Ryegrasses Seed

Tetraploid ryegrass has double the chromosomes, giving bigger, more palatable leaves with higher sugar and feed quality, but fewer tillers. Diploid ryegrass has finer leaves and denser tillers, so it handles hard grazing, dry spells and treading better. Tetraploid seed is larger, so it's sown at about 25–35 kg/ha versus 15–25 kg/ha for diploids. Tetraploids suit rotational grazing; diploids suit set-stocked sheep country.

If it's an annual or Italian ryegrass, that's normal: annuals last one season and Italians about two unless they reseed. Perennial ryegrass dies out when WA summers are too dry for it; it needs around 600 mm of rainfall (500 mm on the south coast) or irrigation, light grazing over summer and autumn, and good fertility. In drier country, tall fescue or a sub-tropical grass will persist better.

Annual ryegrass performs from about 350–450 mm of annual rainfall, depending on how early the variety matures. Italian and biennial types generally need 500 mm or more, with a few varieties rated from 450 mm, and perennial ryegrass around 600 mm, or 500 mm on the south coast, unless it's irrigated. In drier country, choose an early-maturing annual so it sets seed before spring dries off.

An early-sown annual or Italian ryegrass, especially a tetraploid, is hard to beat for winter feed in WA's medium and higher rainfall areas. We'd sow it on the break at 25–35 kg/ha, graze it once it passes the pluck test, and apply nitrogen after grazing to keep it growing through the cold months. Adding clover lifts protein and supplies nitrogen for spring.

Quite possibly. Annual ryegrass toxicity (ARGT) is caused by toxins from a bacterium that a nematode carries into ryegrass seed heads, and it's most dangerous from flowering into summer, including in hay. Move stock quietly off suspect paddocks, as stress makes it worse, and call your vet. To prevent it, sow certified Safeguard, the ARGT-resistant annual ryegrass, and stop seed heads forming in infested paddocks.

Two different ryegrass problems cause staggers. Perennial ryegrass staggers comes from endophyte toxins in older perennial varieties, peaks in summer and autumn on short pasture, and most animals recover once moved. Annual ryegrass toxicity (ARGT) comes from toxic seed heads, strikes from flowering into summer and is often fatal. Move stock quietly off the paddock and call your vet.

Sow annual and Italian ryegrass on the autumn break, usually late April to early June, into moist soil. Early sowing grows the most winter feed, and in drier districts it lets early-maturing varieties set seed before spring dries off. Perennial ryegrass can go in with the break too, or in early spring under irrigation. Sow no deeper than 1–2 cm into a firm seedbed.

Graze ryegrass when most tillers have grown two and a half to three new leaves, and take it down to about 4–5 cm. Grazing earlier eats into the plant's energy reserves, while waiting longer wastes feed as old leaves die. Let the leaf stage set your rotation, so it stretches out in cold weather and shortens as growth picks up in spring.

Cut ryegrass silage at the late boot to early head stage, just as the first seed heads emerge. That's the best trade-off between bulk and quality; digestibility falls quickly with every week after heading. Wilt to around 30–35% dry matter for pit silage or 40–50% for baled silage, and seal it quickly. Later-heading varieties, including many Italian ryegrasses, give a longer window to cut.

It can, if the pasture is allowed to set seed before the paddock goes back to crop. Pasture varieties aren't bred for herbicide resistance, but they add seed to the seed bank and can cross with resistant weedy ryegrass. End the pasture phase with seed-set control, such as spray-topping, a hay or silage cut, or heavy spring grazing. In badly affected paddocks, sow a legume-based pasture instead.