Agco says its SCR technology will cut fuel consumption by about five percent compared with equivalent engines using alternative emission reduction systems.

As well the company says there is no need to compromise efficiency by altering the timing to reduce combustion temperatures on engines using its SCR after-treatment.

It continues to stress its SCR system is less complex than alternative internal and external exhaust gas recirculation designs and, furthermore, doesn't require any additional cooling packages.

So expect to hear a lot more when the first tractors in the world to feature SCR engine technology - Massey Ferguson's 8600 range – begin to strut their stuff on Australian farms.

Meanwhile, John Deere has just announced the new methods it will be using to meet the stringent Interim Tier 4/Stage III B mobile off-highway emissions regulations.

For all its 56kW (75 hp) and above engines Deere says NOx control will be achieved using its cooled exhaust gas recirculation (EGR) technology, adding an exhaust filter to reduce carbon monoxide, hydrocarbons and some particulate matter.

Claiming to be the first engine manufacturer to widely commercialise cooled EGR and variable geometry turbocharger technologies in off-highway applications, the company says it is well placed to meet the increasingly stringent North American and European emissions legislation.

Its director of worldwide marketing, sales and customer support, John Deere Power Systems’, John Piasecki, makes the point John Deere has elected not to use SCR technology which will require tractor users to manage a separate tank as part of its urea injection system.

New Holland is taking another tack, launching its prototype NH2 fuel-cell tractor at the recent French SIMA show where it garnered world-wide coverage for an initiative aimed at freeing up farmers from being dependent on fossil fuels.

Fuel cells within the NH2 tractor look to be a key ingredient of the system since they must transform hydrogen into the electricity that ultimately operates two motors – one driving the tractor, the other the pto, also the auxilliary services.

With no gearbox or clutch, or combustion engine and the only emission being water (a by-product of the workings of the fuel cells), there is talk of another two years of testing with production another two years down-the-track at which point the focus almost certainly will be the cost.

Factor in, too greater reliability due to fewer moving parts and, interestingly, the replacement of hydraulic systems and mechanical drives with electrical ones – for powering electrically-driven implements like planters and fertiliser spreaders - to begin to understand the revolution sitting beneath a commercial version of an NH2 tractor.

New Holland’s top tractor expert in Australia, Simon Vigour, gave a "big-picture" insight into why the company is committing itself to such an ambitious product.

He says with fuel and energy consituting such a large amount of farm inputs, the diverse location of this country’s farms also means that producers have to factor in extra costs associated with transporting fuel and energy to their far-flung properties.

He reasons that farmers in the future will be asked to take a fresh look at the large amount of space associated with their properties, possibly earmarking portions of them for generating their own energy - to run both the farm and associated equipment.

While New Holland's futuristic "Energy Independent" farm concept will still need electricity to electrolyse water into hydrogen and oxygen, the suggestion is that properties would be an ideal venue for producing electrical energy for free, courtesy of wind, solar, waste or biomass sources located on different parts of a property.

Interestingly, John Deere also looks to be a player in diesel-electric engine developments too, championing its 7430E and 7530E Premium tractors in Europe where they will be equipped with generators designed to power electrically-driven components.

First seen at the 2007 German Machinery Fair in Hanover, a statement from Deere's UK headquarters says these 123kW and 134kW (165hp and 180hp) tractors come with flywheel-mounted generators, suggesting they are the first commercial examples of on-board electrical power being utilised to improve operational efficiency - both of tractor systems as well as driving, potentially, a raft of implements and ancillary equipment.

When stationary power sockets will allow the operation of most handheld and fixed tools commonly used in both agricultural and industrial applications. In the wake of this development German farm machinery maker Rauch, recently debuted its electrically-powered fertiliser spreader, denoting how implement manufacturers also are keenly aware of the giant strides in engine technology being undertaken by the world's leading tractor makers.

Meanwhile, Steyr in Austria, part of the Case IH empire, has just announced details of a standard tractor that is powered by biogas, mirroring rival attempts to encourage farmers to produce fuel on their properties.

By converting a Steyr CVT 6195 tractor to operate with diesel, natural gas and biogas, fuel savings of up to 40 percent are possible, according to European managing director, Case IH and Steyr, Andreas Klauser.

"As one of the most innovative tractor manufacturers, we have a duty to develop alternative energies and technologies as innovations for our products," he said.

As can be seen in the accompanying picture, the biogas is filled into composite cylinders that are then mounted on the tractor chassis, principally the roof.

This innovative retrofit technology was designed by LuPower based in St. Andrä in Lungau/Salzburg which makes the point that because biogas is CO2-neutral as a fuel, this development is not just cost effective but also safeguards the environment.

Overall there is said to be a 17 percent reduction in NOx, 19 percent reduction in particulate emissions, while hydrocarbons are 87 percent lower, topped off by 97 percent less carbon monoxide being emitted.

While diesel fuel is still required as an ignition catalyst to run these engines, the quantity of biogas admixed to the combustion air can be regulated to "considerably reduce" the proportion of diesel required in the fuel mix.

"In Europe there is a large number of agricultural biogas plants, most of which are used to generate electricity," Mr Klauser said.