Digitaria milanjiana


Scientific name

Digitaria milanjiana (Rendle) Stapf

Synonyms

Digitaria kilimandscharica Mez
Digitaria milanjiana (Rendle) Stapf subsp. eylesiana Henrard
Digitaria mombasana C.E. Hubb.
Digitaria swynnertonii Rendle
Panicum milanjianum Rendle

Family/tribe

Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Paniceae.

Common names

digit grass, milanje finger grass, woolly finger grass , milanjiana (Spanish).

Morphological description

A variable, stoloniferous (sometimes rhizomatous or tufted) perennial with erect culms to 150 cm high at maturity, and leaf-blades to about 40 cm long and 1.3 cm wide (often narrower);  leaf dimensions, colour and pubescence vary with provenanceDigitate or subdigitate panicle comprising mostly 3-12 racemes (rarely 2 and up to 18), 8-25 cm long.  About 2 million seeds/kg.

Distribution

Native to:
Africa:  Angola, Botswana, Democratic Republic of Congo (Zaire-Shaba), Ethiopia, Kenya, Malawi, Mozambique, Namibia, Somalia, South Africa (Free State, Mpumalanga, Gauteng, North West, Limpopo), Tanzania, Uganda, Zambia, Zimbabwe.
Widespread in native environment, occurring in grassland, savannah or woodland, in tall and short grass associations.  Common in disturbed areas and abandoned cultivations.

Introduced as a pasture grass throughout the tropics.  Now commercially planted in Australia and southeast Asia.

Uses/applications

Long-term pasture, cut-and-carry, hay , ground cover for erosion protection and nematode control in bananas.

Ecology

Soil requirements

In the wild, found mainly on sandy/sandy loam soils, but also on red, and heavy black, seasonally waterlogged soils;  pH from acid to alkaline.  (see 'Cultivars' for cultivation soils.)  Survives under low to moderate fertility conditions, but responds to improved fertility.

Moisture

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Occurs naturally in areas with annual rainfall from 400-1,700 mm, either bimodal, or over 5-6 months with a prolonged dry season.  Very drought tolerant.  Mostly, does not tolerate waterlogging , although tufted type found on heavy black, seasonally waterlogged soils.

Temperature

From 2ºN to 24ºS.  Largely warm season growth, although moderate production either side of summer.  Grows at altitudes from 0 to >2,000 m asl .  Although tops are killed, survives frost, recovering from tufts and plantlets along the stolons.

Light

Generally not considered shade tolerant.

Reproductive development

Appears to be a quantitative long day plant.  Flowering commences soon after resumption of growth after winter or the dry season, and reaching a peak in mid-summer.

Defoliation

Very tolerant of grazing or cutting.  However, extreme palatability of some provenances can lead to decline in heavily grazed pastures.

Fire

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Recovery after fire better than D. eriantha (pangola grass ), although some ecotypes better than others.

Agronomy

Establishment

Freshly harvested seed is dormant, with ecotypes from high rainfall areas having short dormancy and ecotypes from low rainfall having extended dormancy.  Germination improves with >5 months of storage.  Experimentally, dormancy can be broken by removing the palea and lemma from around the caryopsis .  Seed is sown at 1-4 kg/ha depending on seedbed preparation and proposed application.

Fertiliser

On less fertile soils, seed should be sown with 10-20 kg/ha P, with annual maintenance applications of 5-10 kg/ha P.  Potassium may be required on some soils.  Needs at least 100 kg/ha/yr N to be productive in less fertile soils.

Compatibility (with other species)

Not as competitive as many of the tropical grasses, but sward-forming types may suppress legume seedling recruitment.

Companion species

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Pests and diseases

Generally good field resistance to rust (Puccinia oahuensis).  Adults and larvae of crab grass leaf beetle (Lema rufotincta) can severely damage seedlings and young leaf tissue during the early part of the wet season in northern Australia.  Natural predators usually quickly control this small beetle.  Leaf-cutting ant (Acromyrmex landolti) is attracted to D. milanjiana in Paraguay (more so than to Brachiaria brizantha or Cenchrus ciliaris ).

Ability to spread

Spreads gradually by stolons.  Soil disturbance is necessary in spread by seed.

Weed potential

Recorded as a weed in cultivations in Africa.

Feeding value

Nutritive value

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Depends on soils fertility and age of growth.  CP from 8 to >12%, and average IVDMD in 4- and 8-week old material from 64-67%.  CP digestibility in hay about 55%.  Green leaf recorded at  2.11% N, 0.28% P, 0.16% S, and 0.84% Ca in the dry matter.

Palatability/acceptability

Mostly an extremely palatable species, with some provenances more palatable than others.  'Jarra' and 'Strickland' both considered more palatable than 'Arnhem' and Digitaria eriantha (pangola).  Well eaten by all classes of stock, including the wild fauna of Africa, and magpie geese and wallabies in Australia.

Toxicity

No record of toxicity.

Production potential

Dry matter

Yields up to 34 t/ha/yr DM, depending on fertilizer application and growing conditions.  More commonly 10-20 t/ha/yr DM.

Animal production

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No information available.

Genetics/breeding

Cross-pollinating, 2n = 18, 36, 54.

Seed production

In some environments, it is possible to obtain 3 harvests/yr.  In the Northern Territory of Australia (southern hemisphere, tropics), 'Arnhem' can produce crops in November/December, late January/February and April, each producing about 100 kg/ha seed.  In the same environment, 'Strickland' produces a light December crop, followed by up to 100 kg/ha seed in February, and a further 40-50 kg/ha in April/May.  In north Queensland, 'Jarra' also flowers throughout the growing season, with a distinct peak in mid-summer.  A single harvest from this flowering can yield 200 kg/ha seed, and up to 250 kg/ha in January/February.  Similarly with 'Strickland' in southern Queensland (subtropics), using a clearing cut and fertilising with 100-150 kg/ha N in November/early December, seed yields of 200-250 kg/ha can be obtained.  Initial attempts to obtain 2 crops per season resulted in light crops totalling less than the mid-season crop.  Yields are lower in less favourable moisture and fertility conditions, and may be more of the order of 80-100 kg/ha.  Large areas tend to produce more seed than small plots, possibly due to improved pollination opportunities.  Seed crops can be harvested with a beater harvester, a brush harvester or a conventional header, usually when about 10% of mature seed has been shed.

Herbicide effects

Susceptible to glyphosate.

Strengths

  • Very palatable.
  • Drought-hardy.
  • No serious disease.
  • Grows on most soils.

Limitations

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  • Intolerant of poor drainage.
  • Flowers throughout the growing season , becoming stemmy.
  • Frost tender.

Other comments

  

Selected references

Bogdan, A.V. (1977) Tropical Pasture and Fodder Plants (Grasses and Legumes). pp. 123-124. (Longman: London and New York).
Gibbs Russell, G.E., Watson, L., Koekemoer, M., Smook, L., Barker, N.P., Anderson, H.M. and Dallwitz, M.J. (1990) `Grasses of Southern Africa.' Memoirs of the Botanical Survey of South Africa No. 58 . (Botanical Research Institute: Pretoria.).
Hacker, J.B. and Wong, C.C. (1992) Digitaria milanjiana (Rendle) Stapf. In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages. pp. 123-124. (Pudoc Scientific Publishers, Wageningen, the Netherlands).

 

Internet links

Cultivars

Cultivars

Country/date released

Details

'Jarra'
(CPI 59745)
Australia (1991) From Malawi (16ºS, 61 m asl, rainfall 700 mm, well drained loam, pH 7.5).  Stoloniferous.  Foliage to 1 m and flowering stems to 1.8 m high.  Leaves broad, dark green and purple, somewhat hairy, superficially resembling the annual , D. bicornis.  Suited to areas receiving annual rainfall of over 1,100 mm.  Can persist with 900 mm of annual rainfall but with reduced productivity.  Successful on a range of soil types from coarse granitic sandy loams, alluvial loams, and shallow solodics, to a euchrozem.  Better than 'Strickland' in higher rainfall areas, although more sensitive to waterlogging .  Resistant to burrowing nematode (Radopholus similis), a serious economic pest of bananas, where 'Jarra' is used as a ground cover between rotations.  A grass rotation lasting 2 years with no weed hosts can break the burrowing nematode cycle.
'Strickland'
(CPI 40700, PI 299792)
Australia (1995) Held by USDA as D. eriantha , (formerly Digitaria setivalva).  From Botswana (Lake N'Gami, Kalahari;  20ºS, 940 m asl, rainfall 465 mm).  Stoloniferous.  Foliage to 1 m and flowering stems to 1.5 m high.  Leaves grey-green.  Suited to areas receiving annual rainfall >900 mm, although persists with less.  Very drought tolerant;  better than 'Jarra'.  Withstands some waterlogging but not prolonged flooding.  Successful on sands to clays, including solodics, lithosols, yellow earths, red earths and sandy red earths.
'Arnhem'
(CPI 59749)
Australia (1996) Formerly classified as D. swynnertonii.  From Mozambique (20ºS; 45 m asl, rainfall 1,200 mm).  Tussock habit (no stolons);  leaves green, glabrous.  Foliage to 70 cm and flowering stems to 1.5 m.  Suited to areas receiving annual rainfall of over 1,100 mm.  It will grow well on a wide range of soil types including lithosols, red earths, sandy red earths, yellow earths and seasonally flooded solodic soils.  Can withstand up to 3 months waterlogging.  Tolerant of flooding and occasional burning.  Drought tolerant.  Less palatable than Digitaria eriantha (pangola), 'Jarra' or 'Strickland'.  Tolerant of heavy stocking.

Promising accessions

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Promising accessions

Country

Details

CPI 41192 (PI 299782) Australia (Queensland) Introduced as D. polevansii from USA.  Also referred to as D. seriata and D. eriantha .  Similar to 'Strickland'.  High yielding with good persistence in the humid and dry subtropics.
CPI 59752 Australia (Queensland) Held in gene bank as D. natalensis but similar in appearance and behaviour to D. milanjiana .  From Zimbabwe (16ºS, 545 m asl, rainfall 650 mm).  Robust, persistent, leafy, broad-leafed, to 1.8 m at maturity.  Develops strong stolons, also forms below ground rhizomes.  Extremely palatable.  Possibly better suited to rainfall above 900 mm, but persists at less.
CPI 59755 Australia (Queensland) From Victoria Falls, Zimbabwe (18ºS, 818 m asl, rainfall 650 mm).  Leafy, broad-leafed extremely palatable, persistent type.  Possibly better suited to rainfall above 900 mm, but persists at less.
CPI 59761 Australia (Queensland) From Zimbabwe (22ºS, 500 m asl, rainfall 450 mm).  Rated "good dense sward , palatable" in seasonally dry tropics.
CPI 59777 Australia (Queensland) Introduced as D. pentzii .  From Victoria Falls, Zimbabwe (18ºS, 818 m asl, rainfall 650 mm).  Leafy, broad-leafed extremely palatable, persistent type, similar to CPI 59755 but more stoloniferous.  Possibly better suited to rainfall above 900 mm, but persists at less.
CPI 59786 Australia (Queensland) From Zimbabwe (21ºS, 545 m asl, rainfall 500 mm).  Collected as D. pentzii .  Rated "exceptional" in dry upland tropics, and "best" in sub-humid lowlands at 24ºS.
CPI 59829 Australia (Queensland) From South Africa (23ºS, 970 m asl, rainfall 425 mm).  Collected as D. setivalva.  Rated "excellent" in dry upland tropics.
S57 (= GL42) Paraguay From Botswana (rainfall 550 mm).  Persistent under dry conditions in sandy soil.
T8 (=GL40), T9 (= GL21), T10 (= GL46), T11 (= GL24), S95 (= GL18) Paraguay From Botswana (rainfall between 450 and 600 mm).  Non-stoloniferous (except S95 that forms some stolons), but producing many rhizomes, forming dense mats under strong grazing.  All produce viable seed.
T1 (= CPI 125658) Paraguay From Bulawayo, Zimbabwe (19.31ºS, 1,200 m asl, rainfall 600 mm).  Stoloniferous and rhizomatous ;  prolific seed producer.