Many thousands of hectares of semi leafless field peas are harvested trouble free each year as new Kaspa type varieties together with grower experience and recent machinery innovations and modifications, have solved the majority of harvesting difficulties.
Semi-leafless Kaspa type field pea varieties like PBA Gunyah, Twilight and Wharton have a substantially improved structure for harvesting compared with the old trailing types such as Dunwa or Parafield. In most conditions the Kaspa types will stand better at harvest than trailing type varieties.
Nevertheless, for ease of harvest, particularly in circumstances where semi-leafless peas may lodge, it is important to prepare paddocks prior to, and after sowing to ensure a clean level paddock for harvest. Some semi-leafless peas including PBA Gunyah, Twilight and Wharton have a sugar pod trait that reduces pod shatter.
The combination of reduced lodging, improved pod height and reduced pod shatter available in semi-leafless lines like PBA Gunyah, Twilight and Wharton results in lower losses in the paddock and a cleaner sample. In Kaspa type field peas like cereals may be harvested above ground level, even where it has lodged.
This is because most pods are formed near the top of the plant. Even the most efficient harvesters cannot overcome poor planning. Successful field pea harvesting begins at the end of the previous season through good paddock selection and stubble handling. Decisions made at sowing and spraying of the field pea crop are also important.
Probably the most important step in reducing harvesting difficulties is to select a paddock with a low weed burden, particularly broad-leaved weeds and which is relatively even and free of stones, sticks and large soil clods. Broadleaf weeds such as wild radish and mustard decrease yield by competition and increase harvest losses.
Rolling, which levels the paddock and pushes small rocks and sticks into the soil is the second most important step. See Levelling the paddock. The moisture receival standard for field peas is 14.0%. The crop can be safely harvested at 16% moisture and if left in a stack the seed will dry out naturally. Harvesting at 14-16% moisture will have no effect on seed viability and the grain will be less prone to mechanical damage during handling.
Field peas can lose seed moisture rapidly and will be more prone to damage below 12% moisture. Therefore do not delay the harvest of seed crops any longer than necessary. Semi-leafless field pea varieties which have the ‘sugar pod’ trait have been found to be best harvested in warm conditions. In cool damp weather the vine can be hard to thresh and choppers and spreader efficiency is reduced.
Harvester settings will depend on crop foliage and seed moisture, but the following table and the header operator's manual may be a useful starting guide.
|Reel Speed||1.1 X ground speed|
|Table auger clearance||7-12mm|
|Drum or rotor speed||300-600rpm|
|Concave clearance||10-25mm (start at 10mm)|
|Fan speed||60-75% (start at 75%)|
|Top sieve||20-25mm (start at 25mm)|
|Bottom sieve||10-15mm (start at 15mm)|
Drum or rotor speed should be kept to a minimum without significantly reducing the harvesting capacity. As a guide, to reduce pulse seed damage the peripheral speed of the drum should not be greater than 12 metres per second (20-30 metres per second for cereals). Harvesters have a range of drum or rotor diameters so this will have to be checked in order to start at around the correct rotational speed.
|Make||Model||Drum or rotor diameter (mm)||Drum or rotor speed for 12mps (rpm)|
Grain handling and storage
Once field peas are harvested they should be handled as few times, and as gently, as possible. This is because they are very fragile, and the mechanical damage caused by augering, for example, can reduce germination percentage.