Most farmers on the lookout for a good quality second-hand fertiliser spreader will be looking for a twin-disc spreader. These are now the most common spreaders on the market.
You want to be able to spot a machine that, while it may not be new, has at least clearly been looked after and isn't rusting. As outlined above, you want to buy a machine that comes with a calibration kit, so ask this question at the outset.
When you know where to look, it doesn't take long to form an impression of how well or otherwise a used spreader has been looked after.
Too much rust is always bad. If an older spreader has been maintained correctly, it should still look reasonably well. The discs should be firm to feel with little play. A clearly loose disc with too much play suggests bearing trouble.
The spreading vanes should be clean and the hopper shouldn't be corroded. The vanes are the hardest working parts on the spreader and when they become worn, they get small indentations, similar to what a crumpled piece of paper looks like. This happens over time as the fertiliser prills wear down the metal.
If vanes are nearing the end of their life, you should factor in that the cost of replacing them will be €350-€450. Can this be negotiated off the sale price? Ask to see the spreader working - this is the acid test for the spreader gearbox and will rule out any obvious defects.
Look at the condition of the pto shaft and check that the shaft guard is in good order.
Similarly, check the hydraulic hoses for leaks or cracks. The hopper body and the A-frame for attaching the spreader should be smooth and free of cracks.
Finally, the hopper cover is usually well kept in a machine that has been cared for and stored well over winter.
This cover serves to keep the fertiliser dry and clean, so a damaged cover will lead to costly losses.
1) Safety first: ensure the spreader has an intact PTO shaft cover in place.
2) Correct spreader settings are machine specific and are based on the type of fertiliser being spread and the bout width chosen. Basic information is given in your spreader's instruction manual. If you don't have these, spreader manufacturer websites and phone apps are also a great source for up-to-date settings.
3) As a rule of thumb, the spreading discs should be slightly higher on the back than on the front in order to give the granules the required trajectory when they leave the spreading vanes. Lift controls should be set to allow correct disc height (as determined by the manufacturer and fertiliser type) from the crop or ground.
4) Tighten the lift-arm stabilisers to prevent the spreader jolting on rough ground. Make sure both lift arms are level to minimise bias.
5) Once your forward speed is set, it is essential to maintain the same forward speed all the time, e.g. 7km/hr. The same applies for PTO speed - this should not be altered once spreading begins.
6) Headlands can be awkward and potential areas of over application, so shut off the spreader once the back wheels of the tractor meet the inside track of the headland run. This prevents covering an area already spread. GPS-based switching can automate this process and improve accuracy on wide spreading machines.
7) Borders with water courses and field boundaries also pose a challenge. Manufacturers offer a range of mechanisms to help. These include: tilting the spreader down at the boundary side; changing disc speed; adding a deflector; reversing disc direction or changing the granule drop point to use a different disc vane.
8) Only buy quality fertiliser that has good spreading characteristics with at least 80pc of the granules in the 2mm-4mm size range, and preferably granules of smooth round shapes. This will ensure a good even spread pattern. Rounded granules roll off the discs more predictably than irregular granules.
9) Clean the spreader after every working day to protect it from corrosion and lubricate working parts.
10) Check the spreading vanes for wear, pitting or indentations. Vanes on a 12m spreader typically last three to four seasons, an 18m spreader, two to three seasons, and a 24m spreader, two seasons. A new set of vanes cost from €350-€450.