French serradella - use and management

Page last updated: Thursday, 24 January 2019 - 12:19pm

Cadiz, Eliza, Margurita and Erica have different characteristics allowing them to be used in different agricultural systems. Cadiz and Eliza are soft-seeded, giving them a limited capacity to self-regenerate, consequently they are useful in 'phase farming' to control herbicide resistant weeds. Margurita and Erica are hard seeded, being useful in rotation with a crop.

Use in farming systems

As Eliza and Cadiz are soft-seeded, their self-regenerating capacity is limited. However, seed can be produced easily on-farm, particularly in good seasons, and stored for regular resowing. Being highly germinable in the pod, it does not require the additional cost of processing to remove the seed from the pod and scarification. It can therefore be used in different ways depending on the farming system, particularly when a low cost seed source is required.

For example, Cadiz is popular in ‘phase farming’ systems as part of a strategy to control herbicide resistant crop weeds on sandy soils. In this scenario, Cadiz is sown and used as grazed pasture for 1-2 years. Weeds are controlled during the pasture phase through a combination of grazing, applications of non-selective herbicides (brown manuring), cutting (for example, for hay or silage production) or cultivation (green manuring). Experience so far suggests Cadiz seed viability can be maintained for a number of years (up to four years) under good storage conditions.

Green french serradella pods
Figure 1. Green french serradella pods

Productive French serradella pastures fix substantial amounts of nitrogen for following crops and improve soil health. Nitrogen content of the plant tops ranges between 2.5-4%. Erica and Margurita are hard-seeded varieties and can survive intensive crop rotations given adequate seed production (for example, one pasture:one crop).

The proportion of hard-seed at the start of summer can be up to 90% then starts to decrease towards the end of the summer, reaching values of 40-60% by midwinter. This particular pattern of hard-seed breakdown avoids high amounts of germination on un-seasonable rainfall events. The persistence of hard-seed across seasons will be sufficient to regenerate as a second year pasture or after one year of crop. In most situations Margurita has a greater rate of hard-seed breakdown than Erica.

Seed production and subsequent seedling density in regenerating pasture at Pingelly, WA
Cultivars Seed produced in establishment year (kg/ha) Regeneration in the second year (plants/m2) Regeneration after one year crop (third year) (plants/m2)
French serradella - Cadiz 381 2059 0
French serradella - Erica 581 728 3733
French serradella - Margurita 374 1328 4289
Yellow serradella - Santorini 1313 111 1333
Subterranean clover - Dalkeith 181 (seed) 506 2778

New pasture establishment

As with other pasture legumes, French serradella should be treated as a seed crop in its first season to ensure maximum seed production. Spraytop the paddock in the previous spring or select a paddock coming out of a cereal or oil seed crop where broadleaf weeds have been successfully controlled. Apply a knockdown herbicide after weed emergence and prior to sowing. In high rainfall regions, delay sowing to achieve good weed control with the knockdown herbicide. In low rainfall regions, decrease weed burden in the previous season then sow French serradella as close to the break of season as possible.

French serradella will usually nodulate in soils with a previous history of lupin crops or pastures. However, it is recommended that seed for sowing be inoculated with Group S inoculant. This can be done by the peat slurry and lime pelleting technique, or by using Group S dry granular inoculants at the recommended rate.

Recommended sowing rates are 10-20kg/ha of pod for Eliza or Cadiz and 3-7kg/ha of naked seed for Erica or Margurita. These rates may be decreased when sowing as a component of a pasture mixture. For optimal establishment, French serradella should be sown shallow (1-2cm depth). This is best achieved by drilling with a tine or disc implement. However, dropping seed on the surface and covering with trailing harrows can also be successful. In most situations establishment is improved with the use of press wheels when drilled, or rollers if top dressed and harrowed. Fertilise new sowings of serradella with at least 150kg/ha of superphosphate, or super-potash on sandy soils.

Pests and diseases

It is important in the establishment year to control redlegged earth mite until plants have at least three true leaves. After this stage French serradella has good tolerance to these pests. French serradella has excellent tolerance to aphids such as blue-green and cowpea aphid and these are not expected to be serious problems or require control. However, native budworm (Helicoverpa caterpillars) and western flower thrip (Frankiniella occidentalis) can severely affect seed production.

Damage by thrip infestation appears as wilted and brown flowers and the pods develop with bent distortion. The damage by budworm appears as holes eaten through the sides of the pod. On finer textured soils, lucerne flea can cause serious damage at the seedling stage. In new sowings the best way to deal with pest problems is frequent monitoring and timely control.

Self-regenerating stands tend to be more resilient. However, monitoring for major pests, particularly budworm in spring, is highly recommended. No serious diseases have been observed on serradella in Australia. Root rot can occur in waterlogged soils and there have been rare cases of hypocotyl rot (Pleiochaeta). It is not susceptible to clover scorch or phoma black spot.

Herbicides

Broadstrike®, Spinnaker® and Raptor® are registered herbicides for broadleaf weed control in French serradella. Grass weeds can usually be controlled with a selective grass herbicide. Agronomic advice should be sought to receive the most up-to-date herbicide information.

Excellent control of problematic weeds, such as wild radish and annual ryegrass, has been achieved through the application of non-selective herbicides applied with a wick or blanket wiper when the weeds emerge above the height of the serradella.

Grazing

Graze the pasture lightly in the establishment year, removing stock in early spring to maximise seed production. Lightly graze over the summer to reduce the stubble. Cadiz and Eliza seed, being soft-seeded, do not survive ingestion by grazing animals, while up to 20% of Erica and Margurita seeds may survive passage through sheep, and considerably more through cattle.

In later years, it is essential to graze the pasture heavily during winter to maintain a serradella dominant pasture. During spring, grazing pressure should be reduced to encourage good seed production. No livestock disorders have been associated with French serradella in Australia.

French serradella seeds and pods
Figure 2. French serradella seeds and pods

Production and marketing

Cadiz, Eliza and Margurita are protected under the Plant Breeders Rights Act 1994. Under the Act there is no restriction on producing seed for personal use (farmer’s privilege) or from sale of produce, such as hay or silage. However, sale of Cadiz or Margurita seed can only be carried out by agreement with the current licensees.

Unauthorised propagation of seed for commercial purposes or sale of these varieties is an infringement under section 53 of the Plant Breeders Rights Act 1994 and is subject to prosecution.

Acknowledgments

Cadiz was developed in a collaborative project between the Department of Primary Industries and Regional Development (DPIRD) and the Cooperative Research Centre for Legumes in Mediterranean Agriculture (CLIMA), with part funding from the Rural Industry Research and Development Corporation. Erica and Margurita were bred by DPIRD and field tested as part of the National Annual Pasture Legume Improvement Program, partly supported by the Grains Research and Development Corporation and Australian Wool Innovation Pty Ltd.

Contact information

+61 (0)8 9368 3907

Authors

Angelo Loi
Clinton Revell