The carbon footprint of potato crops was not good and it’s the highest of the field-based crops, said Eric Anderson, senior agronomist at Scottish Agronomy.
He urged potato growers to look closely at their carbon footprint and said paying close attention to soil structure, soil management and water management would pay dividends for crop profitability.
At a time of escalating fuel prices, he pointed out that the two biggest influences within that footprint were diesel usage for mechanical operations and water usage within the crop.
And he said growers needed to understand their own carbon footprint and how they could make use of that information within the decision-making process within the business to save money and increase profitability.
“Collectively, you are spending more in a normalised situation on diesel and electricity (storage) than you’re spending on fertiliser and pesticides, yet how much time and attention are we paying to those two inputs,” he asked.
Typically, for crop establishment up to and including planting, diesel usage ranged from 88 to 205 litres/ha (£61.60/ha – £138/ha).
“There are alternative ways of cultivating the field and some are more efficient in terms of energy use than others,” he said.
Mr Anderson said the cost of ploughing, including tractor, diesel and labour costs, was around £70/ha, increasing to nearly £80/ha with a margin added.
Growers should pay attention to their soil structure and carefully consider the timing of ploughing operations, he added.
Either ploughing or cultivating when the soil was wet at depth could damage the soil structure and increase the need for additional operations and fuel costs, he said.
“Ploughing over winter in inappropriate conditions can cause pans (compacted layers), anaerobic soil and compaction, which can subsequently limit rooting under the potato crops, by as much as 50%,” he said.
Choice of tractor, including suitability for the job and fuel efficiency, were others influencing factors, he noted.
“Using a higher horsepower tractor, where available, by increasing forward speed and revs can make it more fuel efficient.”
Mr Anderson said damage to the soil structure would increase the need for irrigation if rooting was reduced.
But he added: “Applied irrigation will never fully substitute for the available water in the soil – and in addition it costs more money.”