Cynodon nlemfuensis Vanderyst

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Graminae

Common names

Giant star grass (Nigeria), African star grass (Australia), robust star grass.

Description

A large, robust, non-rhizomatous grass, deep-rooted. C. nlemfuensis has two distinct varieties: var. nlemfuensis is somewhat finer and less robust than var. robusta and resembles a very large C. dactylon except that it has no rhizomes (Harlan, de Wet & Rawal, 1970). The inflorescence has four to nine racemes, each 4-7 cm long. Var. robusta has seven to 12 racemes, each 6-13 cm long (Chippendall & Crook, 1976). Inflorescence is one whorl (occasionally two), slender, green or pigmented.ô

Distribution

Var. nlemfuensis occurs mainly in Kenya, Uganda and Tanzania with small outliers in Zaire and Ethiopia. Var. robusta has a similar base with more representation in Ethiopia and eastern Zaire.

Soil requirements

It has a wide range of soil fertility and can mobilize and recycle subsoil nutrients, especially calcium, to offset the increasing acidity from high levels of sulphate of ammonia application (Mohamed Saleem, Chheda & Crowder, 1975).

Sowing methods

It is propagated by rooted runners.

Response to defoliation

At Fashola Livestock Farm in Nigeria in the derived savannah zone, C. nlemfuensis maintained a good stand and productivity when cut fortnightly to a height of 2-3 cm (Ahlgren et al., 1959). Later, Chheda and Mohamed Saleem (1972) showed that cultivar 1B.8 should be cut to a height of 18 cm for optimum herbage production.

Dry-matter and green-matter yields

Strickland (1976-77) recorded an average dry-matter production of 1 600-2 000 kg DM/ha per month in summer and 4001 000 kg/ha per month in winter from three accessions tested at Samford, Queensland (lat. 27°22'S, 1 050 mm rainfall, humid subtropical climate). In Nigeria the cultivar 1B.8 yielded 25 600 kg DM/ha over two harvests between 19 August and 26 October 1971 (Mohamed Saleem, Chheda & Crowder, 1975).à

Cultivars

Cultivar 1B.8 is a deep-rooted, non-rhizomatous variety and lB.1 is a local variety in Nigeria, the local variety being consumed to a greater extent than 1B.8 (Ademosun, 1973). Dry-matter intake values were 1.59, 1.36 and 1.51 kg per 100 kg body weight for the 1B.8 variety harvested at four, seven and ten weeks of age and fed to goats. The corresponding values for the local lB.1 variety were 2.09, 2.26 and 2.20 kg per 100 kg body weight (Ademosun & Kolade, 1973).

Palatability

It is extremely palatable, especially when young.

Chemical analysis and digestibility

Mohamed Saleem, Chheda and Crowder (1975) recorded a crude protein of 7.8-8.0 percent, potassium content of 2.8 percent, a range in phosphorus of 0.14 to 0.26 percent and of calcium from 0.16 to 0.31 percent, the latter from an application of 2.5 t/ha of calcitic limestone. Ademosun and Kolade (1973) compared two varieties of C. nlemfuensis var. robusta (local or 1B.1 and var. nlemfuensis (1B.8) and found that when harvested at six weeks both varieties yielded about 3 t/ha. Digestibility of dry matter by goats was about 60 percent for both varieties.

Natural habitat

Disturbed areas in grassland, cattle paddocks, verges, on moist alluvium.

Fertilizer requirements

Cultivar 1B.8 requires 0.22 percent phosphorus in herbage for optimum production. It responds to heavy dressings of nitrogen.

Genetics and reproduction

Var. nlemfuensis is mostly a diploid, but a tetraploid race has been encountered under cultivation and it crosses rather easily with the diploid variety of C. dactylon. Var. robusta is a diploid with tetraploid races under cultivation.

Seed production and harvesting

Strickland (1976-77) could only obtain a trace of seed from three accessions tested at Samford, Queensland, in 1976-77.

Animal production

Owing to the confusion of nomenclature, figures are difficult to verify. Plate 33 shows a herd of Boran cattle grazing what is probably a C. nlemfuensis pasture in Kenya.

Further reading

Harlan, de Wet & Rawal, 1970; Strickland, 1976-77; Vicente- Chandleretal., 1974.