Clover - DairyNZ

Types of Clover

Clover is a high-quality feed. There are a number of clover species available with white clover and red clover the most commonly used.

White Clover

White clover is perennial forage legume important in New Zealand dairy pastures. It is grown throughout New Zealand and performs well on moderate to highly fertile soils, but being summer active can be less productive and persistent in dry situations.

White clover has three characteristics that make it an ideal companion species to ryegrass:

It is summer active, with optimal growing temperature 5°C higher than perennial ryegrass
It maintains higher feed quality in late spring, at the time grass plants seed, so helps maintain the milksolids production from pastures
Fixes N in pastures, improving total pasture production and helping develop organic matter in poorer soils.

Grazing management

Good grazing management (grazing at the right time and maintaining consistent grazing residual) allows light into the base of the pastures to prevent shading and promote white clover growth. This is particularly important in mid-late spring, as white clover has little winter growth and is slower to start growing in spring.

A clover stolon has a number of growing points along it as indicated (by white arrows). A high number of stolon growing points improves persistence, as each has roots and is a potentially a new plant.

White clover types

White clover cultivars are classed on leaf size, with large-leaved cultivars generally more productive, but medium-leaved having a higher growing point density making them more persistent.

Large-leaved: cultivars grow taller and more upright, have thick stolons and robust roots. They tend to be higher yielding, but have fewer stolon growing points and less capacity to regenerate and persist. For this reason they typically sown mixed 50:50 with medium-leaved cultivars.

Medium-leaved: cultivars are intermediate in features. The original Grasslands Huia was widely sown, but has now been superseded by a range of modern cultivars with higher yield potential and better robustness through much greater stolon densities. Medium-leaved types perform well under a range of grazing managements, and are typically mixed 50:50 with large-leaved types when sowing dairy pastures.

Small-leaved: cultivars are generally not used for dairying. They are low growing, lower yielding, and their low-growing habit makes it difficult for dairy cows or calves to graze them. They are best suited to sheep grazing.

Dry matter yield

White clover is usually sown as a part of mixed sward pasture, where its DM yield varies from < 1 t up to 7 t DM/ha/year. On new dairy farm conversions where soil N concentration is low and reserves have not yet been created with organic matter, white clover contributes significantly to DM yield, but its contribution in developed farm situations is seldom over 30% at a single grazing and often much less.

In contrast animal performance from pastures improves markedly with increasing clover content, up to 50% or more, so is highly desirable to maximise clover content for high cow performance.

Research has shown clover can survive in pastures with up to 200 kg N/ha/year of fertiliser N when pastures are very well grazed and the clover stolons are not subject to excess shading.

Pests

Insect pests, including clover root weevil, clover flea, slugs, and soil dwelling nematodes severely damage white clover content in pastures in some regions. Since its discovery in 1996 clover root weevil has spread throughout New Zealand causing an almost complete disappearance of clover from pastures typically for 1-2 years.

For more see Managing profitably with clover root weevil (Farmfact 1-25).

What to sow

White clover is generally sown in a pasture mix at 3-4 kg/ha, usually a mix of two cultivars based on leaf size and stolon growing point density.

Red Clover

Red clover is a short lived (typically 2-4 years), tap rooted legume most commonly sown in summer dry areas where summer grazing is less intensive.

In intensive grazing systems red clover typically does not perform or persist well.

It can last up to 7 years under favourable conditions, particularly lax grazing or where a long summer grazing rotation is used.

Under irrigation pure swards of red clover can grow 17 t DM/ha/year, less than lucerne in this situation, but typically red clover DM yields are much lower in a mixed pasture where it must compete with other species.

Red clover shows greater tolerance to clover root weevil than white clover.

Red clover in a mixed pasture.

What to sow

Red clover should be sown in mixtures at 4 kg/ha for diploid cultivars, with tetraploid types sown at heavier rates because of their larger seeds. It needs a sufficient plant density to contribute well in a pasture, because it does not spread like white clover, nor re-seed readily.

White clover requirements

White clover is the base legume of New Zealand dairy pastures sown in a wide range of pastures and management systems. It has a high nutritional value and fixes atmospheric nitrogen (N) to make a substantial contribution to the growth of companion grasses.

A summer active, perennial legume, white clover has an optimal growing temperature 5 degrees higher the ryegrass.

The rate of leaf appearance of clover leaves is mainly influenced by temperature, and leaf size is influenced by light - shade is detrimental to growth.

The clover leaf does not regrow after grazing. A stolon branches from nodes and spread out in the pasture. Light intensity speeds up the production of these daughter stolon's.

White clover is generally more resistant to grazing than ryegrass, the energy reserves are stored in the stolon and root, the stolon stays close to the ground so is rarely grazed.

Clover growth habit means that there will be leaves at varying heights from the ground, some of which will not be grazed.

White clover fixes N in pastures, improving total pasture production.

What does this mean for grazing management and nutrition?

White clover maintains high quality in late spring and summer. Animal performance can improve markedly with increased cover content.

White clover will be preferentially grazed due to its high feed value; however, it has more resistance to hard grazing than ryegrass with some leaves left after a grazing event.

Ongoing pasture management influences clover content in pastures. Leaving ryegrass pastures past the 3-leaf stage will shade clover from light.

This is particularly an issue in late spring when grass growth rates are very high.

Excessive use of N fertilizer (>200kgN/year) will give a competitive advantage to grasses, which may result in shading out clover.

See Good clover -ryegrass mix vital for a productive pasture

Subterranean Clover (Sub clover)

Although subterranean (or sub) clover is the most widely sown annual legume in summer dry areas of New Zealand, it is rarely suited to dairy farm systems. It must be allowed to seed in the first year, and in autumn pastures need hard grazed and kept very short (e.g. <1000 kg DM/ha) to allow space for seedling regeneration.

It establishes in autumn and grows from rosettes to produce long, horizontal stems during late winter and spring.

Sub clover buries it seed. Self-pollinating flowers grow off runners on the soil surface and then the seed containing burrs push into the soil to bury the seed to survive the summer.

Seeds germinate when rainfall resumes, but seedlings can die during subsequent dry spells (false strike)

What does this mean for grazing management and nutrition?

Sub clover is often sown with white clover in a pasture mix in very dry environments, and will survive in conditions too dry for white clover.

Sub clover has its highest yields in late winter and early spring.

Grazing pressure during flowering in the first year of sowing can affect seed set. Summer grasses must be controlled to minimise competition for newly germinating and establishing seedlings in the autumn.

Red Clover requirements

A short-lived, tap rooted plant with dull hairy foliage, usually bearing a distinct leaf mark.

Most common in summer dry areas, where the tap root allows it to tolerate dry periods.

It performs best under moderate stocking rates, long summer grazing rotations or hay production. Under high stocking rates or fast summer grazing rotations its persistence is reduced.

Red Clover has poor winter growth but can provide superior DM production to white clover during dry summers.

What does this mean for grazing management and nutrition?

Red Clover usually persists for 2-4 years in mixed swards. It conserves well as silage and is usually mixed with grasses, other legumes, and grazing herbs. It is often included with white clover in pasture mixes.

Because of it upright growing habit, red clover does not tolerate hard grazing regimes. The species must be established at a sufficient plant density to contribute well in pasture as it does not spread like white clover, nor reseed readily.