Introduction & Uses:
Asparagus (Asparagus officialis) commonly known as Kurilo in Nepali is a herbaceous annual plant. Tender shoots called as ‘spears’ are used as vegetable & in preparation of soups. The tender spear contains a white crystalline substance, ‘asparagine’ that is used in preparation of medicine as diuretic in cardiac dropsy & chronic gout. It is grown in very small area in Nepal.
The origin of Asparagus is temperate Europe & Asia. (Thompson & Kelly)
- Perennial dioecious herb with erect branches.
- Crown is made of roots & rhizomes.
- Aerial stem (spear) arises from bud of rhizome.
- Female plants produce berries with 1-3 seeds per fruit.
In early days, Mary Washington variety was popular in Nepal. New cultivar nowadays is American jersey king which have short duration & better taste.
Climate & Soil:
It prefers sandy silt loam or alluvial soil with pH ranging from 6-7.5 & rich in organic matter. Since it is temperate crop, it requires temperature of 15-18 degree Celsius for spear production. A low temperature of 10 degree Celsius is necessary during dormant season for 60-90 days. Altitude should be above 1000 m from sea level.
Manuring & Fertilization:
Well decomposed FYM or compost of 30-40 tons/ha during field preparation is mandatory. The recommended dose of fertilizer is 80: 60: 40 kg NPK/ha. Full dose of P & K is applied with FYM at planting whereas nitrogen is applied in 4-5 split dose i.e. during planting, 20-25 days after planting, & after 1st, 2nd, 3rd cutting of spear. Requirement of nitrogen is higher during first year but it decreases during the coming year.
Propagation & Planting:
It is propagated through seed or crown of 2-3 months old. 3-4 kg of seed is required to raise seedling for planting in one hector of field. Sowing is done during March to May in Hills and July to November in plains where seed germinate within 3-4 weeks. Sowing should be done at 30 * 4-6 (cm * cm) spacing in nursery whereas during transplanting spacing is maintained at 70-75 * 50 (cm * cm). seedlings are kept in nursery for 6-8 months.
One -year old crown with good health are selected for propagation through crown. Spacing for this propagation is 1.5-2 * 45-60 (m * cm) in furrows with firmly pressing around the crown.
Irrigate the crop immediately after planting & then regularly at 10-15 days interval. Shallow hoeing must be carried out to keep weed under control. Make sure that young sprouts are not damaged.
It is carried out to obtain white spears. The soil is molded to a height of 20-25 cm over the rows to blanch the young spear so that white spear for canning can be obtained before harvesting.
Harvesting & yield:
The spear arises from bud on the rhizome 6 months after planting of crown or seedlings. The spear should not be harvested up to 1 year after planting crown because of active growth of root system & rhizome during this period. Growth of spear depends on food stored in root during previous year. So sufficient time must be provided for root growth & food storage. First cutting should be carried out after 2 years. For the first cutting, cutting period must be limited to only 2-3 weeks & 8-12 weeks in the subsequent years of regular harvesting. Asparagus knife should be used to cut the spear just below the ground surface. During cutting care should be taken so as not to injure the corresponding spear.
Average yield per year is 4-7 q/ha.
Spears are made into bunches & carried to sheds, where grading, trimming, washing & packing in crates are done. The spears cab be stored at 0 degree Celsius and 90% RH for a period of 3-4 weeks.
Insect pest: Most common insect pest of asparagus plant are as:
- Asparagus beetle:
- Remove the affected spears.
- Spray Malathion @ 0.1 % at regular intervals.
- Golden centipede
- Remove the affected plants.
- Flooding the field.
- Destroy the debris of the previous crop.
- Locate resistant varieties.
- Uproot the affected plants and destroy them.
- Spray Dithane M-45 or Dithane Z-78 at 0.2%