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Preparation is key to happy harvesting

May 2021

Jenny Mathews, Pula Imvula contributor. Send an email to jennymathews@grainsa.co.za  

Farmers want to harvest and sell every kernel they produce. Proper maintenance and adjustments during harvest time are critical in achieving this. Preventative maintenance is an ongoing and regular care plan which is executed by farm owners or the farm workers.

Most of the summer grain growing regions have seen an abundance of wet weather during the season, and for a change most farmers are looking forward to an abundant harvest time. We were doing some calculations recently; and realised that our tractors, trailers, combine harvesters, de-bulking equipment and threshing machines are going to work harder than they have in a very long time. They will likely cover many kilometres and carry countless heavy loads.

We need to be extra certain that the machines can cope and get our crop safely to the market place, because any downtime during the harvesting processes will end up being very costly.

Jurie Mentz made this farmer stop the harvester to check the beaters as too much grain was filtering through. Guidance is one of the advantages of the Farmer Development Programme.


  • Reducing the likelihood of equipment failure.
  • Avoiding unexpected equipment breakdowns.
  • Extending the lifecycle of equipment.
  • Maximising on the equipment’s value.
  • Saving time by planning and scheduling ahead.

Grain producers are fine-tuning their equipment now to reduce mechanical delays, improve performance, assure a safe harvest and maintain grain quality once they start combining the crop.

A few hours spent with combines, augers/conveyors, dryers and storage bins will usually have a considerable payback in the form of time saved and reduced deductions at the point of sale. All equipment that will come in contact with the grain, as it moves from the field to the storage bins or silos, should be thoroughly cleaned prior to harvesting to minimise mould and insect infestations, and to protect the purity of individual corn varieties or seed lots. Combines, hauling vehicles, conveyors, drying equipment and storage bins should be thoroughly cleaned before the rush of harvesting begins.

If you plan on storing your own grain, then thoroughly clean out all grain bins, especially caked grain that will contaminate the new crop. Sweep down walls, ladders, ledges and floors inside grain bins to remove old grain and fine material, where insects and mould spores can be waiting to invade the incoming crop.

Harvesting at Driefontein in the Donkerhoek-area. (Photo taken in 2017).

Harvesting using a mechanical threshing machine.


Assuming the combines were thoroughly serviced and cleaned after last season’s harvest, the following problems should have been addressed already:

  • Bearings: Were they too loose or worn? Were they checked and replaced where necessary?
  • Wheel bearings: Grease.
  • Fan belts: Replace worn or stretched fan belts.
  • Chains: Replace stretched out and worn chains.
  • ‘Pensketting’: Check the intake chain.
  • Tyres: Did any of the tyres cause problems with frequent punctures? Replace worn tyres.
  • Bushes: Check the wearing bushes and replace. The condition of the ‘shaker bushes’ is important.
  • Elevators: Check for tension on elevator chains.
  • Sieves: Look for leaking or damaged sieves, as your grain will leak or your sample will be dirty and compromised, lowering yields and grades.
  • Inspect your rotor and concaves, as this part turns and is the most critical part since it is where the grain is removed from the cob.
  • In the Slattery combine harvesters, check that the beater bars are not too worn and that they are adjusted correctly. They can either not remove all the grain off the cobs or, if set too aggressively, they can break the pips. Also, check for damage on the sieves.

All these issues need to be check-listed before the harvest begins. Pre-harvest check and grease all bearings once again. All this applies to small and larger threshing machines and combine harvesters. If you have a self-propelled combine, perform a complete service including oil change and filters replaced. 

Harvesting with slattery.

De-bulking trailers
Check the following:

  • Chains, elevators and augers for wear and tear. Do the bearings need replacing? Do the chains need to be tightened or replaced?
  • Areas that are rusty will cause the grain to leak out.
  • Tyres need to be in good condition.

For transporting the crop
Check the following:

  • The draw bar at the front of the vehicle. Are there any cracks that need welding?
  • Worn pins or bushes. Replace them if necessary.
  • Grease the ‘skamel’ (swivel) to ensure there is no wear.
  • All tyres for wear and tear, as well as the rims for cracks. Repair or replace if necessary.
  • Grease all wheel bearings.
  • The bulk sides to ensure there are no gaps or leaks.
  • The side flaps that open to release the grain must work smoothly and be secure, so they don’t open accidentally in transit.
  • If you are driving on public roads, are your licences in order? 

Publication: May 2021

Section: Pula/Imvula