A recent B+LNZ Central Canterbury Farming for Profit field day at Rakaia Gorge’s Quartz Hill Station focused on growing great grass and this starts with selecting the right pasture species for the environment and farm system.
While Quartz Hill Station Manager Gus Lang outlined his approach to maximising pasture production, Growing great grass Allister Moorhead and Greg Dunshea from Agricom talked about different pasture species and their specific management requirements.
What pasture species to choose?
Greg Dunshea, a Forage Systems Agronomist, outlined the physical and management characteristics of different pasture species including perennial ryegrass, annual and Italian ryegrasses, cocksfoot, tall fescue, prairie grass and timothy. He also covered weed species such as couch/twitch, browntop, annual poa, ripgut brome, barley grass, Yorkshire fog, sweet vernal and crested dogstail.
Perennial ryegrass
Perennial ryegrass is by far the most commonly used pasture species in this country’s livestock systems. It is easy to establish, producing high ME feed for most of the year, but can decline in quality over summer due to dry and hot conditions, hence the need for complementary pasture species i.e. white and red clover, chicory, plantain and cocksfoot.
“Ryegrass is easy, but it is prone to moisture stress and insect damage (although novel endophytes address this issue) and is not suited to lax grazing,” says Dunshea.
It is designed for intensive pasture management.
Tall Fescue
While slower to establish than ryegrass, it is a good companion species for herbs and legumes and is often higher yielding than ryegrass. It tolerates poorly drained soils but does require good soil fertility. Often tall fescue paddocks are taken out due to the ingress of grass weeds such as browntop that are competitive with fescue in low fertility situations.
“Aim to maintain an Olsen P of over 20 and consider the increased productivity of fescue paddocks when applying maintenance fertiliser.”
Tall fescue plants have thick root systems which make them tolerant of both drought and insect pests. Ideally, Tall Fescue likes a high water table, but also tolerates hot, dry conditions.
To get the most out of tall fescue, effective management is key - it should be sown in blocks, not just in one paddock.
“Placing tall fescue in areas with good laneways and infrastructure to allow for easy stock movement is beneficial and using paddocks that have the option of harvesting for silage or baleage will greatly assist with managing tall fescues rapid spring growth, “says Dunshea.
“Aim to have a functional amount in a farm system, e,g 30 percent of your pasture.”
Tall fescue changes rapidly between September and October, switching from slow winter growth to rapid early spring growth driven by the plants reproductive cycle. During this period the feed produced needs to be well managed by fast and intensive grazing rounds, shutting up paddocks for baleage or silage. If quality declines from elevated grazing residuals and/or the presence of seedhead, cutting silage/baleage or topping are great ways to reset the sward.
Tall fescue suits an early lambing date, spring cattle grazing once winter feed crops are finished, and as a high-quality forage for velveting stags as the early spring period is when it is at its most productive.
It does require specific management in the autumn – lifting grazing residuals to 1600-1700kgDM/ha and extending grazing rounds to 30- plus days from March to May is highly beneficial to both persistence and spring growth.
Cocksfoot
Cocksfoot is ideal in low fertility, free draining soils. It is also tolerant of insect pests.
An aggressive competitor for soil moisture, it produces good feed for cattle and is beneficial in sheep systems where drought can restrict ryegrass growth. In general sheep will eat it, but a lower feed quality makes it not well suited to finishing lambs.
Cocksfoot can clump under lax grazing but is ideal in areas where pasture persistence is a problem. Occasional hard grazings or, where possible, making supplement from paddocks can be beneficial in reducing ‘clumping’
“If pastures reverting to browntop is an issue, then include cocksfoot in your pasture mix, it has so much more going for it than browntop.”
The inclusion of low rates (2-6kg/ha) of cocksfoot in ryegrass pasture mixes can be highly beneficial in creating pastures with increase drought resilience and persistence.
Cocksfoot responds very well to autumn applications of nitrogen, which increases pasture yield and quality heading into winter.
Prairie Grass
Prairie grass is a prolific seeder with palatable seed heads. It is winter active and relatively drought tolerant. It can tolerate water logging, pugging and acidic soils.
Timothy
While slow to establish, Timothy is well suited to intensive grazing. It is highly palatable, late flowering and complements legumes in the pasture.
White clover
Not all white clovers are created equal and different varieties will suit different environments and grazing systems. Some can be vulnerable to damage from over-grazing resulting in reduced persistence, so it is important to select the correct variety to suit the system.
“It is horses for courses.” Large leaf size cultivars (Brace), suit cut and carry systems and cattle based grazing systems. Medium leaf size cultivars (Attribute) are able to tolerate intermittent hard grazing and be highly productive under general rotational grazing. Small leaf cultivars (Emblem) are able to persist very well under set stocking and repeated hard grazing systems
Alternative grasses
Allister Moorhead said national sales of alternative (non-ryegrass) pasture species have trended downward in recent years. While typically slower to establish than ryegrass, they do offer other advantages including drought tolerance, persistence and generally improving farm resilience. It is likely farmers who have gone away from using these species in recent years will notice their absence if the predicted super El Niño arrives.
“It is not so much about worrying about what has occurred in recent years climate wise, it is more about safeguarding for the future and recognising the value of being consistent with their use in your programme to maintain resilience.”