Vetches are winter-growing legumes
Paddock selection
- No more than one common vetch crop in the past three years
- No more than one faba bean or narbon bean crop in the past two years
These species harbour the same botrytis fungus that causes chocolate spot in vetch.
- At least 500m away form last years vetch, faba bean, narbon bean, chick pea or lentil crop
- Free from sulphonylurea residues
Ensure that at least two years has passed since sulphonylurea herbicides (Glean, Ally, Logran) were applied in the paddock. Common Vetch is sensitive to sulphonylurea herbicides and will be damaged if residues of these herbicides remain in the soil. These herbicides will break down within one to two years of application depending on soil pH, organic matter content, soil structure, and rainfall. Minimum plant back periods must be observed.
- Medium to heavy textured soils (pH above 5.5)
Common vetch will grow well on a wide range of soils, similar to field pea. Nodulation and plant growth will be best in neutral to alkaline soils (pH 6.0 to 8.0), but successful crops are often grown on soil with pH values ranging from 5.0-9.0 (CaCl2). Highest yields have been obtained on well-drained clay-loam soils but Common Vetch can be grown very successfully on soil types ranging from shallow duplex (10cm of sand over clay) to heavy clays. They perform consistently better than chickpeas and lentils on alkaline mallee soils and tolerate the elevated boron levels found in Western Australia mallee soils(Boron>5 ppm).
- Low number of broadleaf weeds
- For efficient harvesting the paddock should be relatively even and free from sticks or stones
Other considerations
Common vetch is difficult to control in lentil crops and seeds are of similar size and appearance, and are very difficult to grade out. There is a nil tolerance of common vetch in lentil grain, so lentil should not be grown in close rotation with common vetch.
Vetches are increasingly being used as a green manure crop, and in some instances common vetch is manured in September prior to a summer crop being sown. Careful consideration should be given to the chemicals used in the common vetch crop to ensure they are not harmful to the summer crop (eg. Spinnaker).
Common vetch does not tolerate waterlogging. Preliminary studies indicate that narrow leafed lupin tolerates a higher incidence and duration of waterlogging than vetch when grown on sandy duplex soils. On heavier soil types reports are mixed, with many growers noting common vetch appears to recover better than field peas from a short duration (7-10 days) of waterlogging during the vegetative growth phase.
Vetch
Soil type
Suitable soils within the Northern Agricultural Region include:
- heavy red cracking loams and clays such as the local soil names in the Mullewa, Morawa and
Mingenew districts; red brown loams over a clay subsoils such as the heavier Salmon
gum-Gimlet and York gum-Jam soils - grey clays and hard setting clay loam soils. Moort soils are suitable provided they meet theconditions listed above in??
- Kumarl, Dowak and Shallow Circle valley soils in the in the Salmon Gums area and Scaddanloams and shallow duplex soils in the medium rainfall mallee
Sowing date
Experiments conducted in 1997-99 throughout the low and medium rainfall zones of southern Western Australia indicates the best time to sow Langeduedoc vetch is May, and in most areas the second half of May produces the highest yields. Delayed sowing until June reduces yield and dry matter production by as much as 40% in low rainfall regions. In medium and high rainfall zones the effect on grain yield of delayed sowing until June will be less marked and yields of 1.1 t/ha can still be achieved. The majority of experiments conducted in Western Australia have used the early flowering variety Languedoc. The varieties Blanchfleur and Morava are later flowering than Languedoc and may suffer greater yield loss from delayed sowing.
Optimum sowing time is a compromise between sowing early to provide adequate time for vegetative and reproductive growth, and sowing later to avoid frost and manage disease and weeds. Sowing common vetch in April has produced lower yields because of poor crop establishment and disease, and it increases the dependence on pre-emergent herbicides.
There is also the additional consideration of fitting in with other crops (cereal or canola) that may have priority in the seeding program.
Inoculation
Always inoculate common vetch seed with Group E inoculum. This applies regardless of the cropping history of the paddock. In situations favourable to the persistence of rhizobium in the soil, crops may nodulate without inoculation. Experience has shown, however, that often a less efficient rhizobial strain has nodulate the crop and nitrogen fixation is low. Therefore inoculation is recommended in all circumstances.
Inoculated seed must be sown within 24 hours of applying the inoculum. If more than 24 hours elapses, then reinoculate seed at the same rate recommended on the packet. The survival rate of rhizobium on inoculated seed (not dressed) that is sown into dry soil is lower than if it is sown into moist soil. The rate of inoculum for dry sowing, therefore, should also be increased in order to improve the chances of the rhizobium survival.
Fungicide seed dressings are toxic to rhizobia. If the seed has been dressed, then double the rate of inoculum and sow seeds as soon as possible after inoculating into moist soil. The rhizobium will quickly die if it is applied to fungicide-dressed seed and then sown into dry soil. It is important to take care when inoculating seed. There are many cases where poor inoculation technique has caused crop failure. Peat sprinkled out of the bag onto seed as it is being augured into the seeder is quick but not effective. Slurry inoculation is the best way to ensure a well nodulated crop.
