Among the fields of technologies

GPS has been flagged up as a boon to cereal production

Advances in science and technology have brought both benefits and concerns for farmers, an NFU chief has said.

Stewart Wood said the Global Positioning System (GPS), which uses satellites to provide a navigational guide on the ground, has had an impact.

He said cereal growers were using GPS to help better target fields with artificial fertiliser.

However, moves to have all sheep fitted with electronic tags has met with opposition from farmers.

Mr Wood, who was seeking re-election as vice president of NFU Scotland at the organisation's AGM in Aviemore, said new technologies were being put to use across agriculture - in cereal, livestock and milk production.

There is now more stock but less people to manage it and that is where technology helps Stewart Wood NFU Scotland

He said: "The number of farmers today is less than half of what there were when I left school.

"There is now more stock but less people to manage it and that is where technology helps."

GPS has had a huge impact on cereal production over the last 10 years and Mr Wood said it was playing a part in how much fertilisers were used on the land.

Last summer, cereal growers in Scotland faced paying almost double the price they paid the previous year for fertiliser.

Colin Mason, chairman of the NFU Scotland's Highland region, told the BBC Scotland news website costs had risen from between £250-270 a tonne to £500-600.

Higher oil prices were blamed for pushing up fertiliser production costs.

But using GPS during harvests has allowed cereal growers to map where yields were at their highest or lowest, helping to target better where fertiliser was needed most.

According to the Scottish Government, the area of the cereal crop in Scotland increased to more than 983,000 acres (398,000 hectares) in 2007.

GPS FACT FILE GPS uses a network of satellites to provide navigational information for the military, but also civilian sailors, hillwalkers, and drivers In parts of Asia, conservationists have used a GPS collar fixed to an elephant in herds to help avoid clashes between the animals and villagers

North East Scotland and Tayside account for 52% of Scotland's cereals and tillage area.

Mr Wood said it was also helpful for farmers with fields in nitrate vulnerable zones (NVZs).

Farms located within the zones, which cover about 55% of the UK, are required to adhere to a set of measures to reduce the amount of nitrate lost from their land to watercourses and groundwater supplies.

Among the fields of science, livestock farmers have been using embryo transfer as a technique to improve the genetic quality of cattle.

It involves removing an embryo from a donor cow, deemed to have good genes, to a surrogate mother to give birth to and raise.

Meanwhile, sheep farmers have been opposing plans for compulsory tagging of stock.

With each tag costing up to £1.50, the aim of the scheme is to improve the tracking of animals from farms to where they end up in food production.

The European Commission (EC) argues the proposals are the best way of allowing "individual traceability" of animals.

In 2007, the EU Council of Ministers, which includes the UK Government, agreed on a regulation to introduce compulsory electronic tagging to sheep and goats.

Its introduction was initially postponed and eventually set for 31 December 2009, to give all EU countries extra time to prepare. The dates has since been shifted to 2010.

The NFU has warned that the electronic readers involved are often compromised by working conditions.

It has been estimated it will cost farmers up to 40% of their incomes to introduce the technology without any improvements to food safety or disease control.

The rearing of sheep is a major part of Scottish farming.

There were 7.4 million sheep on Scottish farms at June 2007, mainly consisting of 2.9 million breeding ewes and 3.6 million lambs, according to Scottish Government statistics.