Europe, UK, Ireland

AHDB spot trials: SPot Scotland shows how to save money and increase potato yields

Reducing nitrogen without reducing yields

Once more SPot Scotland has shown you can vastly reduce nitrogen use without seeing any negative impact on yield or crop quality. In fact, we have seen better yields when less nitrogen has been applied.

Marc Allison of NIAB CUF explains: “We’ve almost halved nitrogen use at SPot Scotland and seen yield maintained or increased. Also, there is no impact on crop quality, we have seen no increase in black dot and no more bruising.

“You don’t need an ‘insurance application’ of nitrogen, just use what is recommended, otherwise you could be adding cost and losing yield.”

2018 results:

Trial no.1234
Planting179kg/Ha/N147kg/Ha/N90kg/Ha/N179kg/Ha/N
TreatmentTop dressStandard00Standard
Crop harvestedNo. Boxes/Ha69687058
Graded productTonnes/Ha.61616154
PACKOUT FIGURES*Packout % (useable)41%44%41%36%
Yieldt/ha28.529.728.720.7

Variable rate seed spacing success

While the results of the 2019 SPot demo plots did not show that variable rate planting improves yield or pack out, Bruce Farms have found it to be very useful.

Farm Manager Kerr Howatson used soil scanning on some of his more difficult fields, and then varied the rate of salad potato planting depending on the soil type.

More tubers were planted more tightly together in areas with heavier soil, and the result was a crop that was much closer to spec (under 42mm) than would have been the case otherwise.

Kerr says: “We’ve seen huge value in variable rate planting where you need to aim for a smaller size, for example with seed and salads. It really can make a big difference.”

2018 results:

Trial number:1234
TreatmentSeed rate33cm38cm47cmVariable
Crop HarvestedN. Boxes/Ha55625453
Graded productTonnes/Ha51575147
PACKOUT FIGURESPackout % (useable)51%43%42%42%
Yieldt/ha27.926.722.922.1

Cultivation trials prove less is more

After three years of trials it’s clear that a less is more approach is the way to go with cultivations.

Mark Stahlam of NIAB CUF explains: “Year on year the standard farm treatment has yielded more poorly than those treatments where bedtilling has been removed or cultivation depths have been reduced. Not only that, but the reducing cultivations saves time and money.

“I think the staff at SPot Scotland have seen that and are now only bedtilling parts of fields where it is really needed.”

In 2018 three cultivation trials were run using the following variables:

  1. Bedform 12”, Bedtill 12”, Destone 12”
  2. Bedform 12”, No Bedtilling, Destone 10”
  3. Triple bedtiller 12”
Trial No.123
Crop harvestedNo. Boxes/Ha535758
Graded productTonnes/Ha494952
PACKOUT FIGURES*Packout % (useable)35%36%36%
Yieldt/ha18.720.620.8

Source: AHDB