Overview
Tagasaste (Chamaecytisus palmensis)
Features
Tagasaste for autumn feed
Tagasaste for Year-round grazing
How to maximise year round grazing on Tagasaste
Seasonal growth patterns of Tagasaste
Changes in Feed quality of Tagasaste
Establishment
Site selection: Soils and climate
Rhizobium and nitrogen fixation
Seeding method
Fertiliser application in the first year
Pest and insect control
Grazing management during establishment
Mature stand management

Overview
Fodder Shrubs along with Sub Tropical Grasses are important for providing year round grazing in Mediterranean environments. Fodder shrubs comprise two main types, Tagasaste and Saltbush. Tagasaste is the main fodder shrub used in Western Australia and possess the following attributes:

It increases total feed production and animal carrying capacity on deep sandplain soils. It shows best growth on good quality sandplain soil but also thrives on deep pale sands where cropping is generally uneconomic.

• Tagasaste supplies green feed throughout the year but most importantly during the Autumn and early winter period when feed is scarce.
  
• Tagasaste enables deferred grazing of annual pastures after the break of season therby increasing total feed production throughout the year.
  
• Tagasaste uses more water than annual pastures and therefore reduce recharge to the groundwater
  
• Tagasaste helps to control wind erosion.

Tagasaste (Chamaecytisus palmensis)
Tagasaste was initially developed to supply feed to sheep during the autumn-early winter feed gap. In this situation, tagasaste was profitable as it replaced the need to supply stock with supplementary feed. There are several sandplain farms in the West Midlands with extensive areas of pale deep sands where about 50% of the farm is planted to tagasaste. On these farms tagasaste supplies the majority of the feed and is grazed year-round by cattle. There are currently about 100,000 ha of tagasaste in WA, mainly in the northern agricultural region. Tagasaste plantations have persisted and been productive under grazing for at least 20 years on deep sands in the West Midlands. Intensive grazing management that is designed to prevent flowering does not appear to weaken the plants or limit their life span.

Features:

• drought-tolerant fodder shrub in areas receiving >350mm
  
• Very productive (compared to annual pastures) on pale deep sands where the growth of annual crops and pastures is poor. It will do better however on better quality deep sands.
  
• can replace supplementary feeding in autumn, but animals will only maintain weight
  
• feed quality and animal growth rates in winter and spring are similar to annual pastures
  
• can be grazed continuously by cattle
  
• sheep should not graze tagasaste for more than six weeks at a time
• requires hard grazing or cutting in the first half of the year to prevent flowering.

Tagasaste for autumn feed:
A whole farm systems experiment carried out at ‘Dunmar’, Badgingarra by the Martindale Research Project found that planting 10% of the farm to tagasaste could replace the need to hand feed sheep in autumn. The tagasaste was locked up for 11 months and then grazed by 100 sheep/ha for about four weeks, which was equivalent to an average stocking rate of 8 DSE/ha over the year compared with 1-2 DSE/ha on volunteer annual pastures. The tagasaste had to be mechanically cut each year as the 11 months regrowth was beyond the reach of the sheep. This system was profitable, despite the cost of mechanical cutting as it replaced grain feeding.

Tagasaste for Year-round grazing
Some sandplain farms have large plantations of tagasaste. In such cases the tagasaste forms the bulk of the feed supply and is grazed throughout the year.
Tagasaste varies seasonally in growth rate and feed quality (see below), but these fluctuations are much smaller than with annual pastures.

How to maximise year round grazing on Tagasaste:
The combination of feed supply and quality means that 80% of the animal liveweight gain from a tagasaste plantation comes from just six months of the year. Farmers should maximise stock numbers/grazing pressure from just after the break of the season through to late spring. Stock numbers should then be reduced through summer by selling finished livestock and using other feeds such as crop stubbles.

Seasonal growth patterns of Tagasaste

• Tagasaste grows rapidly after the break of the season in autumn, especially in April and May while the weather is still warm.
  
• Growth slows down during the low temperatures in June and July, but the plants do not become dormant.
  
• The highest growth rates occur in spring when there is adequate soil moisture and warm weather.
  
• The growth rate slows down over summer as soil moisture becomes more limiting.
  
• Tagasaste is also affected by high temperatures. When the temperature exceeds 35°C the leaves close up and show signs of wilting, however these symptoms disappear as the plants recover in the evening.

Changes in Feed quality of Tagasaste:

• The feed quality is highest in winter and spring and then declines steadily over summer and autumn (Figure 8.2).
  
• By late autumn tagasaste on its own is only adequate for maintaining animals. During the growing season from May to October animal growth rates on tagasaste should be similar to those on green annual pasture, e.g. cattle growth rates of 1.0-1.8 kg/head/day. Leaves have a dry matter digestibility (DMD) of 70-82%, while fine stems have a DMD of 50-60% and large stems 40-50%.

Establishment
Tagasaste can be established either by direct seeding or by planting seedlings.7, 438
Direct seeding:

• Cheaper than seedlings
  
• Requires more attention in terms of weed, insect and vermin control.
  
• In WA, most stands are direct seeded in winter.
  
• In the mature stand there needs to be a plant every 2 m within a row to create a hedge row.
  
• With direct seeding, there should be about 10 plants/m of row 6-8 weeks after seeding.
  
• Seedling numbers decline over the first year with many stands ending up with about 1 plant/m of row. This density is adequate and productivity is not reduced until the density falls below one plant to every 2-3 m of row.

Tagasaste Seedlings:

• Can be tougher once they are established.
  
• Are susceptible to planting shock.
  
• Potted seedlings cost 50 cents to $1 each with 1,000 to 1,500 plants required per hectare depending on the row spacing.
  
• Bare-rooted seedlings are cheaper than potted seedlings, but are still more expensive than direct seeding.

Site selection: Soils and climate:

• Tagasaste is adapted to deep, well drained soils. It is particularly suited to the highly leached, pale deep sands where annual crop and pasture growth is poor. The deeper the sand the greater the soil volume for the tagasaste roots to explore and the better the plant growth. Tagasaste roots have been measured to a depth of 10 m on a pale deep sand at New Norcia. These sandy soils have a limited water and nutrient holding capacity but this is compensated for by the deep soil profile. A sand with a water-holding-capacity of 40-50 mm/m of soil can store 400-500 mm within the root zone of tagasaste. Physical or chemical properties that limit the rooting depth of tagasaste will reduce production, persistence and water use.
  
• Tagasaste does not tolerate waterlogging or salinity and requires at least 1 m of well drained soil to persist and be productive. When there is a fresh watertable below 1 m then tagasaste is capable of high growth rates and will transpire up to twice the average annual rainfall.209
  
• Tagasaste will not tolerate extreme soil acidity and high aluminium as is common on the Wodjil sands in the eastern wheat belt. The soil pHCa should be 4.0-7.5.
  
• Tagasaste can be grown successfully on a wide range of soils including loamy soils and fine-textured soils, However, fine-textured soils can restrict root growth and are vulnerable to winter waterlogging.
  
• Frost affects tagasaste by burning the tips of the most actively growing shoots. Established plants will not usually be killed by frosts, except where fresh regrowth is burnt off. Seedlings are sometimes vulnerable to frost damage.

Rhizobium and nitrogen fixation:

• Tagasaste is promiscuous, so does not have highly specific rhizobial requirements. It will form effective nodules with a wide range of Rhizobia, including the native or background strains that are present in the soil. Seed can be inoculated with a commercial strain of Rhizobium, i.e. ‘Tagasaste special’ CC1502, but it is not essential.
  
• Tagasaste can fix atmospheric nitrogen, however like all legumes it is cheaper for the plant to extract nitrogen from the soil when it is available. In an older stand much of the plant nitrogen can be recycled from the soil profile rather than being fixed by the rhizobia. In a young stand high rates of N fixation (83-390 kg N/ha) have been reported.

Seeding method:

• Tagasaste is planted and seeded with specialist machines that scalp away the topsoil to form a furrow.
  
• The scalping helps to remove weeds from near the seedlings and also to collect water. Generally no further weed control is required, but the seedlings need to be monitored closely for insect damage.
  
• Deep ripping below the seed along with scalping help to ensure that tagasaste seedlings survive their first summer.

Fertiliser application in the first year

• Applying fertiliser at seeding may have limited benefits on plant establishment, however fertiliser applied in the first spring once the seedlings are established can be beneficial.
  
• For small seedlings the fertiliser is only applied along the scalped furrow rather than being spread over the whole paddock.
  
• Superphosphate and potash fertiliser can improve seedling growth greatly but this may not necessarily result in more plants surviving summer.
  
• Applying potash fertiliser can improve seedling growth, but high rates can kill seedlings. Muriate of potash should be applied at 25 kg/km of row (or 25 g/m of row) while rates above 50 kg/km of row can kill tagasaste seedlings.

Pest and insect control

• Young tagasaste seedlings are susceptible to attack by insects, grazing animals or rabbits in their first year. Newly emerged seedlings are at risk from redlegged earthmite, lucerne flea and a range of caterpillars. Spraying the entire paddock at seeding with an insecticide is cheap insurance. Regular inspection of the paddock is also required as new pests can invade the paddock.
  
• In coastal areas wingless grasshoppers hatch in spring. If the hatching sites are identified early then the grasshoppers can be controlled before they become mobile and spread over large areas. New tagasaste paddocks should be inspected regularly for grasshoppers from October until the end of December.
  
• Rutherglen bugs are one of the most serious pests of tagasaste and other shrub/tree seedlings. The adult form of this insect is commonly seen during harvest and is referred to as ‘radish flies’. These small grey insects are attracted to radish plants and fly off in large numbers when approached. However it is the juvenile form of the Rutherglen bug that kills seedlings. These are very small brown to black bugs that are difficult to see, as they tend to hide underneath leaves and only move when disturbed. The juveniles are sap-suckers and can kill seedlings quickly in warm conditions. Their numbers tend to peak during harvest when farmers are often too busy to inspect tagasaste carefully. Whole paddocks of tagasaste can be destroyed.

Grazing management during establishment

• Grazing by livestock or rabbits needs to be controlled during the establishment year. Seedlings should be cut or lightly grazed when they are about 10-11 months old or 25 cm high to encourage the development of multi-stemmed shrubs tolerant to grazing.

Mature stand management

• Once established, tagasaste usually only requires fertilising, good grazing management and the occasional cutting for persistence and production.
  
• Mature shrubs are comparatively free of pests and diseases. They are the last plants to be attacked by grasshoppers or locusts and they readily recover even when all the foliage is eaten.

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