Alpine kidney vetch
Anthyllis vulneraria ssp. alpestris (Schröter, 1888)
Semi-rosette herbaceous plant, perennial or annual to triennial, with a thick rootstock.
Stem short, compact, ascending to erect, hairs appressed, lower part with one to three stem leaves.
All foliage leaves almost glabrous, fleshy; unlike Anthyllis vulneraria the basal ones are mostly non-pinnate. Petioles often reddish.
Flowering heads large, calyx 13 to 14 mm long, most of the races with golden corolla.
SUITABILITY FOR RESTORATION
This plant of the central and southeast European mountains occurs on similar sites to Anthyllis vulneraria. It is very common in the Alps, but only in the subalpine and alpine zones. The species prefers calcareous soils, but is also found on lime-deficient ground. On calcareous, poor grasslands it sometimes represents the stand structure. The species is also frequently found on talus sites; it grows in the Alps at altitudes of up to 3 000 m.
On calcareous ground the plant is particularly suitable for restoration of slopes and rocky, planed soils of the subalpine and alpine zones.
Seeds 2.4-3.2 mm long, 1.6-2 mm wide and 0.8-1.2 mm thick; broad-ovoid, sometimes with a slight lateral indentation.
Radicle clinging, not sticking out.
Hilum centrally ventral, round, whitish, with dark border.
Surface colour significant: yellow up to two-thirds, remaining part green; glossy, smooth.
Pod one-seeded, inflated oblique-ovoid, pilose, dark to blackgrey.
Thousand seed weight: 3.2-3.5 g.
(soil and climate)
Alpine kidney vetch is extremely undemanding and adaptable, while tolerating fertilization intermediately. Even poor habitats with shallow, nutrient-deficient soils are well suited. Sites that are too damp and clay and peat soils are not suitable. The pH should not be below 6, otherwise a deficient root development may form. Alpine kidney vetch prefers arid weather having a low transpiration coefficient. It is self-tolerant and a good previous crop for cereals, sweetcorn and rape. As for all legumes, there should be a long crop rotation in order to prevent an accumulation of fungal pathogens.
Alpine kidney vetch should be threshed close to the ground. A flat, fine, crumbly seedbed without stones is preferred.
Open sowing is possible throughout the year. In order to guarantee a satisfactory crop yield the following year, seeds should be sown up to July at the latest. Alpine kidney vetch is extremely suitable as a nurse crop for summer barley or durum. It does not cause any problems during sowing.
Seed rate: 8-10 kg/ha.
Row spacing: 12-25 cm, depending on the construction of the seeder.
Phosphorus and potassium: alpine kidney vetch requires very few nutrients.
In autumn before cultivation, basic fertilization with manure (15-20 tonnes/ha) is considered sufficient. Using mineral fertilizer, an application of 60-80 kg/ha P2O5 and 100-140 kg/ha K2O is recommended, depending on soil content.
Nitrogen: kidney vetch meets its nitrogen requirements by means of nitrogen-fixing bacteria. As for all legumes, fertilization with 20-30 kg/N is recommended for open sowing in order to stimulate juvenile development.
MAINTENANCE AND WEED CONTROL
Compared to common kidney vetch, alpine kidney vetch has a slower juvenile development and produces conspicuously less leaf mass. Thus, populations with low competition with weeds are only possible with mechanical weed control, optimally combined with chemical controls. The plant is not sensitive to the use of curry combs. As for all legumes, specific weed control with herbicides is not always possible. In this context, experiences in clover seed production should be mentioned. However, compared to most clover species alpine kidney vetch does not tolerate butyric acid (MCPB).
Pests and diseases: Anthyllis vulneraria ssp. alpestris is usually healthy, although several fungal diseases (mildew, focal spot disease, rust and stem fungal) are possible. In the north of Italy, root rot caused by fungal pathogens appears from time to time, which can lead to heavy losses.
Most alpine kidney vetch plants die off after seed ripeness. Plant survival depends on origin ecotype and sowing time. A second harvest the following year can be profitable if the reproductive populations together with the juvenile plants - grown through seed shedding - remain sufficiently dense. In this case, densely grown populations have to be cut after the first harvest in autumn in order to minimize losses over winter.
HARVEST AND YIELDS
Resistance to lodging: low.
Shattering tendency: extremely high.
Ripeness: at time of ripeness florets change colour to silver-grey and pods become dark to black-brown. Seeds become firm (nail test) and change colour to a typical green-yellow. Because of the plants unequal ripening and high shattering tendency, harvesting is only recommended when at least 60 percent of the flowers are ripe. Often this state of ripeness is reached when the third axis of flowers at the stem is ripe for threshing.
Ripening period: about one week earlier than common kidney vetch, mostly in the first decade of July.
Harvesting technique: because of limited leaf mass the stems lie close to the ground and therefore the board has to be kept very low. Swath threshing is not recommended because of high losses through seed shedding. Threshing has to be carried out with great care.
Crop yields: yield forecasts amount to between 100 and 300 kg/ha. Depending on ecotype and weed infestation a second harvest is possible.
Depending on the thresher, harvested seeds can still remain covered with 60 to 90 percent of the pods. As is common practice in seed production, seeds should be dried gently immediately after harvesting. Hulling the seeds should be carried out with special machines (clover rubber).
Seed propagation trial