Paspalum

Botanical name:

Paspalum dilatatum

Features

• slowly creeping, sward-forming grass
• highly tolerant of grazing
• very good late spring-early summer growth
• moderate drought tolerance
• seed heads susceptible to ergot infection.

Paspalum (or Dallis grass) is a summer-active perennial grass native to the humid sub-tropics of southern Brazil, Argentina and Uruguay. It is now widespread in many areas of the world and under suitable conditions is capable of very high production.

Paspalum was introduced into Australia in the late 19th century and was one of the first warm season grasses to be widely cultivated. In WA it was first sown in the irrigation areas and has now naturalised in disturbed moist areas, along irrigation channels and in lawns from Kalbarri to Albany. It can be an invasive weed of claypans.

Paspalum has relatively small seeds (570-700,000/kg) and should be sown no more than 10 mm deep. The suggested sowing rate is 2-5 kg/ha when sown alone. In WA, paspalum is dormant in winter and grows actively from October to May, providing soil moisture is non-limiting. It grows rapidly in late spring and early summer and then opportunistically over summer if moisture is available. It will run to seed rapidly in summer and needs to be heavily grazed to prevent seeding.

Palatability drops markedly in rank or old growth. Paspalum can withstand heavy grazing due to its rhizomatous growth habit, but for high production it should not be grazed below 5-7 cm. Paspalum pastures can become sod-bound, so periodic renovation to maintain productivity and retain the annual clover content is recommended. The pasture can be cultivated in autumn and then if required, re-sown with temperate species to provide the cool season growth.

Description

• tufted perennial grass with short rhizomes
• leaves are 7-40 cm long, flat and hairless with a distinct
• mid-rib and often wrinkled along the leaf margins
• seed heads have 4-6 lateral spikes on stems 0.6-1.5 m tall
• spikes are usually 4-10 cm long with a double row of spikelets along one side.

Seed heads can be infected with ergot (Claviceps paspali) a dark-coloured, sticky fungus that can poison stock. Animals grazing affected pastures can develop ‘paspalum staggers’. Poisoned animals that are removed from the infected pasture at an early stage can recover within a few days. To control the disease, graze hard in summer to prevent seeding, or mow to remove the seed heads.

Paspalum has moderate drought tolerance, so is not confined to irrigated pastures. The role for paspalum in WA is mainly for soils that remain moist in summer and in southern coastal districts, either as part of a pasture mix or sown alone.

Cultivars

‘Common’ paspalum is the only type available.

Seedhead and seeds

Soil–climate adaptation

Rainfall (est.): >600 mm plus summer moist sites

Drought tolerance: Moderate

Frost tolerance: Moderate, underground root-stocks allow it to recover from frosts

Soil type: Grows on sands to clays, but prefers fertile soils

Soil fertility requirements: Moderate

Soil pHCa : >4.3 (est.)

Aluminium tolerance: Unknown

Waterlogging tolerance: Moderate to high

Salt tolerance: Nil

Ability to spread naturally: Slowly by rhizomes and seed

Nutritive value

DMD: 56.7-58.4% (monthly cuts), 68.1% (leaf), 59.8% (stem)

Crude protein: Av. 10.1% (range 5.7-12.9%)