Sainfoin

Characteristics

Non-bloating

Sainfoin (Onobrychis viciifolia Scop.) is a perennial cool-season legume used for forage production. It is an introduced species, brought over from Europe, parts of Russia and Asia. New sainfoin populations have shown promise for persistence under grazing in alfalfa-sainfoin mixtures, with comparable yields to alfalfa/grass mixes. Sainfoin is non-bloating, making it suitable for hay and pasture.

Non-bloating is due to the presence of condensed tannins in the legume. These tannins will bind with proteins released from plant tissues in the rumen, preventing their degradation and allowing them instead to be digested as by-pass protein. Without tannins, proteins are quickly digested, combining with rumen fluid to form stable bubbles, which causes bloat.

Other characteristics

Sainfoin is a forb (broad-leaved plant) with erect stems up to 1 m (39 in.) in height. Stems are hollow and appear coarse but are quite succulent, and grow from a root crown. The roots are deep, branched taproots with many fine lateral roots; the main taproot is very stout, and the crown is branched.

Leaves are comprised of 11 to 29 leaflets that are paired up the stem except for a single terminal leaflet at the tip. Flowers grow on a long, spike-like terminal head, which are narrow at the tip and wide at the base. These heads have up to 80 rosy-pink flowers attached to short stalks that connect them to a main stem. Plants tend to produce flowers and seeds starting from the bottom of the flower spike, working upward.

Seedpods are tough and fibrous, with a network of raised veins, and stick tightly to a single enclosed seed. The pods shatter easily from the plant when mature. When threshed, the seed pod is left attached to the seed. The seed pod is usually not separated from the seed prior to planting. The seed itself is large, kidney-shaped and greenish-brown for a perennial forage legume.

One kilogram (2.2 pounds) of sainfoin yields:

48,000 seeds with pods, or
66,000 seeds with no pods

Where it grows

Sainfoin is adapted to at least 2 of the 7 Natural Regions in Alberta: Grassland and Parkland Natural Regions. These include brown, dark brown, black, and grey-wooded soil zones.

Well-drained, dry sites not subject to flooding or sub-irrigation at the root zone are ideal for growing sainfoin. Soils must be of neutral to alkaline pH, weakly saline, calcareous (high calcium), and moderately fertile. Sainfoin is more drought tolerant than alfalfa, but grows well in areas with 300 to 500 mm of annual precipitation. Prolonged drought will diminish a stand; this legume is not adapted to long-term production on non-irrigated semi-arid locations.

Seeding requirements

Seedbeds

Seedbeds need to be well-packed and uniform before and after seeding. Though sainfoin has large seeds compared to other forage legumes, it still needs to be seeded shallow: no more than ¾ inches (2 cm) deep.

Avoid fields with heavy trash-cover; the soft seedbed is more difficult to pack, dries out quickly, may increase the depth of the seedbed, and the trash may harbour a surprise crop of highly competitive weeds. It also reduces seed-to-soil contact which is needed for successful germination.

Sod-seeding sainfoin into existing grass stands have not been successful with recent trials in the western USA. However, anecdotal evidence in southwestern Alberta has shown that sainfoin may establish and persist in areas where sainfoin hay has been fed, or plants are able to grow to maturity so that seed can spread by grazing animals or wind. Otherwise, sainfoin should be sown in cultivated seedbeds.

Field fertility

Fields should be fertilized to soil test recommendations, and any deficiencies corrected. Alkaline soils tie up available phosphorus, but sainfoin has shown to be unresponsive to phosphorus application in some trials. Mycorrhizal complexes between sainfoin roots and fungi are formed to improve phosphorus uptake by the plant. Low-level nitrogen applications may be beneficial for improved nodulation, or seeding with other legumes in nitrogen-deficient soils.

Sainfoin should be inoculated with the correct rhizobia species before seeding to allow nodules to develop. However, commercial strains of nitrogen-fixing bacteria specific to sainfoin are often unavailable, so a clover or alfalfa inoculant may need to be used instead. Scarification is not possible as most sainfoin seed is sold with pods on.

Timing

Dryland sainfoin should be seeded before the end of June in most parts of Alberta. Late-autumn seeding has also been successful, as long as it is done when the ground surface is dry and is too cold for seeds to germinate. Annual cover crops should be avoided unless there are areas where erosion could damage the seedbed.

Seedlings are not competitive; sainfoin germinates well and establishes slowly, with spring-seeded sainfoin normally well established by fall.

Row seeding

If sainfoin is mixed with other legumes or grasses, it's best to seed in alternate rows, with sainfoin in its own row. Cross-seeding sainfoin in perpendicular rows may improve plant density when in mixtures. Row spacing should not be less than 22 cm (9 inches) to reduce competition between species.

Seeding rate and placement

The seeding rate of sainfoin should be based on pure live seed (PLS). Assuming that PLS is 95%, a pure stand of sainfoin should be precision-placed at 30 kg/ha (27 lb/ac).

Suggested seeding densities are 40 to 60 seeds/metre of row (12 to 18 seeds/foot of row, when row spacing is 7 inches). This results in 175-250 seeds/m2 (16 to 23 seeds/ft2).

Row spacing for sainfoin should be 18 cm (7 inches). This spacing should be double if another legume is included, and the seeding rate halved. For instance, if seeded in alternate rows with alfalfa in a 50-50 seed mix (50% sainfoin and 50% alfalfa), row spacing for sainfoin would be 36 cm (14 inches), and seeding rate 14 kg/ha (12.6 lb/acre).

Forage varieties

Sainfoin breeders recognize 2 types of sainfoin, referring to their ability to regrow after cutting:

single-cut
double-cut

Cultivars

Available cultivars produced in the US include:

Eski (1964): single-cut variety
Remont (1971): double-cut variety for northern and southern regions
Delaney (2007): multi-cut variety to replace Remont
Renumex (1979): double-cut variety for northern and southern regions
Shoshone (2005): synthetic composed of single and double-cut varieties
Mountainview (2013): a double-cut for northern conditions

Canadian geneticists have produced 2 single-cut varieties for northern conditions:

Melrose (1972)
Nova (1980)

Recommended use

All cultivars are recommended for:

hay and pasture use
irrigation and dryland
as parts in mixtures with grasses and other legumes

However, Mountainview was selected for its improved regrowth performance in mixed stands with alfalfa. It is one of the more preferred varieties because of its ability to regrow quickly and remain in the stand when combined with alfalfa. It is also more adapted to northern areas in Canada than most American cultivars.

Using sainfoin for hay

Since sainfoin grows upright, it makes it easy to harvest for hay. It also has excellent leaf retention – better than alfalfa – and can be cut to at least 50% flowering to maximize yields. Sainfoin can work in either a 2-cut system under irrigation or a 1-cut system in drier areas.

Even though sainfoin tends to have higher moisture content than alfalfa, it still cures very well for hay due in part to the hollow stems. It also yields 80 to 90% of alfalfa hay.

Using sainfoin for forage

Sainfoin is highly palatable, with cattle often selecting it over alfalfa when grazing. Research has shown it has lower acid detergent fibre (ADF) and neutral detergent fibre (NDF) levels than alfalfa, along with increased digestibility of its stems.

Feed quality tends to decrease with advancing maturity; by the seed-shattering stage the amount of leaf loss will make feed stemmy and unpalatable.

Pasture system

Sainfoin is best suited to a rotational grazing system that allows for significant amounts of residual leaf and stem material behind (such as in a take-half leave-half grazing system) so that it can regrow. It depends mainly on the photosynthesis of remaining leaves to provide enough energy to regrow.

Sainfoin has a lower leaf area index than other legumes like alfalfa, or rather, lower leaf surface area for gathering energy for root storage and growth. This means that most sainfoin varieties are slower to regrow and need more time to recover. Newer varieties like Mountainview have improved regrowth compared with older cultivars, allowing them to compete with alfalfa.

Grazing

Sainfoin can be grazed mid-summer or stockpiled for fall grazing. Maximum yields are expected when sainfoin is at 50 to 100% bloom, however better regrowth would be expected when it is grazed in the vegetative stage. Sainfoin in vegetative stage is also higher in quality and more palatable than when it's mature.

Frequent and severe grazing will quickly diminish a sainfoin stand, especially when grazed in its vegetative stage. Sainfoin needs to have an opportunity to reseed itself and store carbohydrates in its roots at least once every few years to be able to persist in a forage stand. Rather, a sainfoin stand should not be grazed until it is fully mature once every two or three years.

Sainfoin has good leaf retention and frost tolerance, making it ideal for fall grazing. Be sure to rest it four to six weeks before a killing frost in order to allow the plants enough time to build up their carbohydrate reserves to survive the winter.

Recent studies conducted in Alberta and Saskatchewan has looked at the possibility of including new sainfoin varieties with alfalfa for grazing. They have found that these new varieties, such as Mountainview, are more competitive with improved regrowth rates compared with some older varieties. These studies have also shown that including 20 to 30% sainfoin in an alfalfa pasture stand significantly lowers and in certain cases eliminates, the risk of bloat.

Resources

Soil fertility

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