|
Panicum antidotale Retz. |
 |
Graminae Blue panic (Australia, United States), giant panic (Australia), perennial Sudan grass (United States), bansi (India). Tufted perennial up to 150 cm high, glabrous but with woolly bud scales at the base. Panicle up to 30 cm long, dense, with 3 mm-long acute spikelets, the lower glume half as long as the spikelet. Glumes with broad, membranous margins (Napper, 1965). It has short, thick, bulbous rhizomes and deep roots and blue-green leaves. Native to India, now introduced to many countries as a pasture grass. Cultivated in some countries. Summer. It is best adapted to areas of summer rainfall where annual precipitation is 500-750 mm, or irrigated land. It can grow in areas with less than 130 mm of rain in Rajasthan, India. It has a high degree of drought tolerance, but will respond readily to summer storms. It has a very deep root system. Grows best on fertile soils and is more demanding than buffer grass. It prefers heavy loams or dark clay soils high in lime and does not do well on sandy soils that are acid or low in organic matter (Trew, 1954). There is a very slow spread from fallen seed. Land preparation for establishment A fine seed-bed is preferable, either from mechanical preparation by ploughing or harrowing, or by scrub burning and sowing in the ashes. It is propagated by seed, either drilled in rows or broadcast. In India it is sown in rows 45 cm apart. When drilled, cover no more than 1 cm; when broadcast, sow on surface and, if possible, give a light cover. In ashes the burial from broadcasting is sufficient. In the Sudan it germinates from a depth of 5 cm (Abd-El-Rahman & El-Monayeri, 1967). Sow just before the expected rainy season at 6-7 kg/ha broadcast, or 1.25 kg/ha in rows 1 m apart. 1 299 000 (Queensland); 1 445 000 (United States). It can be sprayed with 2,4-D to control broad-leaved weeds. The seed germinates well, but plant development is slow for the first six to eight weeks (Barnard, 1969). Vigour of growth and growth rhythm It makes strong growth earlier in spring than buffer grass and continues strong through the summer, but becomes woody at maturity. It cannot withstand heavy, close grazing. It needs to be utilized before running to seed, as the flowering stalks become hard and woody. Cutting at 20-day intervals to 10 cm in a wet year, and at 30-day intervals to a height of 15 cm in a normal year, gave highest yields in Rajasthan, India (Dabadghao, Roy & Marwaha, 1973). Blue panic is ready to graze when well established, and needs heavy intermittent grazing to keep it at a nutritious stage. It requires 25-30 cm of stubble left after cutting or grazing. Stems rapidly become hard and woody and should be grazed or cut before flowering. The grass often grows too fast for the cattle; surplus should be made into hay. The stemmy material left at grazing should be removed by mowing or slashing to allow fresh growth to arise from the base. About 35 kg/ha of nitrogen can be applied after every grazing. It is resistant to fire. Dry-matter and green-matter yields In Gujarat, India, 4 733 kg green matter per hectare were harvested (Srinivasan, Bonde & Tejwani, 1962). From 2 500 to 6 000 kg/ha of hay can be anticipated. Under irrigation in Iowa, United States, it yielded 4 780 kg/ha per year over three years (Trew, 1954). Suitability for hay and silage It makes good hay and fair silage if cut at the flowering or milk stage (Trew, 1954). Value as a standover or deferred feed The coarse woody stem is of little value, but a few leafy side shoots can provide a little grazing. Reported to have a high oxalate content (over 4 percent) in Queensland (Mathews & Sutherland, 1952). The seed ripens unevenly and a lot of it shatters. To obtain more seed, it can be cut with a reaper and binder before shattering and subsequently threshed. Direct heading will give a low yield. It is hand harvested in India. Rain grown yields reach 100-160 kg/ha, irrigated 250-600 kg/ha. There are several varieties recognized in the United States. Cultivar A- 130 was derived from seed introduced from Australia. Strain 341 is recommended for use under arid conditions in western Rajasthan, India (Prasad & Singh, 1973). It has no major diseases. Its palatability, deep-rootedness and drought tolerance. The woody stems of mature plants and its uneven seed setting and seed shattering. Susceptible to frost damage, but will retain some greenness in mild winters. About 35°N. It will grow in partial shade around buildings, but prefers full sunlight. Maximum germination and quality required for sale 50 percent germinable seeds, 80 percent purity (Queensland). Germinate at 20-30°C in water. There are no major pests. Young growth up to flowering is extremely palatable, but it should not be allowed to become too coarse. Chemical analysis and digestibility Göhl (1975) records fresh early pasture with 18.8 percent crude protein in the dry matter, and fresh mature material with as low as 8.4 percent crude protein in Pakistan. In India figures of 7.3 percent crude protein, 40.5 percent crude fibre, 7.9 percent ash, 1.2 percent ether extract and 43.1 percent nitrogen-free extract were recorded (Sen & Ray, 1964). Sand dunes and dry river beds in north-west Pakistan, Afghanistan and Iran. It will tolerate temporary flooding. Responds markedly to nitrogen, but a basic NPK fertilizer may be needed according to soil composition. At Jodhpur, India, application of 30 kg N + 30 kg P2O5 + 20 kg K/ha increased yields by 273 percent (Singh & Chatterjee, 1968). 2n= 18, 36 (Fedorov, 1974). Reproduction is sexual. It is sometimes used in native medicine, which probably prompted the specific name "antidotale". A useful summer forage. It has given good cattle production in burnt Acacia cambagei country along with Cenchrus ciliaris in Queensland in an annual rainfall regime of 425-500 mm with summer dominance. There is some post-harvest dormancy for a maximum of two years' germination of 80 percent at five to eight years, declining to 25 percent at 11 years and 3 percent at 13 years (Myers, 1940). It is used extensively for erosion control in the flood plains of the United States, mainly to protect against wind erosion, and is sown in rows at right angles to the prevailing wind. It is not very effective for control of water erosion (Srinivasan, Bonde & Tejwani, 1962). It has some tolerance to salinity but more to alkalinity caused by sodium and magnesium than to the chlorides (Ryan, Miyamoto & Stroehlein, 1975).
Trew, 1954. |