Pasture Persistence

No single solution to persistence but some management practices will help.

Messages from the New Zealand Grasslands Association Pasture Persistence Symposium. Hamilton, 10 & 11 May 2011.

Summarised by the Pasture Renewal Leadership Group.

Lack of persistence has many overlapping causes, and there is no stand out solution.

Causes of poor pasture persistence include:

Insect damage, e.g. clover root weevil, black beetle
Drought
Use of an inappropriate endophyte (e.g. AR1in upper North Island)
Drilling annual ryegrasses into perennial pastures
Increased feed demand on pastures
Reduced natural re-seeding, resulting from plant breeding and management for pasture quality
Poor soil structure and low fertility are occasionally problems.

The Solutions: A range of solutions were proposed but there are no silver bullets.

Grazing management

Grazing management can make a difference

Pastures replace themselves naturally through tillering of grasses and stolon growth of clovers. Some grazing management practices assist this process and some slow it down
November is a critical period. Seed-heads appearing in October/November die when grazed or cut. New tillers must replace them. A high tiller replacement rate before summer improves persistence
Grazing management practices that enhance replacement rate are:

November/December nitrogen applications of 20-25kgN/ha
Avoid grazing pastures below 4cm residual other than in winter.

Grazing management practices that reduce tiller replacement rate are:

High pre-grazing covers (more than 3,000kg DM/ha), or allowing hay/silage paddocks to get too long before harvesting. New tillers don’t get enough light and die
Hard and frequent grazing events during drought conditions.

Further reading: DairyNZ Farmfact 1-20 How do pastures grow?

Insect management

Manage insect pests to minimise their impact – they cannot be eliminated.

Select appropriate endophytes
Use treated seed at sowing
Use crops to break insect cycles
Some crop sequences reduce insect populations (eg turnips, maize, chicory), while others attract insects, (e.g. annual ryegrasses).

Further reading: Pasture Renewal Best Practice Guide

Pasture species other than ryegrass and white clover

Where ryegrass persistence is a problem due to summer dry and/or insect challenges options such as tall fescue and lucerne can be considered
Alternatives to ryegrass have different seasonal production patterns that need to be understood if milksolids production is to be matched or improved.

Discuss options with your seed company representative or farm consultant.