Watch: John Deere 9900i, the latest powerhouse on the chop

Last autumn, John Deere brought out its new 9000 series range of self-propelled forager harvesters. The new series consists of four models, namely the 9600, 9700, 9800 and the flagship 9900.

The introduction of this series replaced two of the larger models in the 8000 series offering, namely the 8700 and the 8800. When designing the 9000 series, John Deere placed the emphasis on an increased horsepower from a new engine with higher throughput capabilities, while increasing overall machine efficiency.

Header

The pick-up on the 9000 series has been slightly beefed up in comparison to the header used on the 8000 series machine. This includes heavy duty chains, 30% heavier bearings, a 10mm thicker cutter-head shaft and extra wear strips and deck plates on the auger. Unlike some other manufacturers, John Deere has continued to use a four-tine bar pick-up reel with a cam track.

The header comes with a variable header drive. This feature automatically synchronizes the speed of the pick-up reel and the auger with the feeding speed and length of chop through a hydrostatic IVT drive system. This allows a consistent even crop flow back through the machine.

The pick-up reel also has a dual header drive. This system features individual hydraulic drive of the pick-up tines, matching their speed with the machine speed to help gather all of the crop off the ground. John Deere has included an auto coupler which makes it easier to attach and detach the header.

Feed rollers

Although some forager manufacturers recently opted to go for six-feed rollers, John Deere stuck with the four-spring loaded rollers. The 9000 series also has a hydraulic feedroll dampener beside the four rollers. This helps to keep a constant pressure on the flow of forage through the machine, allowing for a smooth feed of material to the drum. The 9000 series machines have an 850mm crop channel as opposed to the 660mm crop channel in the existing 8000 series, thus allowing increased throughput.

Like all forager manufacturers nowadays, John Deere offers a range of drums depending on the chop length requirements of the customer. The 9900i we visited was fitted with a 64-knife drum. It was running on a half set of knives chopping the grass to about 22mm. The machine comes with the option of four drums, each of which can run on 1/2 or 3/4 knife configurations for a longer chop length.

Engine

Surprising some, John Deere made the move from a 19l Cummins engine in the larger 8000 series to a 24.2l V12 Liebherr in the new 9000 series. This monstrous engine has a significant 970hp on tap.

The increase in power meant that John Deere had to include a beefed-up chassis and rear axle, along with a redesigned strengthened driveline in the 9000 series. The larger engine has been designed to run at lower speeds for increased fuel efficiency. This meant that the gearing had to be changed.

John Deere claims that at speeds beneath 1,400rpm, this engine provides high torque capacity and copes easily with peak loads. This Liebherr engine has an efficiency system that claims to optimise component speeds at low engine rpm. As a result, the driveline has a top speed of 1,800 rpm. From my time on the forager in Armagh, the engine was well capable of handling any load placed on it, but it must be said the crop was not overly heavy and thus the machine wasn’t under significant load.

The large engine is mounted longitudinally and the cooling pack is repositioned just to the rear of the base of the chute. John Deere has said that the longitudinal layout of the engine eliminates the need for the large and power-intensive cooling packages that transverse engines require. Essentially, more of the engine’s surface area is closer to the outer edges of the machine.

The idea behind the design is that cool air is drawn in through the channels behind the cab and is guided along the sides of the engine to the exits at the rear and the sides. This achieves more efficient cooling with less components. This engine comes with a 1,000-hour service interval. In fairness to Deere, the positioning of the engine allows for really easy maintenance. All panels open out to provide simple access to all filters, etc.

Although the top three models are powered by the V12 Liebherr, it’s worth noting that the 9600 is powered by a 13.5l John Deere PowerTech PSS engine.

Transmission

The forager is equipped with John Deere’s ProDrive hydrostatic transmission. This allows for automatic shifting across two preset speed ranges in which the operator selects a speed that will be maintained continuously in the field.

By pulling back the lever, two brake units, and the parking brake will engage automatically. If the wheels lose traction on a 4WD harvester, the hydraulic flow is automatically directed to the wheels that still have grip to help keep the machine moving. Travelling at a speed of 40km/h while maintaining an engine speed of 1,200rpm means the machine is very efficient on the road.

Harvest Lab

The 9900i has a lot in its favour. However, Harvest Lab is the one feature that I believe is differentiating John Deere from the other manufacturers, but this technology comes with a hefty price tag.

Harvest Lab is essentially a sensor that uses near-infrared (NIR) spectroscopy to analyse the various constituents within harvested crops. This same unit can be used in a forager, on a slurry tanker or it can be used as a mobile forage testing unit.

The unit is positioned in the chute of the forage harvester and takes real-time forage information as the harvested grass passes through. The unit takes over 4,000 measurements per second. This information is then compared with algorithms that are based on millions of hours of in-field experience.

The unit will provide the contractor or farmer with real-time readings on dry matter content, crude protein, starch, crude fibre, NDF, ADF, sugar and crude ash. This information can be taken one step further through the John Deere Operations Centre where yield mapping and an analysis of what areas of the field produced varying levels of crop constituents can be assessed. Variable-rate fertiliser spreading can be used based on the yield maps.

When using the unit on a slurry tanker, it has the capability of measuring N, P, K and dry matter. Before application, you can set a target rate for any one nutrient in kg/ha, a limit rate for a second nutrient and even a site-specific prescription map for any field. While spreading the slurry, the unit is constantly analysing nutrient levels. It will then automatically control the machine’s speed and/or flow rate to meet the desired target.

There’s no doubt that this NIR technology has the potential to be hugely popular in Ireland, especially with the significant focus we place on grass-based systems. However, at a price tag in the region of €20,000 plus VAT, will Irish contractors realistically make the leap?

Driving impression

The day we caught up with the 9900i, it was lifting 50ft swarths of third-cut silage on a dairy farm in Armagh. My first impression of the machine was that it’s an absolute beast. It’s evident the machine is built very strong all round. The forager is physically quite big, and John Deere paid special attention to tweaking some of the design features.

Inside the cab, there is an abundance of space and great visibility. John Deere incorporated some nice user friendly features such as the pro-touch function. This allows the operator to configure some of the controls to be synchronized at the touch of a button. We set the machine to change from road mode to field mode. In other words, by touching the button the forager opened out the pick-up guide wheels and moved the spout into working position.

One downside in the cab is the main control terminal is just 7” as standard, which is quite small. However, John Deere does offer the option to upgrade to a larger screen. Other than that, the control layout is very simple and easy to follow. The cab provided for a really nice operating environment. As the engine runs at low rpm, the machine works away very quietly.

The forager is an absolute beast to swallow grass. When picking the 50ft swarths, the 9900i was running out of comfort before it was running out of power. We picked grass at an average speed of 13.7km/h (8.5mph) while the engine was running at around 1,750rpm.

The pick-up seemed to follow the contours of the ground quite well, while the flow of grass back through the machine seemed consistent and even, despite the fact it was raked into big rows. The chop length was also very consistent.

Overall, the 9900i is a very capable piece of kit and an absolute powerhouse. However, the big question Irish contractors need to ask themselves if they are in the market for a new forager is that is this high horsepower required and can it be justified in this country?

Machine specs