Onobrychis viciifolia Scop.
Sainfoin, St Foin, holy grass
Author:Dr John Frame
Pubescent perennial with many erect or sub-erect, hollow stems , 60–80 cm or more, arising from basal buds on a branched root stock. After defoliation , branches develop from axillary buds on the stem nodes of the remaining stubble. Leaves pinnate with 5–14 pairs of obovate leaflets and a terminal leaflet. Stipules broad and finely pointed. Numerous pinkish red melliferous flowers, borne in erect, conical racemes on long axillary stalks. Root system consists of a deep tap root with a few main branches and numerous fine lateral roots bearing most of the rhizobial nodules. Common or single-cut sainfoin flowers mainly in the year after establishment and thereafter for many years, as this type is very persistent. Giant or double-cut sainfoin lacks persistence and flowers in the establishment year and thereafter for only 2–3 years; it has longer erect but less dense stems than common sainfoin. Flowers cross-pollinated, mainly by honey bees; the flattened, indehiscent seed pods contain a single kidney shaped seed, 4–6 mm, dark olive to brown or black in colour. The proportion of hard seeds in harvested seed crops can be 15–20 percent. Number of seeds kg-1: 50 000 (hulled or podded) and 67 000 (dehulled). Average 1000-seed weight: 20.0 g (hulled) and 14.9 g (dehulled).
Distributed in parts of warm-temperate Europe and Asia, and on dryland,
calcareous soils in western North America. Cultivated in some Mediterranean
environments, e.g. southern
Growth Performs best on deep, well-drained calcareous soils at pH levels of 6.0 and above. It has vigorous seedling growth. Thin dry soils require irrigation to improve forage yield. Adapted to warm temperate climes (Frame, Charlton and Laidlaw, 1998). Erect growth habit, suited to infrequent cutting for conservation (hay or silage ) rather than grazing . Longevity varies with ecotype or cultivar.
It has a spring to autumn growth period, and seasonality of growth varies from the single flush of growth of the common type to the double flushes of the giant type. A rest period is required in late autumn to allow plants to build up the organic reserves in the roots needed for winter survival and initiation of spring growth. It has excellent drought resistance because of its deep-rooting characteristic, and is intolerant of prolonged flooding.
Compatibility in mixture Non-aggressive grasses such as timothy (Phleum pratense ) or meadow fescue (Festuca pratensis ) are compatible. The addition of white clover or birdsfoot trefoil can be advantageous in stands cut for hay and aftermath grazing . Wheatgrasses (Agropyron spp. ) are suitable as companion grass es for dryland conditions (McGinnies and Townsend, 1983; Griggs and Matches, 1991).
Temperature Sainfoin has a wider optimum temperature range for germination and early seedling growth than most other forage legumes (Smoliak, Johnston and Hanna, 1972). Periods of high temperature adversely affect subsequent yields , especially following defoliation , since the plant’s ability to support high metabolic rates is reduced (Kallenbach, Matches and Mehan, 1996).
Winter cold can reduce plant persistence (Jefferson et al., 1994). High reserves of N in legume roots during winter are believed to aid cold hardiness (Volonec and Nelson, 1995).
Light The sainfoin canopy utilizes incident radiation less effectively than alfalfa because of a lower leaf area index (LAI) and less erect growth habit. Flowering is favoured by long daylengths.
Water supply In the absence of irrigation , annual rainfall of at least 330 mm required (Miller and Hoveland, 1995). Water use efficiency, at 15–18 kg DM mm-1 evapotranspiration, is high in spring, equalling that of alfalfa (Bolger and Matches, 1990), but is lower than that of alfalfa later in the season. Irrigation in dry periods aids yield and plant persistence .
Nitrogen fixation Colonization of sainfoin roots is by rhizobial strains common to other legumes from the same (Hedysarae) and related (Galegae) tribes. Rhizobial inoculation of sainfoin seeds is needed when sown onto land that has been free of legumes for several years. A suspension of crushed nodules from another crop has sometimes been used for inoculation.
Nitrogen fixing efficiency is less than that of alfalfa or red or white clovers, since sainfoin requires about 20 mol CO2 to fix l mol of N2 compared with about 10 mol CO2 for the other legumes (Witty, Minchin and Sheehy, 1983). Energy availability may be the limiting factor since sainfoin allocates less assimilate for leaf production and LAI than does alfalfa.
It is cross-pollinated, mainly by honey bees (Apis mellifera), with chromosome numbers of 2n=2x=14 for diploids and 2n=4x=28 for tetraploids. Breeding objectives include improved forage yield, persistence and tolerance of grazing .
Cultivars Modern bred cultivars do not rigidly align
with one or other of the two main original types, common or giant, but
are more flexible in their characteristics. Named cultivars include
Melrose and Nova (
A seed crop can be taken in place of a main hay crop of common sainfoin , or following a hay cut in giant sainfoin, which flowers and seeds twice in a season. Seed yields can reach 1450 kg ha-1 (Hoveland and Townsend, 1985).
Using the Fodder Plant Seeds Regulations for the
Establishment A well-cultivated, uniform and firm seed bed is required for good results. It is best sown direct for successful establishment , but can be undersown in a cereal crop. On dryland in western Canada, seeding sainfoin in alternate rows with Russian wild rye (Psathyrostachys juncea ) rather than sowing the components in the same rows enhanced persistence because of reduced inter-species competition (Kilcher, 1982). Drilling at 20–30 cm depth is advisable, i.e. about twice as deep as red clover , and covering well with soil. On irrigated land, monocultures are usually sown in spring at 40–60 kg ha-1 for dehulled seed and 80–120 kg ha-1 for hulled. Slower-germinating, hulled seeds are sometimes chosen for situations where germination is only wanted after there has been sufficient rainfall to ensure sufficient seedling development. Much lower seed rates are used in dryland conditions. Seed can be protected from fungal attack by dressing with thiophanate methyl (Nan, 1995).
The addition of a non-aggressive companion grass , e.g. meadow fescue (6 kg ha-1) or timothy (2 kg ha-1) increases stand density and reduces weed invasion.
Nutrient requirements An adequate status of available soil P is necessary for successful establishment . After removal of hay crops, soil P and K replenishment is required to maintain plant persistence and yield, though sainfoin is tolerant of soils with a low P status (Miller and Hoveland, 1995). Liming may be necessary to sustain soil pH at 6.0 and above.
Weeds Sainfoin monocultures lack competitiveness against weed invasion compared with sainfoin +grass stands. Serious infestations of perennial weeds should be controlled by herbicides before soil cultivations.
It is tolerant of ‘sainfoin -safe’ herbicides, e.g. MCPB, 2,4–D or bentazone types, applied at an adequate stage of growth. Winter-applied carbetamide is an option for weed grass control in monocultures.
is resistant to many of the pests that attack other forage legumes.
Significant pests noted in the
Diseases Compared with many other legumes, sainfoin is relatively disease resistant. It can be adversely affected by clover rot (Sclerotinia trifoliorum) and sometimes powdery mildew (Erysiphe trifolii) or verticillium wilt (Verticillium albo-atrum).
Forage production Variable, as DM yields may range between 7 and 15 t DM ha-1 depending upon growing conditions. Yields are about 20 percent lower than those from alfalfa , contributory factors including a lower LAI, a less erect canopy structure and less efficient N2 fixation.
This is largely determined by stage of growth at time of utilization
since nutritive value falls with increasing plant maturity and associated
stemminess; data from Quebec,
Sainfoin is protein and mineral rich in comparison with grasses, but its Ca and Na concentrations are lower than in other major legumes. Its mineral composition is shown in Tables 2 and 3. A notable feature of sainfoin is the concentration of condensed tannins in the leaves . Hence its forage does not cause bloat in animals, and the tannins also protect protein in the rumen, thus enhancing the supply of amino acids for absorption in the small intestine of ruminants (Waghorn et al., 1990).
Table 1. Nutritive value of sainfoin (g kg-1 DM) at three stages of primary growth (Means of 3 cultivars over 3 years).
Source: After Gervais, 2000.
Table 2. Mineral composition of sainfoin at three stages of primary growth (Means of 3 cultivars over 3 years).
Source: After Gervais, 2000.
Table 3. Nitrogen and mineral composition of sainfoin.
Source: After Spedding and Diekmahns, 1972.
Both grazed and conserved sainfoin or sainfoin-rich forages are highly acceptable, leading to high animal intake s of forage (e.g. Griggs and Matches, 1991).
Grazing management Rotational rather than continuous stocking is best for stand persistence and production. Sainfoin cannot tolerate overgrazing during the growing season and plant persistence benefits from a 6-week rest period from grazing before winter. The accumulated forage can then be grazed after the plants have become dormant. Common sainfoin is more tolerant of grazing than giant sainfoin. Modern cultivars have been bred for better persistence and regrowth after defoliation .
Conservation management Sainfoin is highly suitable because of its upright growth habit and its pattern of regrowth from axillary buds after defoliation . Shattering and loss of nutritious leaf is a hazard if haymaking is prolonged. Because of a lower buffering capacity i.e. resistance against pH reduction during the ensilage process, sainfoin herbage has a better ensilability than alfalfa .
Sainfoin gives highly satisfactory individual animal performance . Among other legumes, only white clover was superior to sainfoin as judged by lamb growth (Ulyatt, 1981b).
It is a productive protein- and mineral-rich legume suited to calcareous dryland soils, and responds to irrigation on shallow soils. Condensed tannins in the leaves prevent bloating in ruminants and also improve the efficiency of protein metabolism. It has high intake characteristics.
It is slow to establish, and not adapted to a wide range of soil and environment conditions. It is unsuited to intensive grazing .
Gervais (2000); Frame, Charlton and Laidlaw (1998); Miller and Hoveland (1995).
Additional Information by Jason Koivisto and Gerry P.F. Lane, Royal Agricultural College, Cirencester UK. [Pdf-file]