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Optimal grassland use is first and foremost focused on the exploitation of the crops: next to the leasehold rent or leasehold claims, these include additional costs such as professional association membership fees and shared syndicate costs. Beyond this, the costs for the necessary and recommended cultivation of grassland with complementary seeding and the appropriate manure amount to a sum total of 400 – 500 €/ha in outlays. Depending on the yields, this involves a basic cost of ca. 15 €/t of forage. Separate from yields, the grass silage crops need mowing, windrow turning, swath broad-turning and swathing. For the purpose of the calculations below, mowing with a combine harvester (working width: 8.5 m), windrow turning using a 10-rotary tedder and turner (working width: 11 m) and swathing (working width: 12 m) are considered on a par. Mowing, windrow turning, swathing using your own or syndicate farm resources also serve to step up production costs which must be estimated at 5 – 6 €/t of forage. Harvesting and transport are contingent on the harvesting procedures used and the transport distances involved. To date, ensiling grass with short-cut silage trailer is the equipment of choice of single farms for smaller land surface areas. However, its modest shock power and the cost of investment involved in the farmer’s own harvesting chain is no longer able to keep up with the nutritional-physiological requirements of today’s high-performance cows, on the one hand, or the economic framework parameters, on the other. To handle one-day ensiling, high-performance rotational feeders mounted on large-capacity loader trailers are now available, offering storage capacities from 25 up to 40 m3 with prices starting from 40,000 €. With tractors as of 150 hp, only high yields allow for this type of capacity to be fully used. With these types of machinery, it is difficult to see how optimal price-performance ratios can be guaranteed for individual farms or even syndicated farms, thus the need for higher capacity utilisation. But the loader trailer still has a couple of key benefits up its sleeve:
Depending on the farm and the land plot structure, operational costs per tonne of silage are ultimately the decisive criteria. These criteria are essentially determined by scythe form as well as scythe size and the distance between the farm and the field. The shape, size and position of the scythe are what determine high efficiency – i.e. the labour portion of total field time. The shape of the scythe, even when equal in size, can make a difference of up to 20 % in terms of practical hectare performance. Working widths / swaths of 7m at a 9 km/h working speed and unfavourable land plots can only handle 4 ha/h, and up to 4.8 ha when using a more favourable shape - a difference which continues up to working widths of 15m. But that is not the problem for contractors or the local machinery syndicate. The question here is much more whether to go for a loader trailer or a chopper. Loader trailer Vs chopperThe new generation of loader trailers with rotating feed drums of up to and in excess of 40 meters and theoretical cut lengths of up to 35 mm enable high compaction, requiring net loads from 10 up to 14 t with capacities of 30 up to 40 m3. These harvesting engines which cost anywhere from 40,000 up to 75.000 € can be used for silage harvesting as well as for maize harvest chopping transports. The type of driving forces required for such capacity utilisation range from 150 hp and far beyond 200 hp. The cut lengths reported thus far are very promising. The decisive cut length range from 0 up to 80 mm still covers around 75 % of the total mass. By comparison: in this segment, a 5-scutching loader trailer at best manages a 50 % cut length ratio. Choppers have 100 % of their cut length in the 0 – 80 mm range. Consequently, the new feed and cutting systems fall somewhere in between. High load capacities, good compaction and maximum cut quality require power. To enable load capacities of 160 t/h, only 80 up to 100 kW power take-off will do, which must be augmented with the power required to drive the tractor/trailer combination across the land. To be able to even come anywhere close to handling this type of potential operational work load, tractors starting from 120 kW are needed. Improving cut qualityIn order to further improve the cut quality whilst moving up to the kind of cutting offered by choppers, at least 200 up to 250 hp driving power is needed for a 35 mm cut. Evenly shaped swaths with high swath strength of at least 10 kg here too are only worth the investment on high yields. Compared with the chopper, the loader trailer has the added benefit that the location/scythe switch barely reduces harvesting performance. Still, the loader trailer does have its limitations: the farm-field distance. The expensive loader trailer is competing with the more reasonably priced chopper-transporter, given an increasing portion of transportation duties. Consider farm-field distanceGiven a 2 km farm-field distance, a swath strength of 10 kg and a 10 km speed when fully loaded, at just 5 €/t, the cost benefits are marginally greater than the just 6 €/t for the loader trailer. These ratios tip the balance in favour of the chopper when – at this price difference - the chopper also manages to offer the best swath strengths whilst also covering greater farm-field distances. As of 4 to 5 km farm-field distances, harvesting costs move in the favour of the chopper, in spite of consistently higher land area performance/hour. What may be limiting however could be the loading capacity and the transport distance on the one hand, and the ensiling costs on the other hand. Because, compared with chopper silage, the possible compaction may be less and, as a result, the need for greater silo room and film. Depending on basic costs – either 50 €/m2 or 100 €/m2 silo room – sheer silage costs for rolling, silo, foil, protective nets, sand bags and coverings add another 9 to 13 €/t. With higher compaction rates of up to 10 %, the costs for chopping silaging are also proportionately less. The chopper is a must for maize harvestingThe question is why this tried and tested technique is not being used for the harvesting of grass as well. Which explains why in many regions the chopper already rules supreme when it comes to grass silaging. The benefits speak for themselves:
For the farmer as the potential buyer, all of the above are familiar criteria and arguments. But which criteria are decisive for the individual farm? Shock power or costs? High shock power and low costs are rarely compatible. Swath weight is a critical criteriaAs choppers invariably involve the combination of the chopper plus transport unit and the two drivers preferably operate in sync, attainable work speeds are limited. The perfect speed would be anywhere between 8 to 12 km/h, without causing added stress or seeing a rise in the rate of field loss. More than anything else, harvesting operations are affected by swath strength. Assuming a 35 dt dry mass yield per ha (corresponding to 2 – 2.4 kg of fresh grass per m2), a wilting level of 35 % will result in a wilting mass of 10 t/ha or 1 kg per m2. Given swaths of 7 m, working width is set to offer swath weights of 7 kg per m². At 8 km/h, in theory harvesting efficiency rates of 56 t/h can be attained. Deducting relay, turnaround and idle time leaves a harvesting performance of 34 t/h. Increasing speed up to 10 km/h results in a theoretical performance of 70 t/h, effectively leaving 42 t/h. Increasing swath strength up to 10 kg/m not only serves to step up swath strength by over 40 % but also increases harvesting performance from 56 t up to 80 t/h, which effectively means from 34 t up to 48 t. If higher speeds can be attained when fully loaded, harvesting performance increases proportionately. There is a good reason why the new 4-point medium rotary tedder is currently booming. With a 12 up to 15 m working width, swath strengths from 12 up to 15 kg/rm can be reached. The experience of contractors and machinery syndicates shows that harvesting performances dramatically improve. At a speed of 8 km/h when fully loaded and even tedder shape and strength, at 12 kg/rm, 58 t/h or 72 t/h at 15 kg can be attained. Certainly up to 7.2 ha/h. Obviously, this shock power is contingent on optimal transport logistics. Which in turn depends on the farm-field distance. At a distance of 2 km and 10.5 t of payload, 3 transport units are needed to reach this high shock power. Which are actually absolute peak values considering that the chopper only manages a max. 70% of its theoretical efficiency rate due to manoeuvring and unit and location switches. Which in itself is already very favourable. Our own tests have shown results between 45 and 75 %. Which is why, in order to attain favourable capacity utilisation at acceptable cost levels, good swath strengths and big scythes are required and land plots should ideally not be scattered. Supposing a cost of 180 €/h for the chopper and of 65 €/h for a transport unit, harvesting costs amount to 50 €/ha, i.e. just over 5 €/t without rolling and without silo storage costs in the best case scenario. Alternative bale silage: round, rectangular or in twin packs?Bale silage is fast gaining increasing support and can make good sense in specific situations. Although obviously not for the total grass silage crop. This is because a bale measuring 1.20 m in width and 1.25 m in diameter has a volume of just 1.5 m3 and at compaction densities of 180 - 200 kg dry mass and 35 % wilting ratio has a weight of ca. 800 kg. Adding 15 € incl. VAT for pressing, wrapping, transport and stacking, this drives the cost of a tonne of silage, carriage free from the storage house, up to close to 19 €. The kind of high costs which the chopper / loader trailer only reaches when operating under farm-field distance conditions of over 10 km. Bale silage is profitable under the following conditions:
Which is why a baling press can be of interest for contractors as a complementary tool for the operational conditions detailed above. The same also applies to the rectangular baler. Here, however, there is an interesting alternative when ensiling in twin packs. Using twin pack ensiling - in which two packs are stacked on top of each other before being wrapped – allows for larger bale dimensions. Two stacked packs from 1.6 up to 1.8 m in length combine to produce a single pack that is 1.20 m in width, 1.40 m in height and 1.6 up to 1.8 m in length. These stacks have a volume of ca. 2.9 m3 and a mass from 1.3 up to 1.6 t. Assuming 25 € incl. VAT per stack for pressing, wrapping and stacking with a telescopic loader, costs are around 18 € per t, without loading on the field and without transport – a system well worth considering by farms that have large tracts of land and long farm-field distances to cover. As applies to round bales, cut qualities fail to come anywhere near those offered by the loader trailer, especially as they also involve pass-out technology relying on hoisting appliances. As an alternative to twin packing, round or rectangular bales can also be clamped with stretch film as part of hank processing. This allows for further cost savings, although it is worth pointing out that this involves a higher quality risk in terms of potential moulding compared to twin pack ensiling. ConclusionsIn the case of scattered land plots and a small scythe size, the loader trailer is a valid alternative to the chopper. Given said conditions, the loader trailer is capable of high harvesting performance, utilising the available swathing techniques, and offering favourable processing costs. Good cut quality and high compaction at high net loads however require the use of powerful tractors starting from 150 hp. The limits of the processing costs are determined by hourly costs. At 100 €/h, the threshold point lies at a farm-field distance of 7 up to 8 km. If costs go up to 130 €/h, the threshold goes down to 4 to 5 km, as otherwise the portion of transportation duties of the loader trailer is paid for too dearly. The benefits of the chopper include its high hourly harvesting performance, which requires a proportionate swath strength, scythe structure and logistics. Round bale / pack ensiling acts as an alternative when facing considerable distances and low harvest volume - a complementary activity which is well worth considering by contractors and machinery syndicates next to hay and straw harvesting. Hanking should be approached with caution due to the potential quality risk that is involved.
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