The development of baled silage in the 1980s was the first really novel change in a complete farming system for a generation.

Most other mechanisation developments are evolutions of earlier systems, but the packing and wrapping of individual silage bales was unique.

The development has been quite rapid, but are we at the peak of its evolution now?

What further developments are needed or likely to occur?

The beginnings – a summary

  • The first baled silage in Ireland was made in the 1970s using small square bales in clamps. AFT research (now Teagasc) was involved in encouraging haymakers to move to silage. It could make good silage, but output was low, losses could occur in storage (air pockets), and it wasn’t at all suitable for mechanical handling.
  • The big round baler spawned the development of early baled silage in the UK (Northumberland) with variable chamber balers of either chain-and-slat design (New Holland) or belt (Farmhand / PZ) used. The bales were either clamped into polythene-divided compartmentalised stacks, or placed in individual bags.
  • In Ireland, in the early 1980s, McCormack products (later Volac) and Killeshandra co-op (later part of Lakeland Dairies) sponsored five-belt-type balers and promoted a bagging system to get smaller farmers to change to silage from hay in Longford, Leitrim and Cavan. Bagging was labour intensive, slow and prone to heavy losses if the bag was damaged.
  • AFT (now Teagasc) began evaluation of the system in 1984 and used fixed-chamber balers (originally Krone and Welger) for the first time on silage. System work rates and other performance factors around all of the mechanical operations were assessed.
  • Stretch film wrapping was originally introduced with a hand applicator and PTO-driven bale rotator (Tanco) but a fully automatic turntable wrapper was introduced in 1986 (Kverneland/ Underhaug). This development ensured the success of the system, as it reduced aerobic loss risk and eliminated manual handling.
  • Both Tanco and McHale quickly developed effective turntable wrappers.
  • Teagasc research broadened to include areas such as silage quality aspects, wilting, polythene aspects, mould avoidance, costs, and comparisons with conventional silage etc.
  • Promotion by Teagasc, Volac and others focused on key management aspects but particularly:
  • Suitability as main silage system on small farms.
  • Flexible supplementary silage system on larger farms, maintaining high-quality forage in bales and high-quality grass in paddocks.
  • Lower fixed costs (simpler storage).
  • Costs associated with the quantity of forage conserved, thereby promoting good-quality silage rather than just quantity.
  • Requirement of high level of management to avoid losses, including: growing high-quality grass; adopting rapid wilting; baling firm bales; wrapping with minimum four (occasionally six) layers of film across all of bale circumference; avoiding damage during handling and storage, etc.
  • Baled silage adoption was rapid and became widespread across Ireland when the benefits appropriate for individual farms were identified. Baled silage has been made on most farms for decades now.

    • An early version of the Kverneland Silawrap machine in action, which was distributed in Ireland at the time by Volac Feeds.

    1. Mowing, tedding and raking

    While developments in mowing are mentioned in a separate article, a few specific points on baled silage are considered here.

    Who teds and rakes? In the early days of baled silage, some or all of the mowing, tedding and raking were carried out by the farmer.

    Now much of this is done by a contractor. While this may be cost effective and result in better swath presentation for today’s high-capacity balers, it can remove a key silage quality-control element.

    Wilting should be rapid and controlled to avoid losses and to get to the desired dry matter level to guarantee preservation, eliminate silage effluent and reduce bale numbers (and associated baling, wrapping and transport costs). Wilting must be rapid and coordinated with baling.

    Mower conditioners: Mower conditioners can set up a good swath with improved transfer of moisture from within the swath, but drying rate depends primarily on the width of swath compared to the area cut.

    For low-yielding crops (grazing paddock or second cut) in good drying, a mower conditioner alone set to occupy over 60% of the cut area (eg 1.7m wide swath from a 2.7m mower) may achieve a satisfactory wilt. But where grass is heavier, spreading the grass to 100% with the mower or tedder will be needed for fast wilting.

    Over-the-top tedders will promote drying by redistributing and aerating the material in the swath, but the drying rate is still mostly influenced by how thinly the grass is spread.

    Raking and swath size: Modern high-capacity balers with good feed intakes can cope with big swaths of grass.

    However, the aim must be to pack the bale as well as possible by balancing output with a slow enough speed for the swath size that guarantees a well-packed bale.

    2. Baling

    Round balers suit silage well as the bales are easy to wrap and they are cheaper to operate than large square/rectangular balers. Today’s balers have more durable drivelines to cope with the higher power of today’s tractors. Feed intakes have improved with good chopping systems and blockages more easily cleared ( drop-floor systems etc).

    Electronic monitoring and control of key functions, including the complete wrapping system on combi-balers, is now a feature of all balers. Some balers can automatically steer and control their left/right position on the swath in response to the density measurement at the baler sides.

    From a farmer perspective, the key baling target is to get as much grass DM packed into a bale as possible as this will influence most costs associated with baled silage.

    The big drawback of traditional round baler design is that baling stops to allow netting/binding and bale ejection or transfer to the wrapper element. Manufacturers have been working on two chamber designs for years to overcome this, with Kverneland (fastbale) being the most prominent on the market.

    This is marketed on a baler/wrapper combi unit, allowing non-stop baling and wrapping, increasing output and easing the task on the operator and tractor.

    Bagging bales was a tiring and labour demanding job.

    Combi-wrapping: Most silage baling today is by combined baling and wrapping units, saving labour and allowing one person to do both operations. Initial combinations trailed an auto-loading wrapper behind a baler.

    All baler and wrapper manufacturers now have integrated ‘combi’ machines with McHale leading the market in Ireland and across many countries. Newer units now incorporate film on film wrapping, which is logical as it provides an additional oxygen barrier film to bind the bale.

    However, this was not easy to develop, with current designs using quite a bit of film in a narrow tail at the start and end of binding.

    Wrappers: Wrappers, or the wrapping component on combi machines, have settled for some time on 50% overlapping with 70% pre-stretch, as efforts to use pre-stretched films etc produced a lot of confusion.

    We should be open to improvements here, but independent research would be needed to validate any alternative approach (film type, thickness, later number stretch etc).

    3. Bale handling and transport

    Bale handling and transport is labour intensive and a source of damage to wrapped bales. Single-bale transporters are still used on small farms. Double-rear bale transporters coupled with a front-loader handler can efficiently transport and stack bales where the storage area is adjacent to the silage field.

    For greater distances, the original practice of loading and unloading flat trailers has increasingly been supplemented by the chaser-type trailed bale transporters that can lift, carry and drop up to 12 bales at a time.

    These trailers need a lot of space to work around the storage area and great care is needed to avoid film damage in loading, unloading and stacking.

    Bales must be transported within hours of being made to avoid bird damage and particularly film damage when bales become misshapen.

    With all systems, film damage in the field, while handling, or in storage is not uncommon and there is a need for improvement.

    Storage site wrapping, where bales are transported before wrapping, and wrapped where stored by either a remote controlled stationary wrapper or a loader-mounted wrapper, can result in reduced handling and film damage risk. However, this system is less attractive to contractors as it would need a very well-structured transport system.

    Further developments in baled silage

    The biggest threat to the baled silage system may be the perceived sustainability of the polythene wrapping, along with the cost of the film.

    It is imperative that the circularity of the recycling system is clearly displayed, with all baled plastic recycled into as high a grade second-use as possible.

    Polythene use can only be reduced by packing more grass DM into each bale, so the pursuit of bales with more silage in them is important.

  • Larger diameter bales. a move to larger diameter bales may now be feasible with bigger capacity loaders and handling equipment. A 1.35m diameter bale would hold 27% more silage but use just 6% more film compared to a 1.2m diameter, while a move to a 1.5m diameter bale would contain 57% more silage and use just 13% more film. Larger bales would also be more efficient to transport. The downside would be the increased weight on smaller tractors or tractor loaders.
  • Alternative storage systems to save film:
  • In the early days, bales were clamped in polythene with ‘use in a week’ sized compartments created to reduce aerobic loss on opening. Polythene consumption would be lower if the polythene could be used for more than one season, but this system loses lots of the flexibility of individual wrapping and would require a very high level of silo management.
  • Tube wrapping was also a feature of early wrapping systems, where bales were placed on a wrapper which wrapped a continuous line of bales butted end to end. This saved up to 40% of the film which is normally used to wrap the flat bale ends. However, it requires a lot of storage space and is less flexible than individual wrapping.

    • Alternatives to fossil-fuel-based wrapping polythene are feasible, but developing a suitable product for this use will be challenging and expensive.

    Most silage baling today is done using combination baler/wrapping units such as the McHale Fusion which has took the market by storm since its inception. \ Donal O'Leary

    Clamp silage for small quantities

    There is no doubt that baled silage proved a great ‘disruptor’ to conventional silage as it virtually eliminated all lighter silage cuts (second cut, additional paddocks etc) as well as picking up all of the silage on smaller farms.

    If polythene cost and use became a more serious issue, conventional silage could regain some of the baled silage market. But to do that, the clamp silage system would need to have:

  • Better yield-dependent pricing model.
  • A greater proportion of smaller machines suitable for lighter cuts and smaller cut volumes (more wagons?).
  • Farmers with more flexible clamp storage facilities more suited to conservation and use of smaller quantities.

    • Purpose built bale chasers have become a common method of transporting bales. \ Donal O'Leary

    Kverneland were the first to market with a continuous round bale wrapper, meaning the operator does not have to stop during the binding process.