Scots reap the rewards from precision farming
By Peter McGrath
PIONEERING Scottish producers are benefiting from precision farming techniques in cereal and potato crops alike.
That was the message from farmer speakers at the First Scottish Precision Farming Conference, held at Kinross, Fife and sponsored by CSC Crop Protection, FWAG-Scotland and Scottish Natural Heritage.
Colin McGregor has tested precision methods for three years on 445ha (1100 acres) of arable land at Coldstream Mains in the Borders.
His retro-fitted RDS yield monitor has shown big variations in crop performance. "In one crop of Riband grown after potatoes the average yield was 9.6t/ha. But this varied between 3.7 and 12.1 t/ha, mostly due to soil type, with an area of heavier soil increasing yield by retaining more water," says Mr McGregor.
But care is needed to record areas damaged by rabbits or lodging, he warns. "You could be growing 10t/ha but the combine is only taking off 6t/ha."
Immediate savings after nutrient mapping half the farm mean the rest will be done this winter. Initially 230ha (568 acres) were mapped for P and K and variable spreading started this spring.
"The software was easy to use. But we had not made allowances for increased corrosion to the tractors when spreading from front-mounted hoppers."
Despite that spreading at the suggested rates reduced fertiliser costs by 33%, saving £2600. When the cost of the nutrient map is spread over five years the net gain is £1500, Mr McGregor estimates. Soil mapping also revealed pH differences across three fields. But no variable rate lime spreader was available. "We just marked areas in the field needing high or low rates with canes," explains Mr McGregor. "You do not need high-tech equipment all the time."
Analysis showed that only 20ha (49 acres) of the 38ha (94 acres) surveyed needed lime, almost halving use.
"The savings more than justify the investment," says Mr McGregor. Even after the cost of equipment, he claims annual savings of about £1600. "The benefits are there and should come through as increased yields over the next few years."
For potatoes, Jim Wilson of Hilton of Fern, Brechin, believes growing costs justify yield mapping. He estimates that accuracy of his Harvestmaster kit, fitted in just 3 hours, varies by just 1-4% – better than expected.
GPS also helps with the traceability of potatoes, which are loaded into bar-coded boxes during lifting. "It is now possible to select a 5kg bag of retail potatoes and trace it from the box to the field position and work out how much of which chemicals have been applied," he says. *