Desmodium discolor Vog.

Meiboma discolor Vog.

Horse marmalade (South Africa), marmelada de cavalo (Zambia, Brazil), discoloured clover (Fiji).

Upright perennial plant growing to a height of 2.5 to 3 m with stems which become woody when mature. Has a well-developed, deep root system. Trifoliate leaves are hairy and dark green, although they often have a reddish tinge when the plant is growing vigorously. Flowers are pink or white and borne in large open panicles. Seed is fine, about the size of lucerne (alfalfa).

Found in the subtropics of Brazil (São Paulo, Mato Grosso), Argentina (Misiones), Paraguay. It has been introduced to Colombia, Cuba, Fiji, South Africa and Zambia.

It has a wide range, from relatively dry to subhumid (Otero, 1952).

Does not tolerate "wet feet . " Waterlogged sites should be avoided.

Does best in well-drained, deep fertile soils but will grow on a wide range from acid sandy loams to loams (Whyte et al., 1969), but if the soil is too acid, liming will benefit it (Otero, 1952).

Performs best on a well-prepared seed bed with cultivation early in the planting season to destroy young weed growth. Subsoiling to a depth of 40 cm is beneficial in hard soils (Otero, 1952).

On a prepared seed bed it can be drilled in rows 0.40 m apart; for seed purposes sowing on a square 0.60 x 0.60 m allows interrow cultivation. It can also be sown by cuttings. In Zimbabwe, (Boultwood, 1964) it is often sown in maize, which acts as a nurse crop providing a protective canopy, reducing soil crusting from raindrop impact and preventing rapid drying. Undersowing is best done after at least one cultivation of the maize to control the early flush of weeds, and the seed is broadcast between the maize rows onto the loose soil. Seed is broadcast on the surface or drilled at 1 to 2 cm and rolled after being lightly covered.
It is planted just before the rains or early in the growing season (October to November in Brazil). Sowing rate is 5 to 8 kg./ha in 0.60 x 0.60-m rows; 30 to 35 kg./ha broadcast or seeded in 0.40-m rows. One hundred litres of seed weigh 40 kg.
Trials at Henderson Research Station, Zimbabwe (Boultwood, 1964), indicate that D. discolor may be successfully introduced into rough veld grazing. The land is disc-harrowed in strips through the veld, after burning just before the rains. This reduces the competition from the grasses and provides an adequate seed bed.

An average sample of seed contains 12 percent rotten seed, 27 percent viable seed which will germinate immediately, and 61 percent hard seed (Otero, 1952).

Dormancy can be broken by treatment with concentrated sulphuric acid. Nicking the seed will also accomplish this (Otero, 1952).

No trials have been undertaken to determine requirements. In Zimbabwe, 200 kg./ha single superphosphate are applied for establishment and a similar quantity is used for yearly maintenance.

No measurements have been undertaken. It nodulates freely and grass growing in association with it assumes a darker green colour.

Stands should be allowed to become well established before being used intensively, and it is advisable to leave first-year stands to grow for seed production and then graze them in the dry season. Although cattle will graze it at all stages of growth, they will not take the stems if they are mature and woody. Boelcke (1964) recommends cutting and feeding the cut material to cattle.

Resists fire very well.

Self-fertile, chromosome number 2n = 22 (Rotar and Ukio, 1967).

Makes excellent hay in Brazil. Can be cut at a height above 10 cm and will give five cuts a year. The hay should be handled carefully to prevent leaf shedding. Also makes excellent silage if cut at a height of 1.5 m. It is readily harvested with a flail-type forage harvester. It is advisable to add molasses at the rate of 2 percent by weight of the green material (Boultwood, 1964).

• Chemical analysis and digestibility: 

Otero (1952) recorded the figures shown in Table 15.4. In Zimbabwe, the protein content of the dry matter of the green material was recorded as 15.5 percent and of silage made from material cut in midseason as 11 to 13 percent.

• Palatability: 

All reports indicate that the plant is extremely palatable.

So far only hand harvesting has been practised. The seed heads are cut, allowed to dry thoroughly and are fed through a slow-running hammer mill. A combination of winnowing and sieving then cleans the seed.

Up to 200 kg./ha of clean seed can be expected in Zimbabwe and Otero (1952) records 150 kg./ha in Brazil, but up to 300 kg. from hybrids.

The plants differ in their resistance to nematodes, and selection for nematode-resistant plants is proceeding at the Henderson Research Station in Zimbabwe. A rustlike fungus attacks the plant in the winter in Brazil (Otero, 1952).

No inoculation has been found necessary at the Henderson Research Station, Zimbabwe (Boultwood, 1964) but the Desmodium type Rhizobium may be beneficial.

Boultwood (1964); Otero (1952).

In the young stages, weeding is recommended. It rapidly grows taller when it becomes established and dominates weeds.

At Mt. Makulu in Zambia, severe damage occurs early in the season from attacks of a "flea beetle" (Monolepta gossypiperda Br.) (van Rensburg, 1967).

It prefers warmer climates (Boelcke, 1964) . It starts growing early in the season as soon as temperatures rise. Young plants are susceptible to frost, but established plants are little affected.

Grows well in natural pastures and in maize.

Grows slowly in the first year and is of little use until the second year (Boultwood, 1964). At Katapola Farm Institute in Zambia, it survived competition and produced vigorous growth (van Rensburg, 1967).

A short-day plant, it flowers in April and seeds in May in Brazil. It is able to tolerate deep shading in the early stages of growth.

Twenty-four to 30 tonnes of green material per hectare have been harvested in Zimbabwe, and in Brazil 3 430 kg./ha, which produced 1 000 kg. of hay (Otero, 1952).

It is especially useful for supplementary protein-rich grazing in late summer and autumn when the feed value of grasses is declining.