Silage harvesting – manage the energy needs

Silage harvesting is among the most energy-hungry operations in farming. Contractors tell us that the typical self-propelled harvester will use a full diesel tank of close to 1,000 litres in a single day’s work.

The cost of filling the entire silage harvesting fleet on a daily basis can be frightening. The daily diesel volumes can quickly run to more than 2,000 litres when the full fleet is taken into account. That converts to an average figure of 20 litres per acre in a high-output 100 acres per day system, across a full season.

Many operators start the season with sharp blades and good adjustment. They need regular care to keep them sharp and working at their best. But it’s not just the harvester that needs attention; take time to keep the mower and loaders in good shape.

The potential savings must be fully exploited. The price of diesel cannot be influenced by the driver, but the level of consumption can. Even with smaller self-propelled harvesters, daily diesel consumption can be very expensive. At current diesel prices, a savings potential of 10% will deliver a significant reduction in the fuel bill.

Keeping blades sharp on mowers and harvesters will reduce the energy needed to cut silage crops. Drum and disc mower knives are typically subjected to higher rates of wear and are prone to more breakage because of their exposure.

Dull knives increase power requirements. Clean cutting not only requires less power, it also leaves a cleaner stubble that will re-grow quicker.

Check knives and knife bolts each day before mowing and immediately after striking an object. Replace broken, worn or distorted knives, bolts and nuts.

Laying the crop in a wide swath promotes faster drying and can reduce drying times significantly in good weather conditions, compared to narrow swaths or windrows. So you should aim to mow with the swath boards opened widely.

Some contractors are using GPS control systems to reduce the amount of empty runs of the mower. The systems can help to optimise the way the field is cut and minimise empty and short runs.

The way that the mower is used will often dictate the path of the following harvester, so aim to keep long runs with minimum turns, to ensure more efficient driving by the harvester team.

Tedding and raking

Rakes and tedders can be used to promote drying by turning windrows and exposing new surfaces to air movement and sunlight. Merging windrows saves fuel by better matching harvester capacity with crop yield.

Harvesters use less fuel per tonne of crop if they are operated close to capacity. If the harvester is picking up a single swath and not loaded near machine capacity it will not only take longer but also wastes fuel.

Silage harvesters

Three items have a significant effect on forage harvesting fuel consumption; these are the length-of-cut, knife sharpness and knife-shearbar clearance. The cutting energy will double as the blade edge wears from a 0.1mm (0.004 in) radius (sharp) to a 0.3mm (0.012 in) radius (dull). Research has shown that the harvester cutterhead power requirement also increases as the knife to shearbar clearance increases. The cutterhead power requirement will double for each 0.25mm (0.01in) increase in shearbar clearance.

The clearance can be caused by worn knives and worn shearbar or by knife sharpening. Each time the knives are sharpened, the shearbar must be adjusted according to the machines manual directions.

Roughly 40% of the energy used by a harvester is consumed by the cutterhead/chopper, so the effect on fuel consumption can be considerable from dull knives and worn shearbars.

No matter what silage harvesting operation you are using, the most important energy savings task you can perform is to properly maintain your equipment and tractors. Simple tasks like cleaning radiators, keeping air filters clean, properly inflating tyres, sharpening knives and checking clearances can each save fuel in small ways. This can add up to a more profitable cost per tonne of feed.

When making many of the adjustments discussed above with older and smaller machines, make sure to use safe practices including wearing eye protection when sharpening knives and having cylinder stops in place when adjusting roll clearance.

Save up to 15% fuel at harvesting

Fuel efficiency tests across Europe have shown the potential to reduce fuel consumption by up to 15% by more efficient operation of tractors and trailers in operations such as transporting silage.