Taking on the role of a zero grazer a Krone forage wagon is proving a versatile tool for one Oxfordshire estate. Jane Carley reports.
The Krone AX250 forage wagon does double duty at Marston Estates, feeding dairy cattle on a zero grazing system and harvesting feedstock for an AD plant.
Needing to cut grass for zero grazing dairy cows and to supply feedstock for a 500kW anaerobic digester, Marston Estates, Oxfordshire, has found a forage wagon does both jobs efficiently and economically.
Plant Manager Carl Woolley says: “We need to cut about six to seven tonnes of grass daily in the growing season. Using fresh grass as feedstock for the AD plant reduces our reliance on rye and maize, as well as the need for extra storage capacity.
“It is too small a job to justify buying a forage harvester and would not appeal to a contractor.”
AD plant manager Carl Woolley harvests grass every day during the growing season.
The 150-cow dairy herd’s needs had previously been met using an old Bonino wagon, but it was becoming unreliable and could not provide the fine chop needed for grass going into the digester.
Bought in March 2015, a Krone AX250 forage wagon was specified with wide 600 tyres as the long cutting season from May to October meant it was often working in wet conditions. It was supplied by local dealer Farol, who matched it up with a 170hp John Deere 6170M tractor and a three-metre Deere 131 front-mounted mower conditioner.
“Another benefit of the package, compared to say, a second-hand forager, is it gives us another tractor fitted with wide tyres so I can use it for muck spreading, rolling and grain carting with minimal compaction,” says Mr Woolley.
After opening up the field with the mower and picking up grass separately, the AX250 is used in a one-pass operation behind the mower, also making it a one-man job.
“It is quite a long unit, which can make getting onto busy roads a challenge, but the Krone wagon’s low centre of gravity gives stability.
"We rotate grass leys on a two-year basis to help with grass-weed control. We have a field coming out of winter barley this autumn which is quite steep, so the wagon’s stability will be appreciated. It also follows the tractor well on the road.”
The AX250 has 32 knives which can be selected and activated from the cab, allowing Mr Woolley to harvest grass at lengths of 70-140mm for the cows first and then engage the knives to fill the wagon with chopped material for the digester. Theoretical minimum chop length is 23mm and as the body fills the extra compression improves the chop quality.
Dropping the nose of the wagon during loading helps get more material in. A drop floor also allows any blockages to be cleared without leaving the tractor seat.
Grass cut by the front mower enters the wagon via the 1.8m wide pick-up and is chopped to a theoretical minimum length of 23mm.
“Most harvesting machines are designed for dry forage, so we are impressed with how well the Krone works in wet conditions.” Mr Woolley says.
“A slightly shorter chop would be preferable for the AD plant, but instead we are fitting a fixed screen macerator to the intake hopper of the plant to put grass in at 10mm long.”
Capable of holding 12 tonnes fully laden, the AX250 generally chops six to seven tonnes a day, with 2,500t a year going into the digester and 1,000t to the cattle.
The chassis tips slightly to assist the walking floor when unloading. Forage is ejected close to the intake hopper for the AD plant and loaded with a telehandler, or simply tipped into the silage clamp on the dairy unit.
Leys are cut every 28 days so the material contains more leaf than stem. If conditions or workload mean the grass has gone too far it is baled for winter feed. The frequent cutting also means weed grasses never get chance to go to seed, also helping with black-grass control.
Unloading via the walking floor is assisted by tilting the chassis backwards slightly.
Mr Woolley says the forage wagon has proved durable so far with the low workload and minimal travel, with the forgiving conditions vindicating the choice of manual, rather than automatic sharpening.
“We are on clay soil so there are few stones and the blades stay sharp. We have had to replace a couple, but it is easily done.”
He says the heavier build of a forage wagon is more suited to the workload than a traditional zero grazer and should give a longer working life and increased resale value.
“We had a tight budget which governed the size of the machine and went for a basic specification. We did look at rear beaters to feed the forage directly from the wagon, but the buildings are just a bit too low.
"This is one of its few limitations. Due to the height of the wagon we cannot tip into the sheds so we need to rehandle grass for feeding cattle.”
A Pioneer additive applicator has been fitted so inoculant can be applied to any grass which needs to be clamped at the end of the season, increasing the gas availability in the digester.
Marston Estates has planning in place for a larger digester but development has been put on hold since it would require turning more of the diverse 1,000-hectare (2,470-acre) farming enterprise’s land over to forage crops.
Change is afoot in the future as HS2 will split the farm in two during the construction of a ‘green tunnel’.
A new generation joining the farm management could see the dairy herd increasing and Mr Woolley says thanks to the success of the zero grazing approach, he would favour a second forage wagon over other foraging methods.