6. Returns sample

Combine returns

A good starting point in cereal crops is to aim for a 5mm difference between top and bottom sieve openings. This is the key to getting the returns sample right. It should be a good mix of unthreshed ears and trash with hardly any clean grain

Check the volume of material at the top of the returns auger. If it is more than half full of trash then the top sieve needs closing.

If there is clean grain in the returns then the bottom sieve needs to be opened up.

Closing the sieves down narrows the channel of air from the fan, increasing the actual air-pressure and thus boosting cleaning ability. In effect, closing the sieves has the same effect as increasing fan speed.

1.Grain tank sample

2. Crop flow

3. Drum and concave

4.Grain pan

5. Sieves

7. Straw walkers

Top tips to boost combine harvester output