Sowing rate and depth
Sow sufficient seed to establish 45 plants/m for conventional-leaved varieties and 55 plants/m for semi-leafless varieties. The necessary sowing rate will depend on germination percentage and seed size.
| Variety | Thousand seed weight (g) | Germination % | Sowing rate (kg/ha) to get 45 plants/m2 | Sowing rate (kg/ha) to get 55 plants/m2 |
|---|---|---|---|---|
| PBA Twilight and PBA Gunyah | 185 | 80 | 104 | 127 |
| PBA Wharton and Kaspa | 220 | 80 | 123 | 151 |
At these sowing rates yield is usually fairly unresponsive to changes in density. However, dense crops compete better with weeds and feed better when harvesting, so resist the temptation to reduce sowing rates.
Field peas grow well in conventionally spaced rows (18-25 centimetres (cm)). Limited research in the 1990s showed no adverse effects on yield of planting in rows as wide as 36cm, but poorer standing ability (with a conventional-leaved prostrate cultivar) was observed, and consequently more difficulty harvesting.
For this reason, wider rows are not recommended for field peas. Standing ability in semi-leafless cultivars is likely to be impaired in wide rows too, since plants will experience less support from their neighbours than in narrow rows.
Levelling the paddock
Trouble-free harvesting requires an even soil surface and this is best achieved by rolling. This is most important for prostrate cultivars, but applies also to semi-erect cultivars because these will lodge under some circumstances.
Use either steel or rubber-tyred rollers. Heavy steel rollers do a better job leveling heavier soil types, especially the larger ridges left by no-till seeding, and pushing small stones and sticks into the ground. However, they have a greater tendency than rubber-tyred rollers to smear and seal the soil surface if it is moist.
It may be necessary to wait for the soil surface to dry after seeding before rolling with a steel roller where a rubber-tyred roller could follow directly behind the seeder. Less pressure is required to knock down ridges on sandy soils and on them rubber-tyred rollers are just as effective as steel rollers.
Roll is best done straight after sowing, as long as the soil surface is not too moist. However, field peas can be rolled after emergence, when it is best between the three and 10 node stages.
Rolling earlier risks damaging emerging seedlings and older plants are usually too tall to recover completely from being knocked down in the rolling operation. Don't roll for two weeks before or after applying post-emergent herbicides, as the stress of rolling will predispose the crop to damage from these herbicides. Rolling emerged crops is best done in the afternoon, as then the plants are more flexible and less likely to be damaged.