A Scottish Borders demonstration in late May emphasised why Krone’s BiG X line-up offers just as many benefits for grass silage producers as it does for maize. David Williams was there.
“Our harvesters are often the first choice for maize harvesting operations where the unique design features have earned a reputation for optimal work-rates and silage quality,” explained Krone marketing manager James Duggleby. “But our machines offer just as many benefits for grass and with standard and wide-body models and power from 490–1156hp there are versions to suit all user types.
“With target milk yields of 8,000-litres per cow and a climate unsuited to year-around grazing, it’s essential that forage quality is as good as possible whether it’s from maize or grass to achieve 4,000 litres of milk each year from fed forage.”
James stressed that good quality silage production is time critical as grass starts losing nutritional value as soon as it is cut, and that suitable chop length for the dry matter sugar content is an important factor. Like Krone’s OptiMaize concept for achieving optimum maize silage quality, Krone has also developed OptiGrass with the aim of efficiently producing good silage, free from contamination and prepared with consistent chop quality in whatever length is needed to suit the dry matter and use.
Line-up to suit
Krone offers 8 harvester models across 2 ranges – 4 with 630mm drum widths and 4 with wider 800mm drums. The new flagship BiG X 1180, launched in autumn 2018, is the world’s most powerful production agricultural machine with up to 1,156hp available from its Liebherr 12cyl, 24.24-litre power unit and in the past 10 years from 2008–2018, Krone harvester sales have increased 250 per cent in the UK and Ireland.
The company’s EasyFlow grass headers feature cam-less pick-ups and have six rows of tines in a W arrangement. Hydraulic drive allows step-less speed adjustment, either manually or automatically through Krone’s Synchro Speed mode which maintains an operating speed in relation to travel speed and ideal for variable conditions.
Two front gauge wheels and one central at the rear create a triangular pattern so that, regardless of the ground angle, all three wheels always contact the ground and the header can pivot to maintain even tine clearance across the working width.
“Consistent chop length starts with uniform feed,” stressed James, adding that from the standard crop roller which consolidates the swath for positive engagement by the pick-up tines to the six feed rollers, Krone’s system is all about chop quality.
Krone claims the lack of guide rollers and cam tracks means 58 per cent fewer moving parts than conventional headers, making it smoother running with lower wear rates and reduced operating costs.
The cam-less pick-up maintains a constant tine travel speed and the W tine pattern ensures a constant flow of grass for transfer to the intake by the large 600mm diameter cross auger.
Because Krone harvesters use independent wheel motors rather than a solid front axle, there is space between the front wheels for a larger intake chamber. Six compression rollers ensure forage is gripped securely, whatever its length, and fed evenly to the drum. As well as providing smooth and positive transfer of crop, the long feed chamber provides added protection from foreign objects. An 820mm travel distance between the leading roller which contains the metal detector to the counterblade provides ample time for drum rotation to stop before objects enter the blades. There is also protection from non-ferrous objects through RockProtect which uses an accelerometer to detect if the pre-compression rollers are forced suddenly apart by a foreign object. Sensitivity can be set by the operator.
When blockages are detected and the intake is reversed the cross-auger and crop press roller both lift automatically providing easy access to clear any obstruction. When work resumes, both return automatically to their working positions.
High capacity, reliable chop
Suitably chopped grass is critical to clamp construction and chop length must be adequate to maintain structure but achieve optimum consolidation for anaerobic fermentation. For grass with less than 20 per cent dry matter 20–30mm is suitable, but for forage with more than 20 per cent dry matter 10–20mm chop length is more suitable.
Drum options for grass include the MaxFlow, with 20, 28 or 36 blades and which can also be operated with half the blades removed extending the range of chop lengths available and for increased compatibility with a mix of crops from maize cut shorter for anaerobic digesters to grass. Blades in an 11-degree chevron pattern make full use of the 630 or 800mm drum widths for smooth chopping performance and crop flow. The drums of both standard and wide-bodied models are 660mm diameter.
One of the main design features is that the knives are attached to the underside of the holders rather than on top; providing twice the space to transport chopped material of standard knife mounting arrangements for higher throughput. Krone says the under-mounted design also reduces noise levels and drum wear, since all forage contact is with the knife body.
Adjustment of shear bar to knife clearance is automatic and set from the cab. A single ‘knock sensor’ is capable of detecting knife to bar contact across the width, providing information to two adjustment motors. Manual adjustment remains available.
To optimise potential work-rates, the drum base and accelerator back-plate are both spring-mounted to cope with uneven crop flow and allow clumps to pass through without blocking.
The drum base is linked to the shear bar so that as wear occurs and the shear bar is adjusted, the pre-set drum clearance is maintained through the season.
With fuel costs increasing, many of Krone’s harvester engines feature dual power curves allowing the operator to save fuel where conditions allow. In Eco-Power mode the BiG X 680, for example, produces 500hp, but in X Power mode output is up to 662hp.
Automatic selection adjusts output to match demand, but manual control is also available.
“The most efficient operating conditions are always with as large a swath as possible in front of the machine, and travel speed adjusted to make the most of chopping capacity,” pointed out James. “VariStream contributes to efficiency by allowing operators to push harvesters nearer their limits, knowing that if lumps in the swath temporarily exceed capacity the overload protection will operate preventing blocking.”
All BiG X harvesters are available with or without 4wd, but James explained that for the UK 4wd is considered standard. Independent rear wheel suspension allows the engine to be mounted lower in the chassis than if a common bar axle arrangement was used, and a further benefit is the 55-degree steering angle saving time on headlands.
Krone harvesters offer flexible additive dosing options including integrated coarse dosing from 0.5–7.5-litres/min, and fine dosing from 0.03-litres/min–0.25-litres/min and optional dose control automatically adjusts the rate to suit the yield. The on-board multi-tank system allows the user to allocate tanks for additional fuel storage, or increased additive capacity up to 505 litres.
Crop throw is adjustable from the cab, allowing fuel savings and reduced risk of crop spillage by reducing the throw distance when appropriate. To achieve this the back plate of the accelerator moves away from the impeller reducing crop contact with the paddles. For longer distances such as when opening up, to a trailer behind a tractor at the rear, the back-plate is moved closer so that forage is propelled with the full force of the impeller.
EasyLoad automatic trailer loading is an option using spout-mounted cameras to load trailers alongside and the operator can tailor the system for various loading strategies such as trailer front or rear first for maximum traction or improved visibility. Automatic filling at the rear isn’t currently available but will be added later.
Cabs are available in Premium or Premium Comfort specification which includes an uprated seat, and LiftCab is an option allowing the operator to raise the cab by 70cm to improve vision for work in taller crops such as maize.
The demonstration proved the ease of operation including quick adjustment and set-up through the control screen. Telematics to provide remote performance monitoring will be available later.
Approximately 320 Krone BiG X harvesters are manufactured per year to compete for a share of the 3,000-unit world market. Biggest demand is from Germany and the USA and Krone’s target is to achieve 20 per cent market share.
In the UK, the split between Krone’s wide- and narrow-bodied models is approximately 60/40 in favour of the larger machines.
“OptiGrass is our strategy for achieving good quality silage,” summarised James. “From the EasyFlow headers to the MaxFlow drums fed evenly by the six-roller intake, and VariStream allowing the operator to maximise work rates, the BiG X harvesters are designed to precisely chop forage to the required length quickly and efficiently, preserving quality for the best start possible to the clamp.”