Family: FABACEAE/PAPILIONACEAE
Tagasaste or tree lucerne as it is also known, is a nitrogen fixing legume native to the Canary Islands and is one of our most useful pioneer species. It is generally fairly short lived, although regular cutting or browsing can considerably extend its life expectancy. Today, it is a naturalised coloniser of Australian wastelands capable of surviving on a wide range of soils. In Western Australia 50,000 ha of mostly marginal farmland has been planted to tagasaste (by 1996). It is estimated that 1.5 million ha of Australian farms could benefit from tagasaste.
It grows to a height of up to 7 m and is capable of productive growth in areas of low rainfall (300 mm). Drought tolerance is improved if phosphorous is readily available. Liberal applica-tion of rock phosphate at planting time works well. The nitrogen fixing bacteria does not generally need introduction with the plant as it is usually present in the soil from other species including Acacia spp, Albizia spp, Cassia spp, etc.
Tagasaste is a fast growing, highly productive stock feed with high nutrition levels, low toxicity and a high degree of palatability.
Comparison of Tagasaste Foliage with Other C o m m o n Stock Feeds
Composition expressed as a percentage of the dry matter
(Based on Snook 1986)
Constituents | tagasaste | lucerne | rye | wheat | f i e l d p e a |
grass | grain | seed | |||
Crude Protein | 17-31 | 21 | 16 | 11 | 26 |
Carbohydrate | 38-58 | 40 | 46 | 82 | 63 |
Crude Fat | 2 - 6 | 3 | 4 | 2 | 1 |
Crude Fibre | 14-30 | 26 | 24 | 3 | 7 |
Total Ash | 4 - 10 | 10 | 10 | 2 | 3 |
Calcium as Ca | 0.48- 1.62 | 2.2 | 1.0 | 0.04 | 0.24 |
Phos. as P | 0.12-0.41 | 0.33 | 0.26 | 0.24 | 0.24 |
In early work at the Martindale Research Project at New Norcia in Western Australia, on near useless sandy soils, capable of yielding only 700 kg of wheat, tagasaste has yielded the feed equivalent of 1100 kg of wheat. The researchers also found that the ovulation rate and the twinning rate of ewes on the tagasaste was significantly higher than their flock mates on dry pasture or a lupin stubble. 45 ha of tagasaste in rotation, easily fed 650 ewes (in lamb) for 56 days over summer, increasing the average live weight from 51 to 52 kgs. This area recovered before further rainfall.
Martindale's trials have established that ewes on tagasaste over summer/autumn grew 30% more wool, with the same yield, but slightly broader micron, compared with their traditionally managed flock mates.
Dandaragan farmer John Cook has claimed that tagasaste can lift profit from $6/ha to $30/ha in his area.
To maximise the stock feed potential of tagasaste, the trees should be trimmed at a very early age so that they tend to bush rather than become erect trees. This keeps the habit low so that stock can reach the foliage and ring barking is virtually impossible. Ideally these trees are arranged into lock - up fodder systems to allow the trees time to recover from grazing and to avoid the time consuming cut and carry method. Well fenced hedge rows can be constantly grazed.
Stock Carrying Capacity of Tagasate Compared to Pasture
(Based on Snook, for Margaret River, W.A. Planting density - 1000/ha)
YEAR | 1 | 2 | 3 | 4 | 5 | 6 |
Tagasaste
Edible yield/ha/yr
(tonnes dry matter) | - | 2.7 | 5.4 | 9.4 | 16 | 19 |
Pasture
Edible yield/ha/yr
(tonnes dry matter) | 5.5 | 5.5 | 4.0 | 2.0 | 1.0 | 1.0 |
Stocking Rate
Sheep/ha
Tagasaste Only | - | 5 | 10 | 17 | 29 | 35 |
Tagasaste & Pasture | 10 | 15 | 17 | 21 | 31 | 37 |
Tagasaste is also a valuable source of feed for bees and it flowers in the winter, a time when little else flowers. Cutting different plants at different times can significantly extend the flower-ing period of a stand of tagasaste. It is a prolific producer of seed which is valuable as a free -range chicken forage. Poultry gain benefit from tagasaste leaves as a source of greens. Tagasaste is readily eaten by other types of stock, such as pigs, horses and rabbits, and can comprise a major portion of their diet. Rabbits in the Canary Islands, reared on tagasaste, are said to produce exceptionally tasty meat.
Comparison of Tagasaste Seed with Other Poulry Feeds.
Composition expressed as a percentage of the dry matter (Based on Snook 1986)
Constituents | tagasaste | oat | wheat | field pea |
seed | grain | grain | seed | |
Crude Protein | 25 | 10 | 11 | 26 |
Carbohydrate | 54 | 69 | 82 | 63 |
Crude Fat | 12 | 4 | 2 | 1 |
Crude Fibre | 6 | 13 | 3 | 7 |
Total Ash | 3 | 4 | 2 | 3 |
Calcium as Ca | 0.07 | 0.06 | 0.04 | 0.24 |
Phos. as P | 0.40 | 0.14 | 0.24 | 0.24 |
Tagasaste can be used as a nurse crop for other trees. In trials conducted in New Zealand with various fruit and nut trees, it was found that trees growing in close association with tagasaste (as close as 1 m) consistently grew better than the controls without tagasaste.
When tagasaste is grown this close to other trees it may influence the tree's shape. If a tree is grown for timber, then the tagasaste will tend to force the tree up for light, and provided it is surrounded with tagasaste, it should produce a good straight, long timber tree. If the nursed tree is required to produce fruit or nuts then a spreading habit is usually desired, to allow easy access to fruit. In this case the tagasaste should be clipped and used as a mulch around the nursed tree or fed out to stock if necessary.
The wood is a good firewood and has potential as a hard, light wood for tool handles and craft work.