26 January 1996

ADAS says use mapping now

YIELD mapping systems should be adopted by arable growers now, says ADAS.

Although it may be a few years before precision farming technology takes off, most growers will need that time to adapt, reckons senior arable consultant Brendan OConnor.

"The technology is developing rapidly. Perhaps 100 arable farms use it at the moment. But I believe it will be on all farms buying new, larger combines after the year 2000," says Mr OConnor.

The science will spread to root and forage crops as well, he predicts. "It will change the way we manage our arable crops and will lead to considerable savings."

Current prices may restrict interest to growers with 400ha (1000 acres) or more, says Mr OConnor. Yield mapping adds £11,000 to the cost of a combine and £4000 upwards for computers and associated software.

"But I would definitely expect it to come down in price, much as computers have," he says. The main drawback is the computing expertise needed. "Its one thing having the hardware fitted to the combine – its another learning how to use it correctly all the time. You need to be able to process, print, store and interpret data."

Farmers with no background knowledge in computing will need intensive training, he suggests. "It is an expensive toy. It has to pay its way by raising yields and cutting inputs."

Growers also need three to four years to gather enough information for accurate interpretation of yield trends, he adds. "Do not spend lots of money trying to correct a problem in year one only to find out it was seasonal."

Weaknesses in the system can also suggest problems where there are none (see box). "You only get one chance. If you make a mistake you cannot go back and combine the field again, or stop combining until you have sorted it out."

Machines that can vary rates of seed, pesticides, and fertilisers according to mapped information are still prototypes, he adds.

"But by the time yield mapping equipment is installed on combines as standard, engineers will have perfected them, allowing this infant technology to be exploited to the full. But will you be up to using it?"

&#8226 Readings less accurate when turning or combining around corners.

&#8226 Calculations assume full cutting width – careful driving needed.

&#8226 Turn off system when travelling over stubble.

&#8226 Less yield in tramline bouts easily overlooked.

&#8226 Try to combine in same direction each year to reduce errors.