Paspalum nicorae


Scientific name

Synonyms

Paspalum plicatulum Michx. var. arenarium Arechav.
Paspalum arenicolum Herter

Family/tribe

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

Common names

brunswick grass (USA, Australia).

Morphological description

"A perennial with long, deep and vigorous rhizomes.  Culms erect, generally less than 40 cm tall, with basal leaves and short internodes.  Leaves erect, narrow, grey-green, sheath glabrous, ligule 0.5-1 mm;  leaf blade 10-20 cm long and 2-3 mm broad with sparse hairs underneath.  Inflorescence grey-green, generally with 2-4 racemes, 2-4 cm long;  spikelets ovoid-elliptical, 2.4-2.8 mm long and 1.5 mm broad;  sterile lemma usually transversely wrinkled;  glume with very short, fine hairs visible only under magnification;  caryopsis dark chestnut brown and pronouncedly convex." (Barreto, 1956).
Examination of further material broadens this description:
Degree of rhizome development varies from shortly rhizomatous, almost tufted, to vigorous rhizomes extending >25 cm/yr;  foliage 25-50 (-60) cm tall, leaves pale green to grey green, 20-30 cm long, 3-9 mm wide, varying with genotype.  Inflorescence comprising 2-5 racemes 2-7 cm long.  Seed grey-green in glume .  Has rhizomes (mostly in top 10 cm of soil) which spread below the soil surface, unlike P. notatum which has stolons which spread along the soil surface.  450,000 seeds/kg.

Distribution

Native to:
South America:  Argentina (north), Brazil (south), Paraguay, Uruguay.

Naturalised in:
USA (southeast), Australia (Qld, NSW).

Uses/applications

Used for permanent pasture in the subtropics, and may have application for hay and silage.  Ground cover (soil conservation) under trees, stabilisation of waterways, traffic areas.  Not suited to short-term pasture due to difficulty of control.

Ecology

Soil requirements

P. nicorae is found on sandy soils of the littoral (coastal) and Central Depression in Rio Grande del Sur (Rio Grande do Sul), Brazil, granitic sands in Cordoba Province of Argentina, and red sandy loams in south-east Paraguay.  While preferring sandy soils, it has also proven adapted to light to medium clays, and even hard-setting sandy clay loams, provided internal drainage is fair to good and moisture is adequate.  Although it is often found on infertile soils in native and naturalised situations, it responds to improved fertility.  It prefers acid to slightly alkaline soils with a pH <8.

Moisture

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Rainfall at collection sites varies from about 800 mm to 1,500 mm/yr, and in cultivation, various genotypes have been successful over a similar range, and to as low as 700 mm/yr.  P. nicorae is drought tolerant.  It survives short periods of flooding, but does not tolerate permanent waterlogging .

Temperature

P. nicorae extends from about 25ºS in Paraguay to 35ºS in Uruguay and Argentina, and from 65ºW in Argentina to 50ºW in Brazil.  This distribution may extend to 21ºS in Brazil (Campanha).  Most of the more attractive forage types come from Rio Grande do Sul in Brazil, between about 29º and 30ºS.  Altitudes are mostly from near sea level to 500 m asl.  Average annual temperatures over its distribution range from about 16º in Uruguay to 23ºC in Brazil, and frosts are experienced.  The species has become naturalised in areas experiencing temperatures as low as -15ºC (USA) and recording an average of 35 days with screen temperature <0ºC each year (Australia).  The foliage has frost tolerance comparable with that of Pennisetum clandestinum , but is burnt off by severe frost and makes no further growth during the winter when grown in cool climates.  Deep rhizomes are protected from frost by the soil, and even severely frosted plants recover quickly with the advent of warmer, moist conditions.  The plant has good cool season growth, producing about 50% more dry matter than Pennisetum clandestinum during the 6 coolest (also driest) months at 27º S.  Although vegetative growth begins in spring and continues until autumn, over 80% of the forage is produced during the 6 warmer, moister months.

Light

Has moderate shade tolerance, growing under pine trees and eucalypts.

Reproductive development

Most lines commence flowering in summer in the subtropics (June in the northern hemisphere, December in southern hemisphere) and continue flowering for about four months.  Flowering terminates with shortening days and cooler temperatures.  Foliage production is reduced during flowering, but unlike in P. dilatatum , is still significant.  It does not flower at less than15º latitude.

Defoliation

It is extremely tolerant of defoliation, forming a low dense sward under regular mowing or continuous grazing, and regenerating well after grazing or cutting.  Yields are reduced with more regular defoliation .

Fire

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Recovers well following fire.

Agronomy

Establishment

Seed has low dormancy and can be planted relatively fresh.  It is normally sown at 2-3 kg/ha, or up to 10 kg/ha if more rapid ground cover is required.  It is best sown into a well-prepared seedbed, but can be oversown onto a herbicide treated sward if cultivation is undesirable.  Seedlings develop more rapidly than those of Paspalum notatum , with the potential to give complete cover in the first season.  Paspalum notatum may take two or three seasons to achieve the same level of cover.  In areas that are not heavily frosted, it can be planted in autumn with a light sowing of ryegrass (Lolium spp.), giving plants an early start the following spring.  In such cases, the ryegrass should be grazed regularly.

Fertiliser

It is very responsive to applied nitrogen, up to levels of 300 kg/ha/yr, depending on the soil mineral N status.  However, the greatest response generally occurs at about 100 kg/ha/yr N.  Availability of other nutrients, particularly P and K should be monitored and corrected if required.

Compatibility (with other species)

P. nicorae is very competitive, suppressing Axonopus fissifolius , Imperata cylindrica, Digitaria didactyla and tussock species such as Heteropogon contortus .  It competes effectively with Paspalum notatum .  It may have a role in suppressing invasive grasses such as Sporobolus pyramidalis and Eragrostis curvula .  It suppresses the intractable broadleaf weed, Heliotropium amplexicaule.  Production of companion legumes is also affected.  Warm season legumes such as Vigna parkeri and Aeschynomene falcata that normally combine with warm season sward grasses are suppressed by P. nicorae Arachis spp. are less affected.  Cool season species can be affected in vigorous first year stands, but once there is ecological equilibrium, productive stands of temperate legumes (e.g. Trifolium subterraneum) are maintained.

Companion species

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Grasses:  Not normally sown with other grasses, but will form associations in some situations with Digitaria eriantha , Lolium spp., and Paspalum notatum .
Legumes:  Adesmia spp., Arachis glabrata , A. pintoi , Lotus uliginosus , Medicago spp., Trifolium repens, T. subterraneum.

Pests and diseases

P. nicorae is generally not seriously affected by insects or disease.  Some genotypes are subject to ergot infection caused by Claviceps paspali.  Lepidopterous larvae such as sod webworm (Herpetogramma licarsisalis: Pyralidae) and lawn armyworm (Spodoptera mauritia: Noctuidae) often infest well fertilised, vigorously growing stands during the wet season.  African black beetle (Heteronychus arator: Scarabaeidae) is suspected of causing damage to roots and rhizomes, leading to yellowing of shoots.

Ability to spread

This ability varies with genotype.  While many accessions exhibit strong rhizome development, and spread vigorously in this way, others have limited rhizome development and tend to form broad tussocks.  Most genotypes tested seed prolifically in warm environments, hence providing the potential for significant spread.  In practice, it spreads to some extent through ingested seed, but not extensively.  As with many members of the Plicatula group, seed survival in humid conditions is limited, and development of banks of soil seed is unlikely.

Weed potential

It is difficult to control with cultivation due to rhizome survival and regeneration, although several cycles of cropping with taller species can result in control.  It is also difficult to control with herbicides.  Less palatable types have been listed as weeds, such as the low growing, rapidly maturing type that has become naturalised in northern NSW, Australia.

Feeding value

Nutritive value

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In 6-week regrowth, CP levels ranged from 7-14 (av. 10)%, P levels from 0.15-0.26 (av. 0.18)%, Ca from 0.37-0.77 (av. 0.54)%, and Mg from 0.16-0.38 (av.0.24)%.  Na levels were below the level of quantitation.  IVDMD ranged from 54-64 (av. 60)%, ADF from 34-41 (av. 38)%, and NDF from 62-70 (av. 66)%.

Palatability/acceptability

Cultivars have been selected partly on the basis of leafiness and palatability .  If regrowth is kept relatively young and leafy, (say 3-4 weeks, and no more than 6 weeks), it is readily consumed.  As with most grasses, it becomes unpalatable if not grazed frequently.  However, there are genotypes that become fibrous more rapidly than others, and are not eaten readily, even in more intensive systems.

Toxicity

No oxalate (soluble and total) was detected in 6-week old dry matter.  No problems have been recorded.

Production potential

Dry matter

In Australia, the average annual yield over two years of one accession, fertilised heavily with N and grown on a moist soil in a warm coastal environment, was 28 t/ha DM.  This is the average for grass cut at 30- and 60-day intervals at 5 cm.  Yields in less favourable environments but still with N fertilisation may be as low as 10 t/ha DM.  In the USA, when cut at various intervals and fertilised with N, the average yield ranged from 9-12 (av. 10.6) t/ha/yr DM over two years, depending on cutting frequency.

Animal production

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Average liveweight gain of 265 kg heifers stocked at 5/ha over 3 autumn months, grazing a pure stand of P. nicorae fertilised with 110 kg/ha N, was 0.6 kg/hd/day (1.3 kg/hd/day in the first month).  Reduced animal growth rates in subsequent months reflected the onset of dryer, cooler conditions, and declining grass growth rate.

Genetics/breeding

Tetraploid, 2n = 40.  Research has demonstrated that P. nicorae is a facultative apomict which reproduces by apospory and pseudogamy .  However, a small proportion of progeny from nursery-produced seed of P. nicorae growing adjacent to P. plicatulum , proved to be intermediate between the two, suggesting sexual reproduction is possible, at least in some lines.

Seed production

The species seeds freely, presenting the crop at 15-20 cm above the foliage and showing little tendency to shatter.  The stand is maintained as a low sward to maximise tiller numbers until initial inflorescences appear (about late June/early July in the northern hemisphere, late December/early January in the southern hemisphere), at which point it is mowed off and fertilised with 100 kg/ha N.  If the crop is commenced too early, excessive leaf growth develops, which can result in crop lodging.  Crops started a little later may produce slightly less seed, but present fewer problems with lodging.  Although early work suggested seed yields of 170-250 kg/ha, subsequent experience has shown that some lines can produce over 1 t/ha of clean seed each year.  Seed can be easily harvested with a scythe or mechanical header.

Herbicide effects

Mature stands are not affected by haloxyfop, triclopyr, sulfometuron methyl, metsulfuron methyl and atrazine at normal or double rates.  It is weakened by glyphosate at normal rates, but recovers within about a month.  Double normal rates of glyphosate are required for a complete kill.

Strengths

  • Widely adapted.
  • Tolerant of heavy grazing.
  • Palatable.
  • Frost tolerant.
  • Persistent ground cover.
  • No serious insect or disease problems.
  • Good seed crops.

Limitations

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  • Difficult to control with cultivation or herbicide.
  • Competes strongly with legumes.

Other comments

    

Selected references

Barreto, I.L. (1956) Las especies afines a Paspalum plicatulum en Rio Grande del Sur (Brasil). Revisita Argentina de Agronomía, 23, 53-70.
Beaty, E.R., Powell, J.D. and Lawrence, R.M. (1970) Response of brunswickgrass (Paspalum nicorae ) to N fertilization and intense clipping. Agronomy Journal, 62, 363-365.
Burson B.L. and Bennett H.W. (1970) Cytology, method of reproduction, and fertility of Brunswickgrass, Paspalum nicorae Parodi. Crop Science, 10, 184-187.
Evers, G.W. and Burson, B.L. (2004) Dallisgrass and Other Paspalum Species. In: Moser, L.E., Burson, B.L. and Sollenberger, L.E. (eds) Warm-season (C4) grasses. Agronomy Monograph 45. pp. 681-713.  (ASA, CSSA, and SSSA, Madison, WI).
Hacker, J.B., Williams, R.J., Vieritz, A.M., Cook, B.G. and Pengelly, B.C. (1999) An evaluation of a collection of Paspalum species as pasture plants for southeast Queensland.  Genetic Resources Communication No. 32.  (CSIRO Tropical Agriculture, St Lucia, Qld, Australia) ISBN 0 643 05915 6.
Strickland, R.W. (1978) The cool season production of some introduced grasses in south-east Queensland.  Tropical Grasslands, 12, 109-112.

Internet links

Cultivars

Cultivars

Country/date released

Details

'Amcorae'
(PI 202044, CPI 21370, ATF 1040)
Georgia, USA (1969) Institutional collection from Buenos Aires, Argentina.  Selected for rate of spread, height, sod density, seed-producing potential, and overall vigour.  Sod has bluish or glaucous cast (more so than most other genotypes), averaging 75 cm high at maturity;  leaves narrower (to 6 mm wide) than those of 'Doncorae'.  Produces good yield of quality seed.  Adapted in the southern coastal plain, silty uplands, and blackland prairie of south-eastern states of USA.  Potential for grazing, hay , and cover plant in waterways, and for seeding eroded areas.
'Blue Dawn'
(CPI 21370)
Queensland, Australia (1998) See 'Amcorae'.  Selected as a dual-purpose (grazing/turf) variety for use in humid and sub-humid subtropics of eastern Australia.
'Blue Eve' Queensland, Australia (1999) Spontaneous mutation.  Identified as a single plant in a 0.2 ha sward of 'Blue Dawn'.  'Blue Eve' is finer than 'Blue Dawn', with lower height, shorter internodes and leaf sheaths, narrower leaves and fewer seed heads.  Selected as a turf type.
'Doncorae'
(PI 310131, CPI 125877, ATF 1028)
Georgia, USA (1993) From Uruguaiana, Brazil (29° 45'S, 57° 04'W, 56 m asl).  Leaves to 9 mm wide.  Selected for germination, vigour, seed production and growth.  Establishes a quicker stand and is more winter hardy than other accessions tested.  A plant for establishing grass waterways, buffer strips, filter strips, field borders, water disposal areas and similar critical areas in the southern coastal plain region of the USA.

Promising accessions

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Promising accessions

Country

Details

CPI 27707 Queensland, Australia From Santa Maria, Rio Grande do Sul, Brazil,(29° 41'S, 53° 48'W, 140 m asl, rainfall c. 1,500 mm).  Vigorous, broader leafed type (similar morphologically to 'Doncorae').  Appears to be better grazed than other accessions tested.