Legumes are an important component of NZ perennial pastures whether they are finishing properties or less developed hill country properties with tussock and oversown pastures. The predominant legume is white clover and it is incorporated in to all or most perennial pasture mixtures, both for the feed quality component and the ability to fix nitrogen.
White clover has three characteristics that make it an ideal companion species in a pasture, and in particular with perennial ryegrass. First, it is summer active, with an optimal growing temperature 5°C higher than perennial ryegrass. Second, it maintains high feed quality in late spring and summer, at the time grass plants set seed, thus helping maintain the nutritive value of grass/clover pastures. Third, white clover fixes nitrogen in pastures, improving total pasture production and helping develop organic matter in poorer soils.
White clover cultivars range from small-leaved, low growing and lower yielding to large-leaved upright types. The larger leaved white clover varieties will be better suited to grazing by deer but may be less persistent if they are strongly selected for by the deer.
White clover levels in the sward vary but are usually less than 10-20% of the forage available. However animal performance is usually higher on swards with higher levels of clover.
Red clover is a shorter lived legume (2-4 years) compared to white clover depending on grazing management. It is a tall tap-rooted plant with large hairy leaves. It is summer active and flowers later than white clover, but has poorer winter growth. There is an opportunity to use red clover in summer dry areas especially with lax grazing or long rotations or as a silage crop. Pure stands of red clover can produce up to 17 t DM/ha/yr under favourable conditions (good fertility and moisture or irrigation).
Red clover is one of the cultivars shown to be highly preferred by deer. While white clover is stoloniferous which means it spreads and produces daughter plants, red clover produces shoots from a crown which can be damaged by grazing and treading therefore reducing the plants persistence. In addition red clover is dormant over winter so grazing needs to be avoided.
The best grazing management for deer is rotational grazing with a 3-5 week break depending on the time of year. Allowing the deer to graze for too long or too close to the ground will reduce red clover persistence. Research has shown weaners, hinds and calves and adult deer all grew better on red clover when compared to ryegrass white clover pastures.
Lucerne is a high quality, deep-rooted perennial legume. Its yield potential will depend on the depth fertility and available water holding capacity of the soil where it is sown. For optimum performance and ease of management lucerne is best sown as a stand-alone crop. Lucerne is different from a grass pasture in how it grows and recovers from grazing, its seasonal production and quality and most importantly its overall grazing management and integration into a farm system.
Lucerne is highly preferred by deer, similar to red clover and chicory. Farmer experience has shown deer do very well on lucerne, including weaners and lactating hinds and their calves. A critical factor in lucerne management is the time taken to adjust to the change in diet. Deer need about 10 days for the rumen to adjust to the lucerne, but they can be fed a mixture of grass and lucerne during the adjustment period. The addition of roughage (straw) and provision of salt licks help with any health issues.
The grazing management requirements need to be well understood before introducing lucerne into the farm system. These include planting enough lucerne to keep stock on lucerne for at least 6-8 weeks once they have adjusted to the diet, and to allow for a 5-6 paddock/break grazing rotation. This will allow best management of both the deer and the lucerne stand.
Lucerne is a perennial legume with a long taproot that can access water and nutrients from deep in the soil profile. Lucerne has excellent growth and quality, and is very persistent if managed well.Lucerne can grow up to 20 tonne DM/ha on irrigated areas, and 10-15 tonne DM/ha from deep dry-land soils. The life of the crop is directly related to the management, but stands over 15 years old have been seen in drier areas where the pressure from weed grasses is less, with a more typical range of 5-8 years.
- Low average rainfall (suitably under 1000mm per annum)
- Free draining soils
- High fertility soils with a pH in the range of 6.0-6.4
- Use or would like to use rotational grazing systems
Planning
Speak to your local consultant about the steps to follow when planning your lucerne crop.
- Planning assistance could include help with identifying the most suitable paddock/s for the lucerne to be sown
- Undertake soil pH tests
- Review any weeds, prior crops in chosen paddock as this can affect result of the lucerne crop
- Assistance with ensuring that suitable fertilisers are used in tandem with chosen lucerne seed
NOTE: Avoid sowing Lucerne in paddocks that have just come out of lucerne.
Establishment phase
- 'Weeds weeds weeds' -an important part of a successful crop is managing weeds and pests which can greatly affect the outcome of your crop.
- Spring sown legume (suitable sowing date is Mid-August - September, however Autumn sowing can also be successful)
- Once the free draining paddock has been chosen and a fertility test has been completed you can assess the requirements i.e. fertiliser when sowing
- The seed needs to be sown at least 10 to 15mm deep into a stable moisture zone. At this depth the seed will not be affected by frosts and are more capable of being able to survive a dry spell. Deeper than this the seed will not survive.
- A sowing rate of 15-20kg/ha seems to result in a better canopy cover on the lucerne which assist with retention of moisture and a better result.
- Inoculation of the seed is a vital step in the process of having a successful establishment. As without inoculation the lucerne will not fix nitrogen properly.
- Full cultivation will give a better result as this process assists with the management of weeds and also with the correction of any fertility issues, however direct drilling is also used and is the cheaper option.
Ongoing management
- Allow the lucerne to reach a minimum of 50% flowering (50% of the tallest stems have a flower) prior to the first grazing or cutting.
- Weed management is important during early establishment, with pre and post emergent chemicals available. Talk to your local consultant for advice on what product to use. Insect pests such as lucerne flea, red legged earth mite, grubs, weevils and aphids love to attack lucerne.
- To graze with lucerne it is best to have 5-6 paddocks of it in the rotation. This allows enough time for the first paddock in the rotation to recover before the next round.Start to graze the first pasddock when the lucerne ios 20-25cm high.The following paddocks will be taller when walking into the paddocks.
- Graze for approximately 5-7 days or until all green leaf and some stem is gone.
- Allow approximately 40 days between rtoation onto the first paddock to allow for leaf and stem recovery.
- Adjust stocking rate or length of rotation based on height of lucerne when walking into it, premium level is 20-30cm in height. (Approximate stocking rate figures is 10-12su/ha at suitable crop height, seek advice on this if unsure on your crops DM level.)
Lucerne root 8 months after sowing (1.5m in length)
Although lotus is highly preferred by deer the plant is difficult to establish and persist successfully in a pasture. Lotus varieties are often promoted for use due to the nutritional benefits of condensed tannins (CT). Research has shown improved liveweight gains and possible reduced gastro-intestinal parasite burdens may be linked to CT levels in the herbage. However their ineffectiveness as a pasture plant and the difficulty in sourcing seed limits their use.
