, sunny day it can be less than you think when it reaches the soil

Ally Allan from Agri-tech Services explained to attendees the benefits of using probes to assess moisture content in the soil in real time. Through a better understanding of the moisture available to the potato plant, growers have the ability to fine-tune irrigation.

“Sometimes you think you are applying 24mm of water, but on a hot, sunny day it can be less than you think when it reaches the soil,” said Kerr.

Attendees also heard about Hutton Institute’s live monitoring of potato blight as the season progresses; as opposed to the previous plan of testing plants at the end of the season.

We’ve had around 20 blight outbreaks so far this year

Farmers are asked to take samples from their blight crop and send it to the lab for analysis, which takes two to three days. Through genotyping, the specific strain can be identified – which is critical, as some are resistant to popular pesticides such as fluazinam.

David Cook from the Hutton Institute said: “We’ve had around 20 blight outbreaks so far this year, with two linages coming into the country. It’s important to keep testing up, as it allows the grower to know the best chemicals to use to reduce the impact. Luckily, we have 13 different active ingredients which can be used.”

AHDB is looking for the next SPoT trial farm and any farmer interested should contact Chris Leslie at the Edinburgh office.