Namoi woolly pod vetch (Vicia villosa ssp. dasycarpa cv. Namoi) is a self-regenerating legume that was originally introduced from Turkey in 1951. It was further developed at the University of Sydney’s Plant Breeding Institute at Narrabri into a useful and adaptable legume that can be grown throughout the state. It is an annual which grows from autumn to spring, and does well on many soil types and in varying climates.
Namoi woolly pod vetch (NWPV) has been used on the North-West Slopes and in central and southern NSW as a pioneer species when developing new country. It is also very useful when rehabilitating old cultivation areas. NWPV is often sown with winter cereal fodder crops to increase protein levels in the fodder.
This cultivar is sprawling and weak-stemmed, with purple, pea-like flowers. It will grow through and over associated plants to produce a dense, intertwined sward as shown in the photo on the right.
The plant flowers profusely from late spring to early summer, producing many two-seeded to five-seeded pods. The seeds are:
Early growth, particularly from winter sowings, is very slow. The young, almost fernlike, prostrate runners are weak and easily damaged by grazing.
NWPV is adapted to a wide range of soils varying from heavy basalts to granites, but the soil must be at least moderately fertile for satisfactory production. NWPV responds well to added phosphorus and sulfur in fertilisers when soils are low to moderate in fertility.
Woolly pod vetch does best on well-drained soils and will not tolerate waterlogging. It does not perform at high levels of exchangeable aluminium in the soil, having a similar tolerance to that of sub clover and white clover, but less than that of serradella.
Namoi woolly pod vetch will grow successfully in areas receiving at least:
It has an intermediate flowering habit and, with moderate temperatures and adequate moisture, will grow on into the summer months.
Its substantial root system and its ability to flower quickly and set seed in a dry spring give it good drought tolerance. This cultivar has enough hard seed to ensure survival, providing it is allowed to seed every few years.
Low temperatures restrict growth of NWPV during winter, while spring growth is rapid. Although grown successfully in many tablelands areas, it is unsuited to the cold, high, elevated areas such as the Monaro in the south and the high-altitude tablelands in the north. In these areas it is less productive than white clover and sub clover and is not recommended as a pasture species here.
NWPV can be:
Surface-sown vetch does better when litter is present on the soil. It does not establish satisfactorily from surface sowing on bare or hardsetting soils. Sow at that period of the year when soil moisture is increasing and there is the greatest probability of follow-up rain.
Although it has a large seed, the vetch seedling is weak and fragile and may not survive if seed is sown in heavy soils at depths greater than 3 cm. On light, friable soils, seed can be sown slightly deeper.
The long growing season of NWPV allows sowing to be spread from February to mid-June. Early sowing is recommended to establish the seedlings before cold conditions restrict growth, which can be very slow when seed is sown late. February sowings have been successful at the higher altitudes, but lower slopes areas can be too hot at this time and May is often the preferred sowing month here.
A sowing rate of 6–10 kg/ha should give a good seed set in the first year. In pasture mixes, a rate of 4–6 kg/ha is suggested. Heavy seeding rates are necessary because of the large seed size.
If sowing with a combine, use a similar setting to that used when sowing wheat, and sow through the fine side of the seedbox.
Whatever sowing method is used, seed must be inoculated with the correct strain of rhizobium (Group E). For best results, use seed of known and tested quality.
The application of phosphorus, sulfur and molybdenum may be required to successfully establish vetch and promote vigorous growth. Soil tests are a guide to phosphorus requirements and will also give an indication of sulfur deficiency, as soils high in phosphorus will often respond to sulfur. Soils with a low pH are often deficient in molybdenum.
On acid soils with a pH(CaCl2) of less than 5.0, adding lime will aid establishment and growth of NWPV.
Careful grazing management is critical for successful production from NWPV. It is a slow winter grower, especially in the colder tablelands areas, and regrowth can be poor if it is grazed before branching occurs. However, it recovers vigorously if grazed after branching and before growth becomes tall and rank. Grazing young seedlings can kill the plant.
As cattle tend to avoid young plants, light grazing of mixed pastures by cattle should result in little damage. When attempting to build up a seed reserve, allow stock to graze only lightly from flowering onwards.
It is most important to ensure a heavy seed set in the first year. If a substantial seed bank is built up in the first year, the plant can regenerate in later years from residual hard seed, even during successive years of drought in which little new seed is formed.
Vetch is more persistent where cattle rather than sheep are grazing. It is also more persistent under extensive or large-area grazing systems rather than under intensive systems with high stocking rates.
A threefold increase in carrying capacity was recorded on non-arable, basalt soils at Inverell in NSW when NWPV was introduced into natural pasture with adequate fertiliser. In addition to the increased carrying capacity, the improved pasture can change the enterprise from store production to a fattening operation.
NWPV is high in protein and has a high digestibility level. Chemical analyses of samples taken from Gilgandra and Canberra in the spring have shown protein ratings of 19.5% and 25.88% respectively, which is comparable to clover and other legume pastures.
For livestock, especially cattle, this legume initially has a low palatability, and it may take a few days before vetch is readily eaten. For this reason it is only suitable for grazing by dairy cows when it is part of a mixed pasture. The cows will eat other species at first but gradually come to accept the vetch.
On the Northern Slopes, NWPV has produced much greater growth increases than those obtained with naturalised annual legumes. Elsewhere it has produced useful forage as a pioneer legume, increasing animal production from the area and building up soil fertility. In many tablelands areas, however, white clover and red clover produce better results as pioneer legumes.
NWPV is far less likely than many other legumes to cause bloat in cattle.
Naturally hayed-off growth, and hay made from NWPV, can be highly nutritious and attractive to stock. Because of its long, twining stems (up to 2 m), it is difficult to form into conventional windrows by raking, but a slasher/windrower can be used instead.
NWPV is tolerant of many pests and diseases and is resistant to:
The only pests to cause it much harm are:
Your local district agronomist can give advice on control.
Damage caused by the fungus botrytis has been recorded in the Southern Tablelands and North-West Slopes following very wet weather.
If growing NWPV for seed, sow at a rate of 6–10 kg/ha of scarified seed. Scarifying reduces the percentage of hard seed and increases germination in the first year.
Pre-emergent chemicals are available for the control of grasses and some broadleaf weeds. There is no satisfactory broadleaf control chemical for post-emergent weed control in vetch.
ALWAYS READ THE LABEL
Users of agricultural (or veterinary) chemical products must always read the label and any Permit before using the product, and strictly comply with the directions on the label and the conditions of any Permit. Users are not absolved from compliance with the directions on the label or the conditions of the Permit by reason of any statement made or not made in this publication.
Seed crops should be grazed only lightly during autumn and winter. Remove stock when flowers appear.
The crop can be harvested for seed by conventional open-front headers with crop-lifters, but seed is likely to shatter if harvesting is delayed. Harvest the seed as soon as the plants, pods and seeds are dry enough to thresh.
Harvesting can be made easier if the seed crop is sown with 10–15 kg oat seed/ha. The oat seed is readily graded out of sample and the oat plant provides a framework for the twining, usually prostrate, vetch. This increases harvestable yield.
Seed yields of up to 750 kg/ha have been recorded, but most commercial seed crops yield between 150 and 300 kg/ha. Difficulty in harvesting and heliothis damage are the main reasons for the lower yields.
NWPV has high levels of hard seed and it may infest crops of wheat and barley that follow. During the growing period, the vetch competes with the crop and will smother it and make harvesting difficult. It is important to be aware of this problem when planning rotations.
Poisoning of stock on vetch has been reported. However, such reports are rare and the poisoning has always been associated with cattle grazing on vetch-dominant pastures.
The available commercial varieties of woolly pod vetch are:
Haymaker Plus † is claimed to be earlier flowering than Namoi, with better winter growth but a similar level of hard seed (about 80%). It has been selected for its ability to produce large amounts of dry matter.
Capello † is a soft-seeded alternative to Namoi, with about 80%–90% soft seeds making it more suitable for a short-term cropping rotation. The low percentage of hard seed will greatly reduce the possibility of volunteer plants causing weed problems several years after vetch has been used in the rotation.
Note: † Denotes that this variety is protected by Plant Breeder’s Rights.
A number of other species of vetch are sometimes used for grazing.