Desmodium incanum DC.
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Desmodium incanum DC.
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Leguminosae
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Author: L.’t Mannetje |
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Kaimi, kaimi clover, creeping beggar weed (En), Pega-pega (Sp, Port). Origin and geographic distribution Originally from southern United States to Uruguay and Argentina, this species is now widely distributed in the wet tropics and some areas of the wet subtropics. It is abundant on volcanic soils in Hawaii, Fiji, Vanuatu and other Pacific Islands. Ascending to erect perennial herb or low shrub to 60 cm tall, rarely to 3 m, but in a grazed pasture situation it is typically prostrate and less than 20 cm tall. Stem trailing, fibrous to woody, sometimes beneath the soil surface, rooting readily at the nodes; root system deep, well-branched. Leaves trifoliolate, stipulate, petiolate; stipules at least partially connate abaxially, 3-11 mm x 1-3 mm, long persistent; petioles up to 3.5 cm long; leaflets very variable, mostly elliptical, terminal leaflets 2-9 cm x 1.5-4.5 cm, lateral ones up to 6 cm x 3 cm; leaflets on upper leaves tending to be narrower than those on lower leaves, dark green on the upper surface and often with a paler streak along the midrib, paler and densely pilose beneath. Inflorescence a terminal or axillary raceme, up to 20 cm long; flowers solitary or in fascicles of 3; pedicel 4-10 mm long; flower blue, red or purple, the standard up to 6 mm long. Pod up to 4 cm long, the upper margin straight, the lower strongly indented, covered with hooked hairs, with up to 8 articles of 3.5-5 mm x 2-3.5 mm. Seed oblongoid to kidney-shaped, 1 mm x 0.5 mm, light brown (Hacker 1992). Use Forage in mixed grass/legume pastures, tolerant of heavy grazing and low soil fertility. Particularly used in Fiji and Vanuatu, but not widely recommended elsewhere. Properties Nitrogen concentrations of 2.0-2.5% have been reported. Toxicity Kaimi is not toxic to livestock, but palatability may be reduced by tannins. Ecology Kaimi grows best in regions with annual rainfall of 1500-3000 mm, but will persist and spread in areas receiving 1000 mm. Optimum temperatures are 30 /25°C during the growing season, tolerant of light frosts and temporary flooding. Where naturalized it is particularly common along roadsides, wasteland and other disturbed ground. Soil requirements Kaimi is best adapted to fertile, neutral to slightly alkaline soils, but may be grown on a wide range of soil types from sands to light clays, pH 4.0-8.0. It responds to lime and P, but these are not normally considered essential. Propagation and planting Kaimi is generally propagated by seed, which may require treatment with concentrated sulphuric acid for 10 minutes before sowing. However, vegetative propagation is also possible. A well-prepared seed-bed is recommended for the most reliable establishment, but seed may also be broadcast into an existing pasture. Recommended sowing rate is 5 kg/ha at ca. 5 mm depth. It grows with a range of pasture grasses, but is usually associated with stoloniferous or rhizomatous species. D. incanum is self-fertile, but some outcrossing is believed to occur. Rhizobial requirements It is recommended that the seed be inoculated with the special strain of Bradyrhizobium. Growth and development Initial growth is slow, but later growth rates improve, provided moisture is adequate. Trailing stems begin to develop some 6 months after sowing. In regions with a pronounced seasonal climate, growth during the dry season is slow. At higher latitudes, flowering occurs when daylengths shorten. It is spread by animals and humans because of the hooked hairs on the pods. Diseases and pests D. incanum is reported to be sensitive to Peanut Mottle Virus and may act as a source for this virus for cultivated groundnuts in the United States. Several fungal diseases have been recorded, as well as little leaf and desmodium mosaic virus, but they rarely cause serious problems. Seedlings may be damaged by cutworms, and in Hawaii the rose beetle and the cyst nematode Heterodera trifolii may cause damage (Lenné and Stanton 1990). Performance The stoloniferous habit of this species enables it to withstand heavy close continuous grazing. It is amongst the more persistent legume species under heavy grazing (Cameron et al. 1989). Kaimi can yield up to 6500 kg/ha of DM but is normally considered to be low-yielding. Seed yields can reach 200 kg/ha. Under lenient defoliation, and particularly with high P input, it is reported to be lower-yielding and to fix less N than the more widely grown D. intortum. Links
Cameron D.G. et al. (1989); Hacker J.B. (1992); Lenné J.M. and Stanton J.M. (1990) |