Asparagus (Asparagus officinalis)
The Asparagus is one of the most delicate, wholesome and lucious perennial plant of the garden. Its erect branching stems, 15-180 cms in length, which are known as spears are used in soups and other products. Asparagus beds once established will continue to produce for many years. It is a good diuretic and is also used in Cordiac dropsy and gout.
The edible portion contains – Moisture 93gm, Protein 2.2gm, Fat 0.2gm, Carbohydrate 3.2gm, Fibre 0.7gm, Ash 0.7gm, Ca 0.025mg, P 0.039%, Fe 0.93mgm, Cu 0.14mgm, Vit A 1400 I.U., B1 180 mgm, B2 130 mgm, C 40 mgm per 100 gm of fresh leaves.
HISTORY AND ORIGIN
It is indigenous to Europe and Siberia from where it has been introduced to other parts of the world.
It belongs to Liliaceae family. The varieties are divided into two groups one with purple spears and the other free from purple colour.
The cultivated varieties are
- Argentevil Early – a selection form the Dutch purple type.
- Argentevil Late – Dutch type.
- Connivers Colossal – an American light green type.
- Marther Washington – an American variety with roundish tipped bud.
- Palmetto – Argentevil type pea green in colour.
- Sutton’s Giant Fresh – Argentevil type with stout buds. The recommended variety of I.A.R.I is Perfection.
SOIL, CLIMATE AND RAINFALL
The best soil suited for its cultivation is light and medium loams or sandy loam soils, well supplied with organic matter. However, under proper treatment it will thrive in any well cultivated soil. It can even be grown in heavy clay soil with deep cultivation and well drainage. The optimum pH required for growing asparagus is between pH 6.0 and 6.7. Asparagus can be grown on soil, which has a salt content, too high for many other crops.
SOWING AND TRANSPLANTING
8-10 kg of seeds are necessary for an hectare. The seed is sown in early spring or during winter and takes 3 to 4 weeks to germinate and 8-10 weeks to produce ‘Crowns’. The rows are spaced at about 1.5 to 2 meters and 45 to 60 cm distance is kept within rows. • Male and Female Plants The cultivated asparagus is a dioecious plant, e.g. male and female flowers are produced on separate plants. In addition to dioecious plants, a small percentage of seedlings develop hermaphrodite plants.
Low growing vegetables may be grown as intercrops between the asparagus rows to compensate the expenses in the 1st and 2nd year. Cole crops, Beans, green crops etc. can be grown, provided enough nutrients are applied for both crops.
- Manures and Fertilizers Fertilizer application of 2 cwt. of ammonia, 1 cwt. of muriate of potash and 4 cwt. of superphosphate per acre besides 20 to 30 tons of well decayed dung. Highest yield on light soil from an application of 120 lbs each of nitrogen and phosphorus and 180 lbs of potash per acre, Others recommended that after the spears are harvested 25 to 35 cart-load manures together with 100 kg each of Murate of potash and superphosphate should be applied to the soil. Some growers believe that asparagus being a sea shore plant needs common salt (Sodium Chloride) for success in growing.
- Irrigation In the summer season the crop needs irrigation once a week, while irrigation is not necessary from August to January.
- Weed control Weeds between the rows can be controlled by proper cultivation. Frequent shallow hoeing keep down the weed population. After the harvest of spears a thorough cultivation should be done destroying all the weeds. The broad-leaved weeds can be controlled successfully by means of 2,4 –D before and after the harvest, avoiding spray to asparagus tops. Several other herbicides have also been used successfully to control weeds.
DISEASE, INSECT PESTS AND THEIR CONTROL
- Asperagus Rust (Puccinia asparagi) It is the most serious disease. The disease appears as reddish yellow spots on the trunk and on the trunk. It reduces the total yield and sometimes plants are killed.
- Fusarium wilt This disease is caused by a fungus (Fusarium sp.) in the soil. The affected spears develop a brown discolouration and gradually wilted and stunted. This disease although not common may severely affect a whole plantation where it occurs.
- Violet Root Rot This is a fungus disease caused by Helicoboridium purpureum. The leaves of the disease plants turn into yellow and dropping. All the disease plants along with roots should be carefully collected and destroyed.
- Asparagus Beetles The young shoots are damaged by adults and larvae. One per cent rotenone dusted on the spears will kill the beetles. This dust is also effective againest the larvae.
Harvesting is done from the 3rd year onwards. However, if the plantation is vigorous, the 1st cuttings may be done from the 2nd year after the crowns are set out. The 1st harvesting should be done within 2 to 3 weeks. ((Yield)) Yield of plantation in full harvest is on an average about 3500 to 4000 kg per hectare each year.