What influences pasture variety decisions?

Have you heard about a new pasture seed but are not sure whether to sow it?

Before deciding whether a new pasture variety is suitable for you it is important to first determine whether the species is a correct fit for your system.

The choice of species will depend on climate, annual rainfall, rainfall patterns, soil types and characteristics such as depth, water holding capacity, pH and fertility levels. The livestock enterprises will also have a major influence on the species selection. The perennial grass species phalaris, cocksfoot, fescues and ryegrasses all have specific climate and soil type requirements to achieve optimum performance. For example perennial ryegrass will not persist in low rainfall regions with hot dry summers. On the other hand, annual ryegrasses can be grown in hot climates because they are generally finished growing before summer heat arrives.

At the variety level some of the key considerations are dry matter production, seasonal growth patterns, persistence under grazing, palatability, spelling requirements, disease and pest tolerances, ability to withstand waterlogging, acid soil tolerance, animal safety and compatibility with suitable companion species. Agronomists and producers also like to see trial data and demonstration comparisons for their regions comparing the new varieties against the local varieties that have stood the test of time.

Hummer tall fescue, Savvy cocksfoot and Mach 1® tetraploid annual ryegrass are examples of some varieties that are currently available that have a fit for particular farming systems.

Savvy cocksfoot is another modern variety which has replaced Porto. Savvy is very soft leaved, making it highly palatable and digestible with high metabolisable energy compared to Porto. Trials in New Zealand have shown that Savvy is only 0.5 Mega Joule (MJ) ME behind perennial ryegrass and there is the same animal live weight gain per hectare as perennial ryegrass because Savvy produces greater dry matter tonnages. Savvy is suited to environments such as soft Tablelands climates, with reasonable summer rainfall and poorer soils, as it can survive on soils with far less water holding capacity then ryegrass.

Mach 1 tetraploid annual ryegrass in a newer mid-heading variety which means it will grow until early November. Being an annual and without the need to persist over summer Mach 1 can be grown on a variety of soil types and areas witch receive minimal summer rain. It is ideally suited to irrigation environments. Early March is considered an ideal planting time if conditions are suitable in cool climates and large amounts of dry matter can be produced prior to winter. However if hot dry conditions occur establishment can be poor. Ideally a full profile of moisture is required for early plantings and preferably with rain on the way. If these conditions are not met then planting should be delayed which will improve the chances of a good establishment but drastically reduces the amount of dry matter which will be taken into the winter period. The ability of Mach 1 to germinate and grow at soil temperatures below 10 degrees gives producers sowing time flexibility. With excellent winter production and outstanding spring production Mach 1 is an ideal grazing/silage or hay option. Trial averages over a five year period show Mach 1 yielding 15,293 tonnes of dry matter compared to Tetila at 12,956 tonnes, which is an 18 percent increase with the newer variety.

In conclusion once the species has been chosen which is influenced by environment, soil type, temperature, rainfall and rainfall patterns the producer must then decide on which variety/ies are likely to best suit their particular systems and livestock enterprise. With the availability of many new varieties a system may include multiple species and variety combinations rather than what has in many regions traditionally been a one species suits all approach. Hummer continental tall fescue is ideally suited to higher altitude higher rainfall areas, or where there is suitable irrigation, to produce quality spring, summer and autumn feed. Large quantities of high quality feed winter/spring feed can be grown with Mach 1 on poorer soil types with the option of silage or hay production and finally Savvy cocksfoot can produce feed which produces similar live weight gain to ryegrass on poorer soil types where perennial ryegrass cannot persist.

References:
Short term ryegrass yield and economics: https://www.ausweststephenseeds.com.au/Research/Systems-Work/ST-Ryegrass-yield

Hummer tall fescue is a soft-leaved continental variety which has replaced Demeter, a tough leaved variety, which persists in lower summer rainfall and poorer soils. Hummer tall fescue is summer active and produces dry matter in spring, summer and autumn but is less productive than Mediterranean fescue, ryegrass and winter active phalaris varieties in winter.

Hummer tall fescue grows in a wide range of locations, from the cooler summer dominant rainfall areas of the Northern Tablelands NSW and through the Central and Southern Tablelands NSW. Hummer can also be successfully grown in warmer irrigation areas such as the Riverina if adequate water is available. In cool climates Hummer tall fescue can be planted in the spring but in warm climates needs to be planted in the autumn. Hummer tall fescue has metabolisable energy (ME) and digestibility far exceeding Demeter and is equal to ryegrass as long as good grazing management is in place. It is less forgiving than ryegrass with grazing management and quickly loses quality if not grazed on time, therefore farmers need to be able to access additional stock or slash the fescue in good seasons. Small paddocks aid in grazing management and only part of the farm should ever be sown to tall fescue.

Providing correct grazing management is carried out Hummer tall fescue is very palatable for animals and can be grown successfully as a standalone species when planted at rates of 20-25kg hectare. It can also be planted with a range of clovers which will provide nitrogen. Red or white clovers are an ideal option. Hummer tall fescue can also be successfully grown with chicory and plantain. Hummer is performing extremely well in many dairy, beef and lamb systems.

There are also some differences in the way tall fescue plants regenerate, compared to ryegrass. The rate of new tiller formation in tall fescue is about one third the rate of ryegrass, but the tillers are three times larger. Tall fescue has two and a half live leaves whereas ryegrass has three live leaves.

Tall fescue requires greater maintenance fertiliser than ryegrass and greater amounts of nitrogen to reach its potential in high dry matter production. Because of its summer activity, deeper root system and more efficient water use, good heavy soil types are required which store plant available moisture. It can be planted on lighter soils as long as it is irrigated regularly. Fescues are tolerant of waterlogged soils.

Hummer tall fescue provides a large quantity of dry matter in the summer, but stock need to be removed to increase drought tolerance if the season turns dry, therefore alternative paddocks need to be available. Hummer tall fescue tillers in the autumn, setting itself up for spring growth, therefore it should not be grazed heavily at this time.

Tall fescues can be difficult to establish so farmers need to ensure a moist, weed free seedbed ensuring good seed/soil contact and seed should be sown no deeper than 15mm. The 9am soil temperature at this depth should be 12 degrees. There are also limited chemical options in the first year so weed control of both grasses and broadleaf weeds needs to take place for at least two years before tall fescue is planted. Hummer tall fescue also has the benefit of Max P® endophyte, which controls the key insect pests; Argentine stem weevil, black beetle and pasture mealy bug, while at the same time not causing any known animal health issues in either sheep or cattle. Hummer tall fescue makes excellent quality grass hay.

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