Green panic (Panicum maximum var. trichoglume), is a tufted, summer-growing perennial species of guinea grass. It persists best on high fertility, friable, softwood scrub loams and light clays. It dislikes sand, hard setting soils and heavy-cracking black clays, and is intolerant of waterlogging. It needs a minimum of 600 mm annual rainfall.
Green panic is very palatable to stock. Having some shade tolerance it is often found growing under trees and shrubs. It has moderate drought tolerance and a remarkable ability to yield a 'green pick' if mild weather follows winter rainfall.
In drier areas, its persistence is limited to short-rotation pasture leys or survival in the protection of shade trees. In wetter areas, it makes good permanent pasture (either as a pure stand or combined with lucerne and other legumes). If necessary, the grass will survive burning.
Petrie is the only cultivar of green panic.
When to sow
Green panic may be planted from October to late February. If planting in early spring be aware that even though evaporation is lower, weed competition at this time can be detrimental to young pasture seedlings. Mid-summer planting (January to February), when there is a higher probability of receiving consecutive rain days, has the best chance of success. It is also the most likely period to receive good follow-up rain after planting. In cooler areas seedlings must be established before the onset of frost.
Best results are obtained from a prepared seedbed that has been fallowed for moisture and nitrogen accumulation and weed control. The surface 50 mm should be fine and firm. The odds of establishing a pasture improve if the sub-soil moisture is good at sowing. Depending on soil depth aim for a minimum of 40 cm of wet soil under the seedbed. Rougher seedbeds with less soil disturbance need a higher seeding rate and give less reliable results. The ash left after a scrub burn can make a good seedbed.
Sow 2-3 kg/ha of good quality seed.
Legumes for green panic pasture
Sowing an adapted legume with the grass will add nitrogen to the pasture system and will help improve both the quality of grazing and the fertility of the soil. Lucerne (1 kg/ha) and medics (1-2 kg/ha) can be oversown in autumn after the grass has established.
Sowing method and sowing depth
Seed may be broadcast onto the top of the seedbed or drilled into the dry seedbed with precision planters. The small seed should be within the first 5-10 mm of the soil surface.
Broadcasting seed into the ash soon after a scrub burn has also been successful.
Seed soil contact may be improved on non-crusting soils by rollers. On most soils presswheels will firm the soil around the seed. Be careful if harrowing after sowing that the small pasture seed is not being buried by more than 5-10 mm of soil or the shoot might not have the energy to emerge.
Sowing dry ensures that pasture seed is in the right position to take advantage of the next rainfall to start germination. The seed must maintain close contact with wet soil for about three days to establish a seedling. Sub-soil moisture will sustain the seedling until follow-up rainfall occurs. This rain will also promote the development of secondary roots. This allows the crown of the establishing grass to develop.
Pasture seed in the bottom of shallow tine furrows or small depressions in more roughly prepared seedbeds are more likely to establish seedlings because they accumulate water and stay wetter for longer after rain.
A soil analysis will indicate major nutrient deficiencies before planting.
Green panic likes good soil fertility and on older cultivated soils responds well to added nitrogen, especially of legume origin, and to sulfur and phosphorus. A pale yellow-green colour indicates a nitrogen or sulfur deficiency.
A good fallow before planting should release enough nitrogen to allow the grass to establish. Phosphorus deficiency is unlikely to be a problem on clay soils, but apply superphosphate, which also supplies sulfur, to the seedbed if a soil analysis or past history has indicated a deficiency.
A vigorous legume component will be the best source of nitrogen for the grass in an established dryland pasture as it is usually uneconomic to apply nitrogen fertiliser. Renovation of mature pasture that is showing signs of decline will release nitrogen to rejuvenate the stand for a short time.
Green panic and legumes also require sulfur and phosphorus for good production. Top dress, either in early spring or early autumn, with 125 kg of superphosphate, if the soil phosphorus is low. If only sulfur is deficient, apply gypsum (0.5 t/ha) or elemental sulfur (60 kg/ha) every 2-3 years.
Weeds can compete seriously with young pasture seedlings. Good cultural practices in the season before sowing (pre-cropping or fallow) will help reduce the weed seed population in the prepared pasture seedbed.
After establishment most broadleaved weeds should be suppressed by a dense vigorous growth of pasture. Although it is generally impractical to use herbicides for broadleaved weed control, a number are registered for that purpose. Care should be taken in their selection to avoid killing useful pasture legumes. For further information on herbicide selection consult your company agronomist.
Weed control in young pasture is difficult. Slashing or light grazing may reduce weed competition.
Pest and disease
Armyworm and white grubs can sometimes cause damage to the pasture.
The successful establishment of a pasture will depend on grazing management in the first year. Do not graze until follow-up rainfall allows seedlings to develop crowns, a strong root system and set some seed, then graze lightly for short periods.
Green panic is very palatable and is usually grazed preferentially in a mixed sward. As animal production is better from short to medium growth than from older 'stemmy' material, graze either with a set stocking rate or rotationally graze the forage at the right stage of maturity. Spelling the pasture in late summer will allow it to set seed and so persist for longer.
If there is lucerne in the pasture, graze rotationally (e.g. graze 1-2 weeks and spell for 4-8 weeks). Moderate grazing in autumn will encourage the growth of annual winter legume.
Green panic or panic-legume pasture can be made into good hay if cut when the grass is coming into flower.
Green panic can be either direct headed or swathed. The seed is ripe when its colour changes from green to yellow. Harvest timing is important as the seed ripens unevenly and can fall quickly when ripe.
Other related species
Gatton panic (Panicum cv. Gatton) is a medium-height variety of guinea grass: a tufted, summer-growing perennial similar to green panic and just as palatable. It has similar management requirements as green panic, but it does not exhibit the same shade tolerance. Gatton panic will persist on soils of lower fertility than green panic.
Gatton panic has longer, broader, hairless green leaves as distinct from green panic's light green foliage with hairy lower leaf blades and leaf sheaths.