17 July 1998

Spray alerts

in advance

Computerised interpretation of on-farm weather data is

helping two Notts potato growers keep blight at bay this

season. Andrew Swallow reports

FORECASTING disease with on-farm weather data is strengthening blight control strategy and boosting confidence for Notts potato grower, Richard Birtill.

He manages 730ha (1800 acres) at Tiln Farms, near Retford, including 105ha (260 acres) of crisping, salad and ware potatoes. This year he is trialling the Plant Plus model on just 20ha (50 acres). But the experience has tightened management across the whole crop.

"It is forward-looking and gives an indication of when to spray. We get 48 hours notice to get on, rather than the you have just had an infection period, spray now advice of other models." Last June the latter approach resulted in blight infection, he notes.

Despite severe local pressure, Tiln Farms crops are blight-free this year, unlike some in the region, says Mr Birtill. In a different season, savings on sprays will be the main benefit, he believes.

"In a low risk season, with this system, we would have the confidence to stretch the spray interval to 14 days. Historically, once we started spraying, we would keep going at seven- to 10-day intervals."

The model correlates data collected by radio link from the in-field weather station with national weather patterns, to produce a detailed local five-day weather forecast. This is combined with crop assessments made by an agronomist, the date and persistency of previous applications, and the amount of fresh unprotected growth present, to give an infection risk prediction. Proactive action, rather than reactive, is the result.

Own-risk storage means nil infection is doubly important for Mr Birtill. The model also meets farm assurance requirements to show spraying is only in response to identified needs, he adds.

Investment in the system and weather station will be easily repaid, he believes. "In a high risk season such as this, we are only talking about a 5t/ha yield difference to justify the system in this 11ha of potatoes alone. Across the whole farm it would be far less.

"For me this makes far more sense than precision farming and soil analysis," he concludes.

Blight forecasting – typical

annual costs

£

Rent Adcon Telemetry auto

farm weather station 1000

(Or purchase £3500 inc soil

moisture sensors)

Dacom Plant Plus

forecasting model 500

Running costs (e-mail/fax data

transfers) 250

DMA specialist advice

on 20ha pilot service 475

Five day optional

detailed weather forecast 200

TOTAL 2425

Blight-free Maris Piper, thanks to advance warning of infective periods from the latest computer-forecasting model, says farm manager Richard Birtill at Tiln Farms.