Asparagus, the hardy, branching, herbaceous plant, is a very succulent vegetables. Its numerous branchlets and very fine delicate foliage make the tops valuable for decorative purposes.
The current supply of asparagus is largely imported and still not enough to meet increasing local demand.
Asparagus was previously regarded as a temperate climate crop, growing best in cool areas, Thus, its cultivation was limited to places like Baguio and Mountain Province.
However, new tropical varieties which can be cultivated in warms areas like Metro Manila are now available. Mass production of the crop is possible in tropical sites, but only few people have gone into its commercial production outside of the traditional area. Growers are found in Tarlac, Nueva Ecija, Pampanga, Quezon, Bukidnon and Albay.
A business venture in asparagus production could be very rewarding. A plantation composed of 16 to 18 one-by-ten meter plots could yield a net income of P177,045.60 after two years.
In terms of nutritive value, asparagus has 32 per cent calcium content, 30 per cent phosphorus, plus other vitamins and minerals. Unfortunately, because of its prohibitive price, it is not popular with low income families. It is served as regular fare in hotel, restaurants and airline caterers which supply the food requirements of transients and resident foreign nationals.
The standard varieties is the Mary Washington which has large shoots and allows long cutting. This strain can be harvested early and is very productive.
The Martha Washington variety is more resistant to asparagus rust than the Mary Washington, but both have high commercial quality.
The palmetto is another rust-resistant variety and it also grown to some extent.
Asparagus grows best in soil that is deep, loose and light. It demands high fertility, plenty of organic matter, good drainage and an abundant supply of moisture. It grows well areas where rainfall is evenly distributed throughout the year, like Marinduque, Oriental Mindoro, Bondoc Peninsula, Bohol, Sulu, Misamis Occidental and eastern part of Cagayan, Isabela and Nueva Ecija. It is also grows well in dry areas where water supply is constantly available. The desired average daily temperature of the area should be 53oF to exchange the growth of the spears.
Asparagus can be propagated sexually and asexually. Asexually propagation involves slicing separating a part of the groove down the roots, taking care not to break the stalks from the rhizomes or the underground stems. Some of the spears must be allowed to grow to increase the groove for propagation. The groove should not be allowed to become thick because this will prevent the growth of some spears of new stalks.
Sexual propagation involves the following:
Make sure that the soil is free of clods. Set the areas at one by ten meters, then add composed mixed with the garden soil.
Soak the seeds in ordinary water at room temperature for two or more days until the outer head covering start to crack. Wash the seeds at least twice a day. Then dry the seeds and plant at once.
Sowing in seedbed.
Apply complete fertilizer (14-14-14) to supplement the food element in the soil. Handrail the seeds, one seed per hill, at 8 to 10 cm between hills and about 1 to 4 cm deep. Maintain a moist seedbed by thorough watering. Shallow cultivation and hand-weeding are a must. Keep the Seedbed moist for six months to one year before transplanting.
Inspect the seedbeds daily to check at the earliest time the occurrence of pests and diseases. Spraying of pre-emergence herbicides at recommended rates is necessary.
Plow and harrow the field twice and alternately to obtain a good soil tilt, with a depth of 20 cm or deeper on deep alluvial soil. Irrigate the field for an appropriate moisture level. Make furrows 30 cm wide and 15 to 25 cm deep. The distance between seeds should not be less than 125 cm for unbalanced or white asparagus. The spacing should be increased when the crop is grown on good silt-loam or muck (peat).
Apply three bags of urea (45-0-0) just before transplanting at pressured distance. Dig and lift the crowns from the seedbeds using a short-handed fork and transplant as soon as possible. The crowns are planted buds up, at least 15 to 33 cm deep but should not be covered over 5 to 8 cm of soil at planting time. The crowns are spaced 60 to 90 cm apart within the rows. The rate of the seedling should be 16,000 to 18,000 per hectare. Plant one seedling per hill on the ridge. Irrigate between the furrows after transplanting.
Cultivation and care.
Keep the area free from weeds. Hand- hoeing may be done during the cutting times. Every year after the first, it is best to disk and harrow thoroughly before the growth begins.
If a white blanched asparagus is grown, a very low ridge on the furrow is suitable.
At the end of the cutting season, the asparagus bed should be thoroughly cultivated, the ridge leveled with an off-barring disk harrow.
Fertilizer application depends on the soil types. For unmannered sandy and sandy loam soil, 100 lb. each of nitrogen and phosphoric acid are needed. For silt-loam or light soil, 125 lbs of phosphoric acid and 160 lbs potash can be applied. Split application of urea at the rate of five bags per hectare every two months is also preferable. One may include 2 to 3 trucks of chicken dung per hectare before the last harrowing. The same amount can be applied on succeeding years. It is also recommended to used about 350 kg of composed mixed with 400 kg of complete fertilizer (14-14-14) per hectare. Two-thirds of the amount should be applied every year before the rainy season and the remaining amount the start of the dry season.
Pest and disease control.
The only known asparagus pest in the Philippines is the mealy bugs. They are controlled by cutting and burning the infected portions and spraying the plants every two weeks with Sevin at the rate of one or two tablespoon per gallon of water.
The disease called Asparagus rust is characterized by small reddish-yellow spots on the main stem and on branches. To minimize chances of occurrence, plant resistant varieties of asparagus like the Argentuil and Reading Giant. One can also spray the plants while still moist with dew with lime sulfur at the manufacturer’s dosage.
Another disease, the fusarium root rot, is one that builds up on the soil and persists for many years. To prevent this, the resistant strains of asparagus, such as the Martha Washington and waltham Washington could be planted.
The fusarium wilt, on the other hand, results in brown discoloration on the surface of the spears which become stunted. So far, there is no known effective control for this, except to use crowns that were raised on disease-free beds.
Furrow-irrigate every five days to maintain optimum growth of spears during the dry season.
The period harvesting and cutting season differ in various section of the country. The spears may be harvested at an earlier age where the growing season is long, relatively cool, and the rainfall is evenly distributed. Where the growing season is short and warm, spears should be only harvested after the crowns have had two full years of growth. Harvesting is usually done on the 13th month of operation.
Asparagus can be harvested for a period of 270 days within a year. While seedling are still young, the first harvest period could yield about 10 kg per day per hectare for 30 days. Cutting should then be stopped for a month and then resumed the following month for the second harvest. The yield could then be 20 kg a day per hectare for 60 days.
For the succeeding harvest periods, cutting should be done for three consecutive months followed by a month of rest. The average yield this time could be 40 kg a day per hectare.
Insert an asparagus knife along the side of the shoot 2 to 5 cm below the soil surface. Move the handle outward to form the cutting angle and severe the spear with a sharp thrust. Green asparagus should be cut 9 to 10 inches longer at least half of a length above the ground. The spear should not be closer than two inches from the crown to avoid injury to the developed buds of the rhizomes.
Although the asparagus may remain fairly attractive inappearance in several days, its quality deteriorates fast warm temperature. It should therefore be sold within 12 to 24 hours after harvesting, unless refrigerated.
When it has to be kept overnight without refrigeration, submerge the tied branches almost to their tips in ice water.
Fresh asparagus may also be stored for a limited period. After cutting, prickle the spears at 40oF. A high relative humidity of 95 per cent should be maintained to prevent moisture loss.
Shoots may be marketed either in bundles or loose in varieties of containers. Bundled asparagus are packed to weight of one kilogram or 500 gm. They must be adequately protected to preserve their freshness, to prevent damage and to kept clean.
The bundled are often wrapped in parchment paper or cellophane with only the tips and the base showing. This improves the appearance of the asparagus when placed upright. Wood can also be used as containers. Supplies from Europe are packed in fiberboard pyramidal containers.
Asparagus in Your Backyard
Asparagus, often regarded as rare and expensive, can be a regular part of the Filipino meal. By planting them on a yard scale, small farmers can enjoy large benefits.
Asparagus can be harvested 200 days a year and sold at fumigate price of P45 a kilo, and a supermarket price of P70. A yield of two kilos a week can be acquired from about 75 plants.
Demands for this vegetable is high, with the country importing an average of P20 million worth of asparagus every year. In Metro Manila alone there a 25-hectare gap of production for the demand which is roughly 5,000 kilos a day.
Asparagus can be cooked like any ordinary vegetable. It can be steamed and dipped in mayonnaise, or made into soup. It can be suited with onions and ground pork, and cooked in a variety of other recipes.
The best variety to be grown in the country is the Martha Washington, which adjust well to the climate.
The “male” asparagus plant, with relatively long flowers, produces more spears or shoots. The female plant, on the other hand, produces more seeds. Flowers of the female plants are circular and small.
To reduce initial cost of production, one can start from seeds. These can be bought at a farm price of one peso per gram from local producers of asparagus, as well as from the Bureau of Plant Industry. A gram of seeds can yield 74 plants.
Starting from seedlings, however, will mean harvesting sooner. They can be bought at a farm price of P25 each.
Seedling can be planted in used plastic or tin cups for six months, and then transplanted to be exposed to field conditions for another six months to one year. For easier transplanting, keep the crowns or the seedling small by applying no fertilizer until they are already on the field, arranged in plots.
When planting seeds, plant five seeds per hill and, upon transplanting, split the grown seedlings at the base at five separate plants.
Allow only three canes or stems to grow on each hill so more spears can grow. Cut the canes of the male plants after they have already sent out pollen to fertilize the females.
Support weak stems by tying them to bamboo stakes, and also to prevent the crowns below from being shaken by the wind.
To harvest the seeds, squeeze them out of the pods when they are already red and mature, then dry them for a few days.
Harvesting the spears is done 200 days a year. Rest periods are allowed during summer or when irrigation is not available.
Asparagus reaches 10 to 15 years of maximum productivity. After the twentieth year, dig out the plant, split the canes at the base, and replant them.
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