Galega orientalis Lam.
|Author: Dr. John Frame|
Goats rue, galega, fodder galega, eastern galega. (Note: goats rue is the ISTA (International Seed Testing Association) name used for the toxic medicinal plant, Galega officinalis L.).
Perennial with pinnate (sometimes imparipinnate) oval leaves borne on stems, 0.8-2.0 m. Branch stems arise from middle upwards of main stems. Tap-rooted and rhizomatous with overwintered rhizomes emerging in spring to initiate new shoots which eventually take root and become independent plants. Mellifluous inflorescences comprised of bright lilac clusters with 25-70 florets. Full flowering occurs in the year after the establishment year. Cross-pollinated by bees. Pods 2 to 4 cm long containing 5 to 8 kidney-shaped seeds, yellowish green in colour but later light brown. Seed size is 2.5-4.0 mm long, l.7 2.0 mm wide.
Indigenous to Caucasus sub-alpine region. Introduced to Baltic countries, Scandinavia and north-west Russia. Introduced into cultivation circa 80 years ago but only intensively studied, particularly in Estonia, from about 30 years ago. According to Raig (l994) its cultivation and seed production should be possible between 400 and 600 northern latitudes. Circa 6000 ha grown in Estonia (Nõmmsalu and Meripõld, l996). Under evaluation in many central Asian countries and Canada.
Adapted to a range of soil types though not to acidic soils. Grows best on well-drained, light soils with a high pH. Attains maturity 2-3 weeks earlier than lucerne. Perennation dependent on persistence of its rhizome network, but has persisted for 7 to 10 years and more in Baltic countries. Growth habit makes it essentially a species suitable for infrequent defoliation for silage, hay or green fodder.
Season of growth
Spring to autumn, with two-thirds of production by early summer.
Very winter hardy though may be winter-killed by ice cover. Early spring growth susceptible to late frosts.
High tolerance but lower than lucerne.
Tolerance of flooding
Intolerant of waterlogging.
Soil pH of 6.0-7.5. Prefers deep, friable soils. Responds to improved soil fertility from P and K application (also needed to replenish nutrient removal by conservation crops). Not persistent on peaty and wet mineral soils.
Seed inoculation with specific Rhizobium galegae required when first establishing a stand.
Ability to spread naturally
Good ability through rhizomatous growth habit.
Land preparation for establishment
Well-cultivated, uniform and firm seed bed required for good results.
Usually sown by drilling directly into a well-prepared seed bed. If sown under a cereal cover crop, the cereal seed rate should be reduced from normal by 25%.
Sowing depth and cover
Sown at 10-25 mm with firm soil cover to promote seed-soil contact, the deeper sowing depth being required on light soils.
Sowing time and rate
Best sown in early spring. Sowing in May or June gave higher yields in subsequent years than later-season sowings (Raig, l994). Seed rate of 20-30 kg/ha for forage cropping and 4-10 kg/ha for seed production.
Number of seed per kg
Usually 125 000 to 145 000 but up to 250 000.
Percentage hard seed
Seed treatment before sowing
Scarification or acid treatment advantageous if the seed lot has a high proportion of hard seed.
Compatibility with grasses
Compatible with non-aggressive grass companions such as timothy, meadow fescue and smooth-stalked meadow fescue but performance and persistence depressed by competitive companion grasses such as cocksfoot, smooth brome grass and tall oat-grass, particularly when the mixture is N-fertilized (Adamovich, 2000).
Ability to compete with weeds
Low at early establishment but improves with development of the canopy. Weed control by a legume-safe herbicide may be necessary.
Vigour of growth and growth rhythm
Vigorous growth when fully established. Fast regrowth after cutting. Growth peaks in late spring/early summer (up to two-thirds of annual production) with remainder afterwards.
Response to defoliation
Best suited to infrequent defoliation regime.
Generally not tolerant of grazing but regrowth in late autumn following a second conservation cut is suitable for grazing.
The norm in Estonia is a two-cut system with the first cut at early flowering and the second in late autumn. However, high yields have been obtained in Latvia with a 3-cut regime (Adamovich, 2000). A lengthy rest period before the final seasonal cut is needed to allow the plant to build up organic reserves, required for initiation of subsequent spring growth.
Cross-pollinated by bees. Chromosome number 2n = 2x = 16.
All-round improvement of the existing cultivar, but especially to improve forage digestibility. Another objective is to improve tolerance to grazing.
In Estonian trials, averaged over seven years, 7.76-9.18 t/ha with 70-80% galega from pure-sown stands and 8.41-9.33 t/ha with 63% galega from five grass/galega mixtures (Loid et al., l994); late first cutting gave a small yield advantage over early first cutting in the two cuts per annum regime imposed. Yields of 7-8 t/ha for pure-sown stands reported from Norway (Lunnan, l994). In Latvia, with a 3-cut per annum regime over a 12-year period on two soil types, pure-sown galega yielded 8.60-9.47 t/ha while 13 binary grass/galega mixtures averaged 9.36-10.05 t/ha (Adamovich, 2000); nitrogen application increased total herbage yields of the mixtures (l0.73-11.03 t/ha) but at the expense of galega performance and persistence while pure-sown stands did not respond markedly to fertilizer nitrogen application (8.92-10.03 t/ha); again, yields up to 14.23 t/ha which were obtained from three-component (2 grass species/galega) mixtures were superior to those from binary mixtures or multi-component mixtures. In long-term trials in Finland, yields averaged 8.36 t/ha from an annual regime of two cuts (Virkajärvi and Varis, 1991).
Suitability for hay and silage
Suitable for both. Better retention of leaves after drying for hay than lucerne. Heavy wilting and an effective silage additive is advisable when ensiling pure-sown galega because of its high proteinlow water soluble carbohydrate characteristic and high buffering capacity (Pahlow et al., 2000). Grass/galega mixtures have better ensilability characteristics than pure-sown galega stands because of the grass characteristics.
Highest at pre-flowering stage. Digestibility, crude protein and water-soluble carbohydrate values decrease with plant maturity and its associated decrease in leaf:stem ratio and increase in fibre content (Nõmmsalu, 1994, Nõmmsalu and Meripõld, 1996). In contrast to most forages, the stubble remaining after harvesting a seed crop is of moderate feeding value and can be ensiled or hayed.
Acceptable forage to livestock as silage or hay.
Seed harvesting methods
Direct harvesting is employed.
Yields up to 690 kg/ha have been achieved during the second harvest year in Estonian trials (Meripõld, l994). Five-year average yields ranged from 254 to 357 kg/ha depending on row spacing and sowing rate with low seed rates (4-8 kg/ha) and wide row spacings (37.5-62.5 cm) proving best.
The only commercial cultivar is Gale, released jointly by Estonian and Russian plant breeders in 1987.
Diseases and pest
Resistant to diseases and pests but further confirmation will only emerge if and when much larger areas of galega are grown.
Productive, N-fixing, protein-rich forage adapted to a range of soil and environmental conditions. Good long-term persistence. Suitable for hay or silage.
Unsuited to grazing. As yet only one cultivar available. Low forage digestibility (lower than lucerne and main clovers). Poor persistency on wet soils.
Intake and milk yield from galega and red clover (T. pratense) silages, either pure or mixed with grass (Festuca pratensis - meadow fescue) were at least equal to or better than grass silage when digestibilities were equal (Tuori et al., 2000).