27 July 2001
Manage moisture, spud growers told

By FARMERS WEEKLY staff

POTATO growers have been warned yield and quality could be hit if they allow soil moisture monitoring to take a back seat.

Nothing can replace regular moisture assessments, said research lecturer Ivan Grove at a recent British Potato Council Open Day in Shropshire.

These should be taken at least twice a week, to guarantee crops are safely within critical soil moisture deficits (SMD), he added.

“For maincrop potatoes an SMD of 35mm will impact on yield and quality, while common scab can occur with deficits of just 10-12mm.”

For earlier harvested crops the parameters are tighter, with a maximum SMD of just 25mm, advised Dr Grove.

“Despite the recent downpours, deficits can still accumulate quickly. Crops can easily lose 3-4.5mm a day through evapo-transpiration aided by a good breeze.

“Timed applications of 5mm water across the growing area should keep SMDs within critical levels. But growers are treading a fine balance all the time.

“If SMDs are brought down to very low levels and rain showers follow it could lead to run-off and disease such as powdery scab.”

Monitoring and accurate records may also become essential in future to safeguard water abstraction licences, which are increasingly coming under scrutiny.

“The Environment Agency now wants more information to support applications and producers will have to prove their case,” he said.