Seed rate and depth
Seed Depth
Sow common vetch between 5-8 cm deep. Sowing deeper than this can reduce emergence, particularly if the soil is susceptible to surface crusting. Placing seed less than 5 cm deep increases the risk that herbicide applied immediately after sowing will come in contact with the seed or developing roots. This risk is greater in sandy surfaced soils. There is also some evidence that shallow sowing makes plants more susceptible to insect and disease attack.
Common vetch can be dry sown if:
- the broad-leaf weed burden is low
- the seeding rate is increased by 10 percent and the recommended rate of rhizobium is doubled; the seed has not been dressed with a fungicide
- the soil is not hard setting or sodic
Emergence of dry sown crops will be staggered and patchy, particularly on soils prone to non-wetting,and weeds are likely to be more difficult to control.
Sowing Rate
In areas where grain yield is expected to be above 1.5 t/ha a target density of 60 plants/m2 is recommended. In all other areas 40-plants/ m2 is adequate, but there is no yield penalty in aiming for a higher density.
Establishing an even, healthy crop is the key to achieving consistently good seed yields of vetch. Low-density crops (25 plants/m2 or less) complete poorly with weeds, are more attractive to aphids and are more difficult to harvest.
The seed rate require to achieve this density depends on seed size, germination percentage and field establishment. Only about 60-75 percent of the seeds sown establishes in the field, depending on the conditions at sowing. Morava has larger seed than Languedoc or Blanchfluer and therefore normally requires a higher seeding rate.
Nutrition
Fertiliser
Fertiliser requirement is similar to other pulses. In most situations a maintenance application of 70-150 kg /ha superphosphate is all that is required. Starter dose of 10-12 kg nitrogen/ha at seeding (preferably away from seed) may be useful if soil pH is less than 6 in CaCl2 or the soil has a low nitrogen status.
Harvesting
Direct heading
Common vetch is ready to harvest when the pods are light brown and the seed rattle within the pods when shaken. Pods can be shed and shatter if harvesting is delayed. Common vetch sown in May will mature in mid-late October.
Languedoc will mature at or before Dundale field peas. Blanchefleur and Morava will be ready to harvest 10-14 days after Languedoc. Grain should be delivered with 14 percent moisture content. Crops have been successfully harvested with moisture contents of 13-16 percent. If grain at 16% moisture is left in a stack will naturally dry out. This will reduce yield loss at harvest and may improve the seed size and colour.
Common vetch is best harvested with crop lifters and finger tine reels, across the lay of the crop. The lifters should be spaced so as to fit the shortest length of the vine to be harvested. Normally this is 300 mm. A lifter should ride on its flat section behind the tip, not on the point, to avoid damaging the lifter and soil being thrown into the front.
Most harvester fronts can be tilted, so once lifters are fitted, the harvester front angle should be adjusted. The lifters should have adequate travel for the conditions. The finger tine reel or pick-up reel should be set forward and lower than the knife to reach down and gently lift the crop over the knife. The finger angle is adjustable and should be set perpendicular to the top edge of the lifters. The ideal option is to link reel speed to ground speed.
Pea plucker fronts can be used, but because common vetch is more firmly anchored to the soil than field pea, excessive soil may be thrown into the harvester. Screens on the clean grain and repeat elevators may help remove soil from the grain. If the crop is not harvested or swathed on time and continues to lodge, a plucker may be the only way of harvesting the crop.
Common Vetch may be swathed when the top pods are still green and the bottom 75 percent of pods are yellow-brown and the seed just hardening. This is the same timing as for croptopping or desiccation. Grower experience in the Esperance region in 1998 and 1999 was that the swath was quite stable in most wind conditions. To further reduce the risk of the wind moving the rows the swath may be rolled.
Floating flexible cutter bars or flexi-fronts are ideal as the knife can follow the ground contour and stay very close to the ground without extreme driver concentration as required with conventional fronts.
Forage and Hay
Once established, common vetch can be grazed. Depending on intended end use it is best to let common vetch grow to a height of 10-15cm before grazing, and then only graze to within 3-5 cm of the ground. Remove sheep at or near flowering.
Common vetch produced for hay should be cut a few weeks after the start of flowering.
Mixing oats and common vetch seed and sowing them at the same time can produce oat-vetch hay. Use 15-25 kg/ha of common vetch and 30-60 kg/ha oat seed. Horses prefer a higher proportion of oats in the mix, while ruminants prefer a greater legume component. Oat-vetch mixes will respond to nitrogen up to rates of 30 kg nitrogen/ha. Use high rates of nitrogen when the proportion of vetch is reduced.
Green Manure
The best time to green manure vetch is often a compromise between achieving maximum biomass and nitrogen production of vetch and killing resistant ryegrass at the most effective time. Most farmers aim for maximum effect on ryegrass. Common vetch can be quite hard to kill at the late flowering-early pod set stage. Often glyphosate alone will not kill the crop. Experience has shown that Lontrel(50-300 mL/ha) added to high rates of glyphosate (1-2 L/ha) effectively hastens the kill. However in some situations it may still be necessary respray or graze the crop to kill regrowth.
Grain Handling and Storage
Common vetch seed can be easily damaged. Most visible damage is when the grain is split but less obvious damage can occur to the seed coat which will reduce the germination rate. Seed sold for cover crops in orchards must have a germination percentage of 95 percent. To minimise damage the following steps should be adopted:
- Keep handling to a minimum
- Use grain belt conveyors rather than augers if possible
- Augers if used should be run slowly and full
- Avoid handling the seeds when very dry or brittle
- Avoid dropping seed from heights
In Western Australia the seed of common vetch is easily stored in any rainproof enclosure, shed or silo.
Quality standards
The minimum receival standard for farmer dressed common vetch is 97 percent purity by weight with a maximum moisture content of 14 percent and a maximum of 5 percent defective seeds. Specific up to date standards for common vetch receival and export are available on the Pulse Australia website. Visit: www.pulseaus.com.au
