Seed harvesting, processing and cleaning of serradella

Page last updated: Monday, 17 October 2022 - 12:07pm

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Cultivars of French serradella (Eliza, Cadiz, Erica and Margurita) and yellow serradella (Charano, Santorini and Yelbini) have been developed with the aim of reducing the cost of seed production. Most of these varieties grow relatively upright when ungrazed and have good pod retention at senescence, allowing them to be more easily harvested using conventional grain harvesting machinery. For the hardseeded cultivars further processing is necessary to enhance germination.

When to harvest

Serradella pods can be collected using a standard grain harvester as soon as the majority of the vines are dry and brittle. In some situations the crowns and lower parts of the vines may still have a little greenness but this does not usually affect harvesting. If left too long, the pods will begin to shed, but if harvested too early the green vines will tangle and block the header front. A high moisture level can also reduce the efficiency of the dehulling process for yellow serradella. Check to make sure that at least 90% of pods are dry before starting harvest. Vacuum suction harvesting may be necessary for short or sparse pastures.

Desiccating broad-leaved weeds

You may need to desiccate wild radish, wild turnip and other green broad-leaved weeds before harvest by applying diquat (such as Reglone®), plus wetter, 4-7 days before harvest. Green radish and turnip may cause blockages to the harvester and radish has affected the germination rates of other stored seed. The spray application also desiccates any green serradella but can also significantly affect seed viability if the chemical is applied too early. This technique can be useful to even up a stand that has varying levels of greenness.

Harvesting French serradella

One of the important qualities of French serradella is that it grows erect and holds onto its pods for a few weeks after maturity, providing the opportunity for the seed to be collected easily and at low cost using a standard grain harvester. Only a few minor adjustments are required if the harvester is already set up for harvesting wheat. During the harvesting process pods break up into individual segments with one seed inside each segment. Eliza and Cadiz are about 99% germinable when harvested and is sold in pod form. This means the seed does not need to be removed from pod segments and scarified to improve germination.

Erica and Margurita, on the other hand, are hard seeded cultivars and will have less than 10% germination at harvest. These cultivars do need to be dehulled and scarified to increase germination rates to a level suitable for new sowings. However, the dehulling process is easier and more efficient than with yellow serradella. Harvest yields for French serradella are generally in the range of 300-700 kilograms per hectare of cleaned pod with some reports of up to two tonnes per hectare. Pod of the hard seeded french serradella cultivars are 65% seed.

Best harvesting results

Use a conventional (standard or rotary drum) open-front grain harvester, with a finger tyne reel. The machine settings are similar to those for wheat, except the drum speed should be at a minimum and air strength reduced to about half. When the drum is set correctly the pods should break up into individual segments. If the pods are not broken into single segments the drum speed should be increased. If there is naked seed in the harvested sample then the threshing is too aggressive and drum speed should be reduced and/or the concave gap increased.

The air strength should be set at a level where some pod is blown out the back of the harvester. This removes empty and light pods as well as light weed seeds such as silver grass and capeweed and ensures a clean harvest sample. It is better to sacrifice some pod out the back of the harvester rather than pay extra cleaning costs. We recommend that crop lifters should be fitted to the platform every 30cm. Short season upright crops may be successfully harvested without crop lifters, but thick and lodged crops can be difficult to harvest without them.

French serradella harvest checklist

  • Desiccate green weeds before harvest.
  • Finger-reel open fronts work best.
  • Crop lifters are recommended, fitted 30cm apart.
  • Harvest in warm to hot weather conditions.
  • Standard harvester drum speed 600-900 revolutions per minute (rpm).
  • Rotary harvester drum speed 700-1100rpm.
  • Concave gap as for wheat.
  • Slow wind speed to 600-800rpm.
  • Open top sieve same as for lupins.
  • Set bottom sieve same as for wheat.
  • Use trial and error to obtain a good clean sample.
  • Seed of Erica and Margurita needs to be dehulled and scarified to increase germination.

Handling the seed

French serradella pods auger easily and can be stored in grain bags, bulk-a-bags or in grain silos. If weeds are present then you can store it on the farm in bulk and then take the sample to seed cleaning businesses during January and February when most other grain cleaning has finished.

French serradella seed and pod
French serradella seed and pod

Cleaning the sample

Seed should be cleaned of weeds before use on farm or for dehulling in the case of Erica and Margurita. If using a commercial seed cleaning service, ensure they have the right cleaning apparatus and preferably are experienced in cleaning serradella. Some farmers have successfully used mobile seed cleaning machinery. If you have your own seed cleaning equipment, try using a slotted screen that allows the pod segments to pass through the slots but separates the larger weed seeds. Then put it through again using a smaller screen to remove all the small seeds and retain the clean pod.

Contact information

+61 (0)8 9368 3907