Case Study 1

600 ha home farm covering a range of soil types from clay through to sandy loam. Annual average rainfall around 650 mm. Table 1 provides details of the machinery used in the arable operation which grows a rotation of first and second wheat with oilseed rape. The aim on this farm is to create a 6 m CTF system using a single pass with the nominal 6 m wide medium weight discs followed by drilling with the 6 m Freeflow drill. Within the new CTF farming operation it is anticipated that there will be little need for the Solo, and this demonstrates an immediate saving in equipment, time, fuel and tractor power.

Machines used in the establishment, care and harvesting of the wheat and oilseed rape

Machine Wheel/Track gauge, mm Track/Tyre Width, mm Overall machine width, mm Operating width of implement, m
Claas Challenger 2330 760 3060 N/A
Simba Series 2 discs 2280 670 2950 6.26
Simba Solo - discs with integral subsoiler       4.0
Simba Freeflow Full width tyres 6.0
Sprayer 1 1981 650 2631 24
Sprayer 2 (Agribuggy) 2000 550 2550 24
Claas Lexion 480 combine harvester 3048 752 3800 9.14
Horsch Chaser 2150 720 2870 N/A
Fendt 716 tractor (to pull Chaser) 1830 550 2380 N/A

The figure below shows how the CTF range of equipment creates a wide overall footprint for the wheels. However, the most frequently used tracks will be those of the sprayers, and the 650 mm shown as the principal width of the tramline (shaded grey) is based on these two vehicles. Although this is not an ideal situation, it is easy to see that the long term objective should be to match all wheel gauges. Probably the most effective would be the gauge of the Fendt tractor, but the cost and complexity would need to be judged by inspection of the individual machines.

The other greatest anomaly is the 9.14 m cutterbar of the harvester and the 6 m nominal width of the cultivators and drill. Although this difference can be catered for during the harvesting operation (see detailed operating plans below), it leads to an inefficient use of the harvester, which is unacceptable, other than perhaps on a trial area. With this particular range of equipment a gradual change may therefore be necessary. The aim within the machinery replacement policy would be to get everything up to around 9 m, or to strike a compromise and match all equipment at 8 m. The positive aspect of this change, particularly to 8 m, is that due to the lower draught demand of both the cultivators and drill within a CTF regime, it is unlikely that larger tractors will be required. However, some skill will be needed during the transition period to avoid having a wider cultivator and drill, but no CT land upon which to work them! This is where the trial area comes in. To set this up, the following procedure is suggested: Wheelways at 6 m centres will be set up during harvesting of the first wheat. This operation will use the existing 24 m tramlines as both a starting point and as a means of reducing cumulative errors. Two pairs of marker lines will be established on the reel of the harvester. While working within the tramlines, the first pair of marker lines, set at 990 mm from the reel centre (based on a tramline wheel track width of between 1.9 and 2.0 m), will be used to help keep the vehicle on the tramline centre. In the spaces intermediate between the tramlines, one of the second pair of marker lines (at 1.42 m from the reel centre) will be placed along the crop cut edge and will help the driver achieve the 6 m module width required. On reaching the next tramline, the driver will revert to the other markers to centre on the tramline. Unloading grain to the chaser is anticipated on the headlands, but if the dimensions of the equipment are appropriate, it may be possible to do this on the move.

Despite the spreading of straw behind the combine, it is anticipated that the wheel marks produced by the combine will be identifiable for the next operation. This will involve one-pass cultivation with the 6 m Simba Series 2 discs. These should be set to provide adequate tilth for sowing within the combine wheel tracks, and sufficiently deep to fill but not obliterate the old tramlines. The latter (marked if necessary) will then be used as a starting point for the drilling operation with the Simba Freeflow. After 4 successive bouts, a check should be made to ensure that the operation is still centred on the next old tramline. If it is not, a correction should be applied and the drill marker adjusted if necessary. The aim will be to establish the new tramlines in the same position as the old ones.

Figure 8

Calculations based on wheel and track settings shown above suggest that the system will provide a maximum uninterrupted non-trafficked width of 2.2 m. This will occur between the outer extremities of the combine wheels on successive passes.