Modern farms are embracing technologies that not so long ago would have been considered figments of a science-fiction writer's wildest imagination.

Farm work is increasingly being done by robots, while the cabs of combine harvesters, tractors and crop sprayers are packed with more computer power than early spacecraft had.

More and more dairy cows are being milked by stationary "robots". After some initial training, cows learn to voluntarily stand over the robotic milking machine. They are encouraged to do so by the prospect of having their udders relieved of milk as well as a measured portion of tasty, concentrated feed being offered to them from an automatic dispenser.

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Once in place, the robot uses electronic sensors to locate the cow's four teats, attach the cluster and then milk the cow.

Meanwhile, a computer recognises the cow by means of an electronic transponder fixed to her neck, records the amount of milk she gives and dispenses an amount of feed appropriate to her yield. It also knows not to feed a greedy cow that has come forward too often.

Such robots relieve the dairyman of the tedious routine of milking, allowing him to spend more time observing his cows and more time in the farm office managing the herd.

While computer technology is being used widely on livestock farms, it's the larger arable units that are in the vanguard.

There is satellite mapping of fields, showing variation in yields, soil type, moisture content and fertility that allow precision farming. Also under development are driverless tractors guided by global positioning systems (GPS), and unmanned aerial vehicle or flying drones fitted with cameras to check crops for diseases and weeds.

A state-of-the-art combine harvester can measure yields in different parts of a field and create a digital map. That allows the farmer to take soil samples from low-yielding areas and establish whether they need lime, or more nutrients like phosphates or potassium.

A fully developed digital map can then be used to programme a fertiliser spreader to apply varying quantities of fertiliser depending on the specific need in various parts of the field.

GPS technology offers farmers all kind of help. For example, even skilled drivers will have some overlap as they drive machines back and forth across an undulating, irregular field, which means for example spreading fertiliser twice in some areas, or leaving gaps.

GPS guidance can not only reduce overlaps from about 4% to 1%, but also calculate the most energy efficient way of doing the job, saving between £10 and £20 per hectare, never mind the environmental benefits.

Another advantage of such technology is that at the end of a day's work, a contractor will know exactly how much land he has combined, sprayed or fertilised and can make up his bill accordingly.

GPS technology also allows drivers to temporarily take their hands off the steering wheels and still drive in a straight line until they have to turn around at the end of the field – but now driverless tractors are about to go on trial in the US this year.

With their caterpillar tracks and lacking a driver's cab they look nothing like the tractors that we are used to seeing. They hold out the prospect of being less prone to accidents than a traditional tractor driven by a half-asleep student!

Perhaps the most exciting development, as far as I am concerned, are unmanned drones. Satellite images aren't as good when there is cloud cover, but low-flying drones can produce high-resolution pictures of the crop and its condition.

Different sensors – visible light, infra-red and thermal – are being used to identify different features of crops. Researchers have spent the last two years creating a database that will, for example, recognise weed types, the presence of disease, plant stress levels, crop damage, and crop yield potential.

Identifying weeds, their density and precise location within a field could, with a GPS-programmed sprayer, result in localised spraying and a big saving in chemical costs.

Similarly, by identifying chlorophyll content in the crop plants the technique could be used for variable-rate nitrogen fertiliser application.

While I don't believe that sheepdogs will ever be made redundant, there is also speculation that robots could be developed to locate and round-up livestock in remote areas.

That might be an advantage in places like the Australian bush, and more suited to unmanned drones rather than the piloted helicopters currently used for such work.