SCOTS farmers are facing one of their toughest harvests ever with heavy rain and lack of sunshine sending yields of barley and oil seed rape plunging 30%, while livestock farmers are being hammered as the cost of feed spirals to its highest ever level.

The Met Office has confirmed the UK as a whole has suffered its wettest summer in 100 years.

Although Scotland fared better compared to the other UK nations, the statistics reveal farmers north of the Border have endured the seventh wettest summer on record with 384.6mm of rain since June and the 16th dullest summer with just 352 hours of sunshine.

The wet conditions have battered crop yields, with the latest indications showing that across the country 30% of barley and oil seed rape has been lost with the quality of what has been harvested poor in the case of barley and uncertain for oil seed rape.

The prospect of poor harvests in Scotland could lead to higher prices for whisky and food products, although poor grain crops in the US and Europe will have a wider impact on commodities such as bread and cereals over the coming months.

Andrew Moir, a grain farmer in Laurencekirk in Aberdeenshire and chairman of NFU Scotland's crops committee, told The Herald: "England are about a fortnight further on and their experience has been very similar and I think we're just heading for that experience on the winter feeds, for instance. We're losing 30% of our income, basically. Our costs are all spiralling upwards so to take a 30% hit in yield is significant."

He added that while the shortages were pushing grain prices up – barley selling for around £180 a tonne and oil seed rape for £360 to £370 a tonne – it was not enough to offset their soaring production costs.

"When you see the yield loss we've all experienced this year, it's been hellish. The higher price is obviously helping but our costs are escalating and it doesn't stop the price of fuel and gas going up. All the fertiliser we buy is also escalating by 20% to 30% just recently. So you need that 20% to 30% extra yield, which we don't have."

Frosts early in the season in continental Europe knocked out around 20% of milling wheat used for bread-making, while severe droughts in the US and Russia have wiped out vast quantities of feed grains used by farmers – particularly soya, which is now fetching record high prices on the global market.

Phil Sleigh, chairman of NFU Scotland's pigs and poultry committee, said: "For us, the UK weather is largely irrelevant. The problem we've had is the fact there's been a drought in the Midwest of the United States which was the worst in 50 years, and it's been dry in Russia and the Ukraine, so the supply of grain and soya is restricted quite a bit.

"Soya has gone up by about £200 a tonne in the past 12 months, from about £270 to about £470 at the moment.

"That's a real killer for the pig and poultry sector. I use eight tonnes of soya a week so that impacts pretty dramatically on my bottom line.

"The price of cereal is the same because of that same drought. The price of wheat has now gone up by about £50 a tonne in the past few months

"Soya has never been this high before. Five years ago we were paying about £140 to £150 and it just seems to have picked up and picked up, largely driven by weather but also by the expansion of demand in China.

"Half the pigs in the world are in China and they are soaking up soya from around the world."

Mr Sleigh, a pig farmer in Inverurie, said he and colleagues were now making a loss selling their livestock for around £1.50 per kilo, with an average pig weighing around 75 kilos.