The complex balance of variables which contribute to the perfect potato are being put to the test at an East Anglian proving ground for the latest growing ideas.

%image(14827039, type="article-full", alt="AHDB "SPot East" farm demonstration at Elveden Estate. Pictured: Dr Mark Stalham from NIAB CUF talks to growers in a potato field.")

The Elveden Estate, on the Norfolk-Suffolk border near Thetford, is the nation's second Strategic Potato (SPot) Farm – a project co-ordinated by the Agriculture and Horticulture Development Board's potatoes division (AHDB Potatoes).

At its first open event this week, farmers were shown the initial phases of trials which will compare a diverse range of factors across a raft of commercial potato varieties.

They include the optimum timing of irrigation to control common scab, the efficiency of herbicides and nitrate fertilisers in different conditions, and the varying levels of susceptibility to infection, pests and drought.

But on Breckland's free-draining sandy soils, the key resource is water – with any small reduction in the irrigation requirement having the potential to have a massive impact on financial cost and environmental impact when multiplied across the estate's 10,000 acres of farmland.

Soil probes are used to assess the depth of moisture, while trials are under way to assess the impact of over-watering and find situations where less irrigation might be needed.

Dr Phil Burgess, head of knowledge exchange at AHDB Potatoes, said: 'There is a lot of research out there and a lot of science, but there seems to be a blockage in getting some of that practice onto farms.

'I think sometimes that blockage is because growers don't have the confidence to make a change. If you are growing one of these varieties and you have always applied a certain amount of water, and then someone comes along and says you can do it with a lot less than that – it sounds like a dangerous thing to do unless you have the confidence that it will work.

'This is all about giving growers that confidence. Over an enormous estate like Elveden, if you could save half an inch of water, it has a huge implication on the water resources that are available.'

One of the trials at Elveden explores the optimal use of water to control common scab, an infection which devalues potato crops, particularly where skin appearance is important.

Dr Mark Stalham, from NIAB CUF (Cambridge University Farm), said: 'The belief is that as soon as tubers form it is immediately susceptible to invasion from the organism which causes common scab. But you don't find that organism in the tuber in the first two weeks of its life.

'So we thought we could be a bit smarter, and time the irrigation for when the pathogens develop. The crucial period for irrigation is between week one and week three after tuber initiation.'

Andrew Francis, senior farms manager at Elveden, said the trials were increasingly important amid rising regulatory pressure on the use of resources such as water and chemicals.

He said: 'If you look at the herbicide trial, with the issues of product withdrawals and products being reviewed at EU Council level, we're probably going to be losing products we shouldn't be, so it is about learning to adapt to different products and newer products.

'The scab trial is all about optimising water use and trying to understand where the fail point is. Water timing is critical to within a 24-hour period for our soils and our varieties, and with a lot of pressure in the catchment to reduce water, we need to demonstrate how tolerant different varieties are, and where we reach that drop-off point.

'You don't often see potato trial sites on these light Breckland soils. One of the drivers for us being a SPot farm host, and the AHDB looking to the east, is that such a large proportion of potatoes are grown on relatively light soils, so we need to bring these theories here to test them and see if there are any tweaks to adapt them into best practice.'

Expert analysis on the trials at Elveden will be explained to growers at the SPot Farm (East) Open Day on July 5 at Avenue Farm, Icklingham. To register, click here.