ROUND AND SQUARE BALE SILAGE STORAGE

Transcription

1 ROUND AND SQUARE BALE SILAGE STORAGE Frank Mickan Pasture and Fodder Conservation Specialist, DPI, Ellinbank GENERAL HINTS FOR STORAGE OF ROUND BALED SILAGE Round bale silage dry matter (DM) content should be approx. 40% - 55% DM. Large square bales have been baled at higher (Up to 70%) DM contents but are most successful with high sugar type crops such as short rotation ryegrasses. Further research is needed into large square bale silage to discern which crops and at what DM contents they can be safely ensiled. DM and quality losses will be higher during harvesting and wilting due to the higher DM targets. Air is the greatest enemy of round bale silage. Bales should be tight and evenly shaped to ensure effective sealing and stacking. Loosely formed bales are difficult to handle, impossible to wrap/stack, and will contain too much air. This will result in wastage of 10% - 80% DM, heating, mould growth and quality losses. Manufactures produce a range variable chambered and/or fixed chambered balers suitable for making round baled silage. Many balers now also have the option of a chopping mechanism incorporated behind the pick up. Chopping results in approximately 10% - 17% extra weight in the same size bale. A combined flail chopper and baler can increase weight by about 20 25%. Regularly check plastic on all silage storages for damage caused by grubs, mice, sugar ants, birds, cattle, twigs, etc-reseal I M MEDIATELY. Repair tapes specifically designed for stretch film are now available. PLEASE NOTE: Plastic must be dry, free of dust, and cool for tapes to seal effectively over a long period of time. Cut the required length of tape and allow it to shrink before applying it to the hole in the plastic. Even small holes in stretch film will lead to substantial losses over time. The warmer the weather, the larger the hole, the longer the hole is left unsealed, the drier the silage, the looser the bale, the GREATER IS THE DETERIORATION. Ideally seal as soon as possible after baling, certainly no later than midday the following day. Loose bales will heat, lose quality and may be impossible to wrap if left overnight. If unable to wrap bales until the following day stand them on their ends overnight, especially loose bales, to ensure they hold their circular shape and not become unmanageable turtles. It is preferable to move the bales to the storage site before wrapping. Moving them after wrapping increases the risk of holing the plastic and possibly displacing the plastic layers and breaking the seal. Any method of storage is suitable provided air is excluded as soon as possible after baling. Losses of stacks of bales under sheet plastic tend to be higher (12-18%) compared to wrapped bales (5-10%). Holes in sheet covered bales lead to substantial losses (15-80%) if not patched immediately. Highly preferable to evacuate the air out of stack in this occurs.

2 Fence off storage areas securely. Discard any large amounts of deteriorated or mouldy silage. Do not feed any suspect mouldy silage to pregnant or milking animals, and definitely not to any class of sheep. If fed, offer it to non-pregnant or store type animals. Although unproven, and many farmers have fed mouldy silage to all classes of animals without mishap, mouldy silage has been suspected of causing abortions in cattle, sometimes deaths, and listeriosis in sheep. Silage film disposal is being addressed currently by the Silage and Mulch Film Task Force composed of Australian Plastics Manufacturers, plastics resin suppliers, Department of Natural Resources and Environment, and P.A.C.I.A. Details of the requirements for the storage and handling of plastic stretch wrap and sheet film for recycling will be communicated to the farming community when available. Until then plastic should be stored separately from netting and string in a clean, dry area with no contamination from metal, wood, etc. Causes expensive damage to recycling equipment. T YPES OF ROUND BALE SILAGE STORAGE 1. IND I V IDUALLY WRAPPED BALES (Stretch wrap film) Most effective storage system for round baled silage (losses~5% - 10% DM). Round bales should be tight, evenly formed, and barrel shaped. Allows effective wrapping, particularly in windy weather. Loose bales are difficult to wrap, have greater deterioration due to excess air trapped inside the bale, and are difficult to move and stack. Wrap using the system with 55% pre stretch i.e. bale is wrapped twice with 2 layers of plastic, each layer being overlapped by 1 / 2 width of film and is stretched on pre-stretcher by 55% (See Figure 1a). The pre stretcher is now usually pre set before leaving the manufacturer s plant. Be aware plastic formulations are constantly being developed by the manufacturers so read any new instructions carefully. An example is the production of Enduro, a plastic already pre-stretched before leaving the factory and requiring less stretch via an alternative set of gearing for most bale wrappers. Bales with too much stretch or not overlapped enough (See figure 1b) will not have enough UV inhibitor or plastic at all positions on the bale to prevent either plastic break down, or air entry. Some wrappers are able to wrap stringless round bales if bales are tight and placed on the wrapper so as to prevent unrolling. Even small holes in stretch film can lead to substantial losses. Use the specific stretch film tapes for repairs. Repair the holes immediately. It is preferable to store wrapped bales on their ends. Bales will maintain their shape. May be stacked two high if firm and even shaped. Less likelihood of bird, grub and mice damage. Many more layers of plastic on bale end so that if breakdown of the film (due to ultra-violet rays of the sun) occurs, damage may be reduced.

3 Bale Protection: To discourage vermin, store bales in bare areas which have been sprayed out earlier, or covered with sand, sawdust, etc. Store bales away from likely rodent homes, eg. not close to cereal growing paddocks, sheds, etc. Lay poison bait in the storage areas, preferably 2 weeks ahead of stacking and/or around the bale storage area, but not between bales as this may attract rodents into the storage area. Sprinkle lime on the ground surrounding the bales to deter mice. Wires strung at about mm above the bales or loose wires with silver plates, silver foil etc. attached have been reasonably successful in deterring crows and cockies. Tyres placed on bale tops. Tightly strung humming wires above bales. Painting large eyes or crosses on the tops of bales is reasonably successful. Removing the bales to nearby grassed paddocks immediately after baling can reduce bird damage as they are only searching for insects, worms, grubs, etc. which are more easily seen after the crop is removed. If you desire to store bales past one season:- Wrap with 6 layers of plastic instead of 4 layers. Turn the bales over after 6 12 months so that new plastic is now facing the sun. Place old plastic sheet over the bales but this provides a warm dry environment underneath for vermin, rabbits, etc. Store inside a shed but rodents may be a big problem. Bury in a silage pit for long term storage (preferable to individually wrap bales first). Do not try to wrap too many bales/roll of film. Table 1 indicates the numbers of bales (1.2m, 4 x 4 size) that should be wrapped for each type of film available, applying 4 layers (2 + 2, 50 + % overlap) with a film pre-stretch of 55%. Table 1. Number of bales/roll wrapped for a range of plastic film sizes Plastic Roll Size Approx. number of 1.2m x 1.2m (4 x 4 ) bales wrapped/roll 500mm wide x 1500m long mm wide x 1800m long 600mm wide x 1500m long 600mm wide x 1800m long 750mm wide x1500m long 730mm wide x 3100m long* * Enduro Gearing of wrapper may need to be altered to allow correct pre-stretch Up to 54 Bales which are longer or have an increased diameter may require more revolutions and result in lest bales/roll. Store unused rolls of stretch wrap on their ends to maintain the shape of the centre core and roll. Store out of direct sunlight, in a dry place, and away from heat sources. Store in a vermin proof container. Transporting unprotected rolls of stretch wrap to the paddock carefully - they are very easily punctured by sand, stones, wood, etc. in the back of a ute, resulting in substantial loss of film. Damaged ends of the roll may continually break during wrapping. Wrappers are now available for wrapping large square bales in stretch wrap film.

4 2. MULTIPLE BALE WRAPPING IN ROWS Machines are available which will wrap bales in single rows using stretch wrap plastic, with a saving of about 30% - 40% plastic compared to individual wrapping. The wrapper is set up at the storage site and bales are placed onto a platform by front end loader fitted with a suitable bale grab or spike. A bale or another immovable object is required for the initial bales to be wrapped to push against to start the row. Often a hay bale or an individually wrapped bale is used to form a plug at the beginning of the line. Stretch wrap plastic is placed on the bale and the bale is then left positioned in a line. The size of these stacks or lines can be of any length as the next bale to be removed acts as a plug to stop air movement down the line. Extra plastic may need to be wrapped where unevenly sized bales meet. This system uses the 75% overlap system, as shown in figure 1c. Try to avoid facing the rows where prevailing winds can blow under the plastic wrap. Both round and square bales can be wrapped with this type of wrapper. Figure 1: Correct and Incorrect Methods of Wrapping a. Wrapping showing correct overlap: RECO M MENDED, % +~25M M overlap, 55% stretch. -Even if water enters first layer, it s almost impossible to penetrate further. b. Wrapping showing incorrect overlap: AVOID, 2+2, <50% overlap, or 70% stretch. -It is possible that only 2 layers of film wrap may cover the bale in certain positions - not enough to keep air out! -Far greater and quicker losses if ultra-light radiation causes breakdown of the plastic.

5 c. Wrapping showing 75% overlap: AVOID 75% overlapping if possible. -At any point water/air needs to enter the width of one layer to reach the bale surface. 3. SINGLE ROW OR DOUBLE ROW SAUSAGE Less effective than individual wrapping (losses ~12-18%). Seal must be maintained, huge losses if holed or flapping plastic cracks. Lay bales end to end on their sides. Rip the ground along one or both sides before stacking to allow quicker and easier sealing when stacking is completed. May be possible to lay bales on one edge of the plastic cover as per Figure 2. In double row stacks, use tyres or dirt to prevent flapping of plastic. This prevents pumping of air into, and through the stack. Alternatively, stand bales on their end and stack tightly to exclude air (Figure 3). Seal only enough round bales for 5-7 days of feeding. Larger stacks will deteriorate quickly over longer feeding periods due to air gaining access the entire storage area. Due to their rectangular shape, enough large square bales of silage for days feeding may be sealed in each airtight compartment. Bales need to be evenly shaped and similar in size to minimise excessive air being trapped between bales. Feeding out equipment must be able to handle out of round bales if stored on their sides. Use polythene plastic designed for silage storage eg.6m x 50m (other sizes are available)-builders plastic is unsuitable, unless covered with dirt. May get 2-4 years storage if plastic is not holed and stored out of direct sunlight between seasons. Protect the new plastic by covering it with the older sheet to extend plastic longevity.

6 Figure 2. Single/Double Sausage Dirt or tyres minimise flapping Soil prevents air entry Plastic doubled over - easier pull out Figure 3. Bales on End Tyres minimise plastic flapping Minimise air trapped between bales Bales maintain shape Dirt seal 4. PYRAMID OR TRIPLE ROW SAUSAGE Less effective than individual and multiple wrapping and single rows (see Figure 4). Holed plastic results in large losses even if quickly patched. Evacuate air with a pump before patching with specific tape for silage plastic. Rip the ground along one or both sides before stacking to allow quicker and easier sealing.

7 Lay bales end to end. Bales must be tight, evenly shaped and of similar size to ensure maximum air exclusion and to enable safe and easy stacking. May be able to lay bales on one edge of the plastic and seal as shown in Figure 4. Need equipment to lift centre bale onto/out of the stack. Seal enough bales for 5-7 days of feed only. Use plastic designed for silage storage (eg. 6m x 50m, UV treated). Plastic should be weighed down on either side of top bale with tyres and connected over the top with a rope, baling string, etc. May get 2-4 years storage if plastic is not damaged, stored away from direct sunlight between seasons, etc. Figure 4. Pyramid/Triple Sausage Tyres tied together to minimise flapping. Minimise air entrapment Dirt seal 5. PIT STORAGE OF BALED SILAGE Effective if well packed, compartmentalised, and if well sealed. Seal stack completely around all sides (See Figure 5). Seal only 5-7 days feed into each compartment (Figure 6), unless bales are well rolled by a tractor to exclude air pockets and air passages into the length of the stack. Could possibly bale some ½ bales or use loose pasture as filling to minimise humps on the top to allow rolling. Bales will badly misshapen. Possibly evacuate the stack before sealing, but do not overdo the suction-may cause puncturing of the plastic. Large square bales are suited to being stored in pits, if sealed well and plastic is weighted on top. Use proper silage plastic (eg. 6m x 50m) (other sizes available).

8 Weight plastic down with many tyres, soil, or soil plus grass seed to prevent flapping. Feed out machine must be able to handle odd shaped bales. Seal the edges extremely well and any holes immediately - even small holes will lead to large losses. Figure 5. Methods of Sealing in a Pit Folded plastic Tyres or soil to prevent flapping Sand bags Dirt seal Figure 6. Sealing Compartments of Round or Square Bales in a Pit Tyres Overlapping plastic

9 6. PLASTIC BAGS (Two bales) Effectiveness can be very good to extremely poor (losses %). Double bale polythene bags available. At the storage site place the larger diameter bales in bag first to expel excess air, then put in the second bale. Must be extremely well sealed. Tie off the end, double over and retie tightly. No need to suck air out unless bales are significantly smaller than the bag. Most bales tend to expand from internal gas pressure - do not encourage the gases to escape by holing the bag. They will deflate themselves over time but watch for burst bags. Loose bales are unsuitable because of the large amount of air trapped in the bale - may be worthwhile evacuating these types of bagged bales. Holes in bagged silage generally lead to heaps of compost unless attended to immediately. Preferable to evacuate some of the new air. Do not store under trees. Watch for rodents, birds, etc. Feed out machines must be able to feed out bales with a flattened side. 7. STRETCHABLE BAGS/SOCKS Machines are now available which allow round bales to be placed into large plastic bags or socks. The machine, which stretches the diameter of the bag/sock by hydraulic rams, is set in place at the storage site. Bales are then placed by front end loader, fitted with a suitable bale grab, onto the machine s platform. They are then fed into the bag/sock after which the plastic bag/sock then retracts onto the bale resulting in a very close fit, and minimal entrapment of air. Bales of differing diameters will allow air to be trapped around the smaller diameter bale, leading to mould growth or some decomposition in that area. The plastic contains ultra light inhibitor and is thick enough to last 2 3 years, possibly longer, if necessary. For further information contact: Frank Mickan, DPI, Ellinbank, Phone: H:Silage Round Bale Silage Storage