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Cicer Milkvetch (Astragalus cicer)

Plant Species
From Montana Interagency Plant Materials Handbook *
 By S. Smoliak, R.L. Ditterline, J.D. Scheetz, L.K. Holzworth, J.R. Sims, L.E. Wiesner, D.E. Baldridge, and G.L. Tibke

Cicer milkvetch is native to the European continent, found there in moist places along streams and ditches, in hedges and wood margins and in open woods. Its natural range extends from Finland and northern Sweden to northern Spain, eastward to north-central and southeastern Russia. Collec-tions of cicer milkvetch were introduced into the United States in the 1920's and made available to agricultural scientists for testing as a possible forage legume. Seed of cicer milkvetch PI-66515 was introduced from Sweden in 1926 by Dr. Robert Frier, Director of the Stockholm Botanical Gardens. Soil Conservation Service plant materials centers in the west received seed of this accession in 1935.

Description

Cicer milkvetch is a long-lived, perennial legume with a vigorous, creeping, root system and a short, stout taproot. The stems are large, hollow and succulent. Their growth is upright when young, becoming decumbent to trailing as growth continues. Stems reach a length of 4 feet at the flower stage, and may reach a length of 10 feet in one season under ideal conditions. The above-ground height of the foliage, however, seldom exceeds 3 feet. The leaves are 4 to 8 inches long and consist of 10 to 13 pairs of leaflets attached to a midrib, plus one terminal leaflet. The lower surface of the leaflet is sparsely hairy. Pale yellow to white flowers are borne on 4- to 8-inch flower stalks that grow from the base of the leaves. Each stalk has from 15 to 60 flowers.

Adaptation

The wide range of variability in cicer milkvetch permits it to be grown in a wide variety of environments. It does well on all soil textures, but performs best on moderately-coarse-textured soils. It tolerates slight acidity to moderate alkalinity, and has been established on wet soils with 9.8 pH. Tolerance to alkalinity is increased with higher soil moisture levels. It performs well on poor, infertile soils and is useful in stabilizing critical or disturbed sites.

The optimum soil moisture range is between 18 and 35 acre-inches annually. Cicer milkvetch performs well on subirrigated sites where the ground water is within 3 feet at the surface. It also exhibits good drought tolerance, and has been established on dryland sites in Montana and Wyoming receiving less than 14 inches of precipitation annually. Cicer milkvetch has been grown in Montana and Wyoming at elevations from 2,000 to 7,000 feet, but performs best where it receives maximum heat units. The underground crowns and rhizomes enable the plants to avoid damage from severe cold.

Good to excellent performance has been reported from the coastal areas of Alaska south to Las Cruces, New Mexico, and from the Central Plains west to the Cascade-Sierra ranges. However, the principal range of adaptation is the Rocky Mountain region.

Limitations

Cicer milkvetch is susceptible to root-, crown- and stem-rot (Sclerotinia trifoliorum), a disease common to most forage legumes. Presence of the disease is indicated by wilting and death of aerial portions of individual plants, and by black sclerotial bodies found on or inside the stems. Recovery of diseased cicer milkvetch plants is common, due most probably, to rapid regeneration of new plants from the prolific rhizomes.

The seed of cicer milkvetch has inherent low germination due to the hard seed coat. The hard seed coats must be fractured mechanically or broken down chemically to permit air and moisture penetration before germination can proceed.

Use for Hay

Yields of cicer milkvetch cut for hay are comparable to alfalfa in the longer growing season areas when the proper cutting system is used. Because of slow spring growth and slow recovery after hay harvest, cicer milkvetch is harvested only twice in the areas of Montana and Wyoming where three cuttings of alfalfa are obtained. The protein content of cicer milkvetch equals or exceeds that of other legumes. The high protein content of this legume is due, in part, to the high leaf/stem ratio (40 percent higher than alfalfa), and its ability to hold its leaves during drying and baling. The moisture content of green forage of cicer milkvetch averages four to eight percent higher than alfalfa or sainfoin when harvested. Drying time of the hay is about three days longer than other legumes. Crimping the hay as it is cut, or turning the windrows, will reduce drying time by 30 percent to 50 percent. Cicer milkvetch is more tolerant of late spring and early fall frost than alfalfa. Stands often improve with age in favorable environments because of prolific rhizomes. This strong sodding characteristic also makes cicer milkvetch competitive in a mixture with grasses.

Use for Pasture

Cicer milkvetch is especially well-suited to use as pasture. It is readily eaten by all classes of livestock as either hay or pasture, as well as by antelope, deer and elk. No cases of bloat have been reported from grazing livestock. It contains no harmful alkaloids, nor does it accumulate selenium in toxic amounts. The sodding characteristic of cicer milkvetch resists damage from overgrazing. Recovery from grazing is rapid as opposed to the slow recovery when cut for hay. New shoots arise from the base of the lower leaves as well as from crown and rhizome buds. Close grazing or clipping apparently stimulates the growth of new shoots from all three locations. In grass-legume mixtures, the highly competitive characteristic of cicer milkvetch requires an equally competitive grass if the mixture is to be maintained with equal proportions of each. Grasses that are compatible with cicer milkvetch are creeping foxtail, `Regar' meadow bromegrass, orchardgrass and tall fescue. Smooth bromegrass and reed canarygrass severely suppress the growth of cicer milkvetch.

Seed Production

Under irrigation, the average seed yields in Montana and Wyoming range from 400 to 600 pounds per acre. Dryland seed fields may produce 100 to 200 pounds per acre under good moisture conditions. Bumble bees are the primary pollinators of cicer milkvetch, and are necessary for good seed crops. Observations indicate that one bee per-square-rod (160 per acre) appears to be the average concentration over a number of years. Honey bees are also capable of pollinating cicer milkvetch and will enhance seed yield. Control of soil moisture is necessary for maximum seed yields. Total moisture (rainfall plus irrigation) should not exceed 16 to 20 acre-inches per season. High moisture availability promotes vegetative growth at the expense of flower production. The seed crop matures and is ready for harvest about the first week in September in the lower elevations of Montana and Wyoming. There is little danger of seed shattering if harvest is delayed a few days or even several weeks. The most satisfactory harvest procedure is to windrow the crop and allow it to dry thoroughly before combining. The seed pods should become brittle and fracture easily. The pods collect moisture readily from the air, and will become leathery under a dew or even high relative humidity. Threshing is delayed during the day until the pods are brittle. High cylinder speeds and narrow cylinder-concave spacing are necessary to thresh the pods, and will not injure the hard-coated seed. Seed fields are kept in production for no more than five years, because of the loss in plant vigor and steady invasion of weeds in the older stands.

* The Montana Interagency Plant Materials Handbook (EB69) is no longer in print, but is available for viewing in
Montana County Extension Service and National Resource Conservation Service Offices.