John Deere 8120

Date: 07.12.2006

Mike Baker and his partners wanted a big, basic, tough tractor. They chose the 200hp John Deere 8120.

John Deere 8120

I have never seen a tractor work so hard. Mike Baker and his three equity partners run an extraordinary farming operation, with a very unusual history. They now have a huge operational dairy farm which, only two years ago, was entirely covered in radiata pine trees.

The partnership bought 450ha of forest from Carter Holt Harvey three years ago, adding another 120ha and then a further 540ha, to currently total 1135ha all-up. Located near Wiltsdown, in the South Waikato, general manager and partner Shane Wallace lives on site, and is also responsible for the 12 farm staff. Run as two farms, together, they milk 1750 Friesian cows - 1200 through an 80 bale rotary cowshed and 550 cows through a 54 bale rotary shed. What’s even more interesting is that the farm is still developing - there are 200ha of trees still to be uprooted.

Baker says that while 700ha of the property is mostly developed, they still have a way to go before both farms are able to utilise all of the land, as new pastures come on stream and existing paddocks improve. Cow numbers are ramping up each year and next season they plan to run approx 2700, topping out over the 3000 mark in 2008, after the installation of a third milking shed.

After 70 years and three forest rotations, getting the right infrastructure in place for a dairy farm must be a mammoth task. Fences must be built in kilometres rather than metres, water troughs are ordered and installed by the dozen - everything is done on a massive scale. The generous 5-6m wide races were built from the original metal-based forestry tracks, with a 200mm thick layer of Brilite added for the cows.

Parallel to the farming side, every day, an employed gang of four workers run a tree clearing operation. They operate a pair of Cat diggers and literally rip the entire tree out of the ground - stumps, trunk, and all. Initially, forestry contractors harvested the biggest logs by removing the whole tree, including roots, but now all that remains are sub 12 year old radiata trees, which luckily made up half of the forest to begin with. On paper, the developed portion of the property grows by 1.5 to 2ha each day.

The sequence of events begins with the Cat diggers pulling out each tree, followed by the 90hp John Deere 6220 fitted with grabbers to remove the tree and larger wayward slash left behind, aided by one of the diggers. Occasionally, this may be burned off first. The slash is tractored or trailered into large piles around the farm for later burning.

The day after the trees are out, the big John Deere 8120 comes along and mulches anything and everything left in its path, leaving behind a surprisingly smooth and well cultivated soil base. Then comes the John Deere 6920 with, firstly, a 4.5m wide heavy duty leveling bar and later discs on the same 150hp tractor. The next process is a roller followed by a fertiliser truck spreading a mixture of grass seed and fertiliser at the same time.

One of the very reasons the partnership chose to mulch rather than bulldoze, was to create a soil environment that would be ready to accept grass seed almost straight away, permitting almost instant use of the land once the grass, maize or beet takes hold. With the mulcher used to cultivate the soil, the woodchips help keep the soil structure together and the farm retains its rainfall. Steep hills don’t appear to have been a problem either.

Baker said they looked around and chose the 200hp John Deere 8120 because it was uncomplicated, cheap, and it would be tough for the job. "We wanted a big, basic, tough tractor. Walsh Motors (Cambridge) impressed us with their sales talk and have backed it up - we’re pleased with that," Baker explains.

It does the job but, after witnessing the absolute rugged kind of work it was doing, Baker says it would have been better if it had another 50hp. But then, other problems would have arisen, which have been a steep learning curve for the partnership. Everyday issues encountered on the job are inch-thick wire ropes left by forestry workers wrapping around the mulcher cutterhead. They had to replace the front tyres with heavy duty loader tyres because the tractor rubber couldn’t cope with the extremely rough, log-strewn terrain. To prevent the rear tyres from popping off their rims, they even had to weld a one inch steel pipe around each perimeter. The 8120 has been heavily guarded to protect the vehicle, such as a thick steel skid plate underneath the entire tractor, full steel plating around the fuel tank and particularly heavy fabrications protecting the front grill structure.

The mulching process can only be described as dramatic. From 3m away the ground shook. The 8120 must be the hardest-worked tractor in NZ, and is definitely doing things it wasn’t designed for. Extreme stress and strain is a normal day in the life of this big, long wheelbase John Deere. Every hour, the driver chews up huge volumes of soil, tree slash and even logs up to 200mm diameter or more are turned into pulp and mulch which are mixed up with the loamy soil.

So it’s no surprise either that the PTO drive has been rebuilt already. A shear bolt system is now fitted behind the PTO to stop the Walterschied clutch pack burning out. They blow a bolt each day rather than a $4500 clutch each week. After almost two years, the 8120 has already logged 3078 hours of hard-out use.

The turbocharged six-cylinder, 8.1 litre John Deere PowerTech diesel engine is intercooled and produces 200hp. The engine on our test tractor must be pretty good because when the 8120 is operated, the power plant is running at full 2280rpm the entire time the tractor is used, in order to keep the mulcher spinning. The driver engages the PTO, revs up the engine, lowers the mulcher into the ground and flicks it into the 1.8km/h first gear (16 forward and four reverse) with the small powershift gear change lever mounted near the armrest. The driver’s biggest task is to lift and lower the rear linkage when the mulcher begins to slow and lose its rotation speed.

I took the opportunity to drive it and I can truly say the 8120 is some workhorse. From the outside it looks like a machine from the Mad Max movie, while from the inside you feel almost invincible - a bulldozer on wheels. Little wonder they removed the front blade early on - they used it to push over the smaller trees and grind them up on the way past with the mulcher. They soon realised it wasn’t the fastest way to do the job, but not until they broke part of the front frame casting. That’s when they brought in the diggers to pull out all the trees.

Inside the roomy cabin is a super-soft two-way swivel ActiveSeat, which is designed to move in all axis to reduce jarring, which it does very well. Inside the uncluttered, simplistic cab all operational controls and gauges are situated on the right. There is no dash on the 8120, although the digital rev counter is mounted on the right hand pillar.

Because of their unique operation, Baker says they don’t use most of the control options available to them. Looking outside through the large, uninterrupted glass panels is no problem, while forward visibility to the front wheels is increased thanks to an engine bay which is narrower from the cab. The cab keeps the sound out very well too, as the mulching process must be one of the most noisy tasks ever performed by a tractor.

The land is too valuable for forestry and although there is a high cost to redevelop it, dairy farming is more profitable. The nearby Lichfield milk plant must also help.

"It is not for the faint hearted. You just don’t rock up and decide to do a forestry conversion. This is a seriously large scale farm for the Waikato, it involves a serious amount of money and it involves a serious amount of skill," says Baker.

"And you need the support of so many people. We need the support of our bank manager, the fertiliser experts, the seed guys, we need the support of Walsh Motors with machinery, and their ability to keep these things going. I don’t think anything has been hard, but the biggest thing has been having the vision to do it."

The John Deere 8120 is a massively strong tractor which has now been replaced by the more technologically advanced 30 Series model.

By Terry Stevenson

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