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Panicum maximum var. trichoglume (K. Schum.) C.E. Hibberd |
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Graminae Green panic (Australia), castilla (Peru), slender Guinea grass (Kenya). A tufted, tall, summer-growing perennial, differing from common Guinea grass in being smaller and less robust, in having finer stems and leaves, and in having the glumes of its spikelets covered with fine hairs. Its six-to eight-noded stems normally grow to 1 m, with crowns up to 15-30 cm in diameter. Compared with P. maximum cv. Gatton, the lower surface of the leaves and the leaf-sheaths are sparsely hirsute or villose rather than finely pubescent; the midrib of its leaf is less prominent and more hirsute; its leaf margins are less scabrid and its ligule is a ring of long downy hairs, rather than short straight bristles (Barnard, 1972). Native to Africa, common in India and introduced to Australia. Good growth in early spring, better than buffer and Rhodes, continuing through summer and autumn. Leaf production dwindles with the onset of flowering in early summer. Sea-level to 2 000 m. It has a wide range, between 650 and 1 780 mm in Queensland, but is not as well suited to high coastal rainfall as common Guinea; it does better a little inland from the coast. It does not thrive at over 2 000 mm annual rainfall. Moderate (Tsiung, 1976), more tolerant than Rhodes grass, less than buffer. It does best on deep scrub loams of high fertility, but performs well on basaltic uplands of prairie and black soils and sandy loams of reasonable fertility. Tolerates soil pH from 5.0-8.0. Deep sands are unsuitable. If allowed to seed it will gradually extend its population by new seedlings, especially on the edge of scrubs and near watercourses.Land preparation for establishment A fine seed-bed or ashes needed. Either drill into a prepared seed-bed or broadcast in ashes from land or air. Drilling in a contour furrow with press wheels gives an excellent stand (Wilson, 1978). Sowing at 1 cm depth in a companion crop of lucerne, oats or wheat gives good results (Bott, 1978). Sow no deeper than 1 cm and cover lightly. A "Triad" seed planter applying a narrow band of gypsum over the row to prevent soil crusting is successful (Bott, 1978). When drilling or sowing from the air, sow during the rainy season and one week after a scrub burn at 4 kg/ha. Two plantings, one in spring and one in midsummer, may give a more reliable farm sequence. 1 225 000 (Queensland). Green and Gatton panics showed a high tolerance to post-emergence spray of atrazine at 1-2 kg/ha of 80 percent product, which killed seedlings of Salvia reftexa (Wilson, 1978). Green panic was unaffected by the application of 1.68-2.24 kg AI/ha of Fenoprop (2-(2,4,5-trichlorphenoxy) propionic acid), as the propylene glycol ether ester (PGEE) with 0.1 percent non- ionic wetter which exerted satisfactory control of chickweed (Drymaria cordata) in the Panicum maximum var. trichoglume/Neonotonia wightii pasture on the Atherton Tableland, Queensland (Hawton, Quinlan & Shaw, 1975). It has good seedling vigour.Vigour of growth and growth rhythm About 80 percent of the production occurs in the summer months, October to March, in north Queensland (Gartner, 1966). Green panic will stand reasonable, but not heavy, defoliation. Stock at reasonable intensity and then allow about six weeks for the pasture to recover before the next grazing. If in association with lucerne, stock fairly heavily for one week at each grazing and allow the lucerne to recover. Continuous grazing of the lucerne will cause it to die out. Allow the green panic to set seed at least every two years. It does not stand hot burning, and burning should only occur where woody weeds need controlling (Skovlin, 1971).Dry-matter and green-matter yields At Koronivia, Fiji, a yield of 26 781 kg/ha was obtained over an 11-month period (Roberts, 1970a, b). Up to 10 000 kg DM/ha has been obtained in south-east Queensland during a growing season. Henzell (1976) increased dry matter yield from 7 250 kg/ha to 13 130 kg/ha with the application of 167 kg N/ha at Narayen, Queensland.Suitability for hay and silage It makes good hay and silage when cut at flowering stage. A green panic-siratro mixture is often used (Kelly, 1972).Value as a standover or deferred feed It is a useful standover feed. Rare cases of unconfirmed toxicity have been reported, but its long use for grazing makes the risk of toxicity very small (Everist, 1974). In Cuba, 327 kg/ha were harvested from two cuts, with 60 cm spacing and 300 kg NPK fertilizer (Paretas et al., 1972). Only one cultivar is registered, cv. Petrie, the characteristics of which are being described. It was named after A.A. Petrie of 'Madoora', Gayndah, Queensland, who first grew the grass commercially. No major diseases are encountered. Its ability to grow in shade, its palatability, and its ability to combine with other grasses and legumes. Its uneven seed setting and its lack of persistence in poor soils without adequate fertilizer.Optimum temperature for growth Ludlow and Wilson (1970b) found dry-matter production was 3.47 times greater for cv. Embu, 21.4 times greater for cv. Hamil, 15 times greater for common Guinea grass and 9.76 times greater for cv. Gatton at 30°C than at 20°C..Minimum temperature for growth It responds quickly to mild weather in winter. Only slightly tolerant more susceptible than Rhodes grass. About 30°N and S. One of the outstanding features of green panic is its ability to grow in partial shade, which also protects it from frost. It grows right up to tree trunks. In its normal environment it can successfully suppress weeds.Maximum germination and quality required for sale 20 percent germination and 70 percent purity are required in Queensland, Australia. No major pests occur. It is extremely palatable.Chemical analysis and digestibility It has a high nutritive value even when mature and frosted (Milford, 1960a, b). Forest fringes. It is killed by a few days of saturated soil and is unsuitable for intensive irrigation. It responds fairly well to nitrogen on poor soils and will gradually disappear when fertility declines. Linear responses to nitrogen up to 440 kg/ha per year were recorded by Gartner (1966) on the Atherton Tableland, Queensland, but the most efficient response by green panic was at 55 kg N/ha. Production of green panic, at 154 kg/ha, is of the order of that produced in combination with the legume Neonotonia wightii cv. Tinaroo. Phosphorus, nitrogen and sulphur are generally needed on the Darling Downs' black clay, Queensland (Swann, 1973). A pale leaf colour may be due to nitrogen or sulphur deficiency. Regular use of single superphosphate will supply the sulphur requirement (Delaney, 1975). The critical value of phosphorus as a percentage of the dry matter at the immediate pre-flowering stage is 0.19.Compatibility with other grasses and legumes It combines very well with the tropical legumes suited to its environment, and with lucerne (Medicago saliva), especially on basaltic loamy soils and deep sandy loams in Queensland. It grows well with siratro (Macroptilium atropurpureum), Neonotonia wightii and several other legumes in Fiji and Queensland. It is compatible with buffer grass (Cenchrus ciliaris), and Nandi setaria but not with Rhodes grass. Sorghum almum can be a temporary companion grass in new sowings. P. maximum is a pseudogamous apomict.Seed production and harvesting It flowers from early summer to late autumn. Wait until the ripest seed has started to shed to ensure ripe seed. Seed does not ripen evenly and shatters badly; early harvesting may collect too much immature seed, and late harvests will miss seed which has shed. Harvest with an autoheader when 5- 10 percent seed has shattered. Dry the seed thoroughly before storing or it may overheat. Seed may have to be stored for some time to reach satisfactory germination standards. Given reasonable climatic conditions and management, a carrying capacity of better than one beast to two hectares can be anticipated for a green panic/legume pasture, or from a nitrogen-fertilized stand of pure green panic. With beef cattle, an annual live-weight gain of 140 kg per head could be expected with a pure green panic pasture, or 180 kg with a legume included with it (Delaney, 1975). At Narayen, Queensland, green panic pastures fertilized with 300 kg N/ha per year produced an average live-weight gain in steers of 180 kg per head per year of first-grade carcass, compared with 146 kg per head per year of second-grade carcass from unfertilized or superphosphate-fertilized pastures (Silvey, 1977a, b). Under irrigation, in conjunction with Leucaena leucocephala, on the island of Kauai, Hawaii, the pasture produced 9 770 kg milk and 400 kg beef per hectare per year (Plucknett, 1970).At Kairi in the Atherton Tableland (lat. 17°14'S, 700 m altitude and 1 248 mm rainfall, of which 830 mm occurs from January to April) from green panic/Tinaroo glycine pastures, Jersey cows produced 2 480 kg milk and 114 kg butterfat per lactation and Friesian cows 4 100 kg milk and 137 kg butterfat (Cowan, Byford & Stobbs, 1975). These yields compare favourably with those recorded from other tropical dairying areas (Colman & Holder, 1968; Stobbs, 1971).P Grass genera of the world: Information about botany, ecology etc. of the panicum genus; links to photographs of different species Delaney, 1975; Young, Fox & Burns, 1959. It has a long period of dormancy, reaching maximum viability 18 months after harvest. Because of its tussocky nature it is not specifically suited to erosion control, but it exerts some influence. It will tolerate soil pH to 8.0. |