Yam or ubi is one of the country’s “famine crops”. It is grown backyard and commercial farms. Distinguished from tugui known as the lesser yam, ubi or the greater yam has fleshy underground roots used as staple food in the provinces. Among rootcrops, it ranks fourth among the widely-cultivated.
Yam is perennial climbing herb with flesh color ranging from white to yellow, orange, red and deep purple. A side from being known a vegetable, it is famous as halo-halo ingredients, and a source of flour. Other food products such as dehydrated yam flakes and instant yam mixes can be derived from yam. Yam peelings or waste are fed to poultry and livestock.
Production of yam in the country reached 17,540 metric tons in 1985 with Central Visayas producing the greatest volume. Total production was valued at P57.6 million and covered a land area of 6,980 hectares. Most farmers plant this crop in May and June, while those in Pampanga and Pangasinan plant from October to December.
One of the most common yam varieties is the ubing kinampay. It has five types namely, original kinampay– characterized by red-purple flesh, kabus-ok–with white flesh and large roots, tamisan–reddish-white fleshed and sweeter in taste, Binanag– with creamy, white flesh and elongated root, and Binato– with big, hard roots and white and flesh.
Another variety, ubing kalamay, stands out as the “most palatable.” It is extensively grown in Bohol which has sandy, lime-soaked soil suitable for this variety. It has deep purple flesh and extra large-size roots.
Ubi thrives in dry humid places with light- textured soil, preferably sandy loam or silt loam soil with good drainage. for best results, plant at the start or at the end of the rainy season when the adequate moisture can be obtained. Ubi growth favors low and medium altitudes with temperature ranging from 25-30°C.
Plow and harrow the land thoroughly in 2 to 3 weeks intervals. Pulverize the soil to a depth of 25 cm.
Ubi is propagated by means of setts, which is the upper part of the root nearest the stem. A few days before planting, cut these into pieces containing 2 to 3 buds and weighing 250 grams each. Treat them with wood ash or any fungicide to protect from fungus.
Methods of planting according to the kind of soil, climate and topography of the land. In areas where the ground is flat, simply bury the setts a few centimeters below the ground, then cover with mulch. This method is appropriate for unusually soft and deep soil, such as those in river-flooded plains.
During the rainy season, planting on mounds and ridges is advisable. Draw the top soil into mound or pile them into long continuous ridges one meter apart, high enough to have deep loose soil. It should also be broad enough not to erode easily. Ubi planted on the ridge is said to produce higher yields.
In areas with stony soil, planting in trenches or holes is preferable. Dig large hole and fill with soil organic matter. This is best done during April and May planting seasons. Plant setts in trenches 75 cm apart and 10 cm deep. Orient them in such manner that their cut portion face either upward or downward. With this distancing, about 13,333 setts are needed for a hectare.
Cropping System with Yam
Yam can be grown in crop rotation with short-season crops. It is often planted during the first season after land clearing. The bush fallow system of cropping involves both rotation and intercropping. Yam is usually planted in rotation with cassava, and intercropped with melon, maize or okra. Suitable alternate crops with yam are ground nut, cowpea and other legumes which improved the soil.
Being a vine, the yam plant needs stakes or support. As soon as the plants emerge, place stakes 2 to 2.25 meters tall for each plant. These can be made from bamboo poles, dried ipil-ipil stems or madre de cacao.
Apply pre-emergence herbicides like Diuronat the rate of 3 to 3.5 kg per hectare to prevent the growth of weeds. Hand weeding is also recommended. Apply nitrogen potassium fertilizers one month after plants have emerged.
Yam beetles which burrow into the roots can be controlled by dusting the setts before planting with Aldrin at the rate of 30.2 kg per hectare. Gamalin or various BHC preparations can also be used.
Control beetles larvae which feed on the leaves and shoots by spraying Sevin 85 and Agrocide 3. When infestation is light, simply hand-pick the infested leaves.
Pest that attack stored tubers can be stopped by disinfecting the setts before planting. Dip them solution of Gamma BHC or Heptachlor. Spray growing plants with 0.25% Malathion emulsion. Similarly, treat the tubers’ storage place with insecticide.
Ubi for harvest 10 months after planting, when leaves have become dry. Loosen the soil around the roots and carefully lift the vines and cut off the tubers. Average yield yam is 20 to 58 ,tons per hectare.
Set aside planting materials for the next planting season. It is good practice to store the rest of the produce to be able to command higher prices when the demand for the crop is at its peak and the supply is low.
Store the tubers in a well-ventilated place and keep them dry. Blemished or damaged roots must be eliminated or treated with wood ash.
Yam can be stored in yam barns, which are made of vertically arranged wooden poles and palm leaf midribs. The poles should be three meters high and arranged 50 cm apart, held together by horizontal wooden sticks and vertical logs dug into the soil. Tie the stored roots to the poles with the rope or twine.
Yam can also be stored in raised platform three feet from the ground. Place the roots horizontally on the platform and not on the top of one another.
Another method of storing yam is to bury them in a ditch covered with soil. Cover the area with coconut leaves. Check the stored roots regularly and provide ventilation.
Yam can also be kept in cold storage. Keep them on shelves in rows with the temperature nit below 10°C.
Avoid storing “wounded” or cut roots. To prevent fungal infection, cure the roots a few days before storing in an area with the temperature of 29-32°C and a relative humidity of 90 to 95 per cent for four days. One may also dip them in Benlate or Captan, or in 250 ppm Thiabenzole
To prevent rodents and other pest from attacking stored yam, securely fence the barns or storage areas or use traps and baits.
Yam farmers usually sell their produce to retailers, wholesalers and end-users at the farms, roads sides and public markets. Big farmers enter into contact farming for ready market for their produce.
Suggested Calendar of Activities for Ubi Production
Activity Approximate date:
- Land preparation 2nd to last week of April
- Preparing seedbeds Last week of April
- Preparing setts Last week of April
- Mulching First to 2nd week of May
- Preparing stakes 2nd week of May to first week of June
- First weeding 3rd week of June
- Replanting Last week of June to 1st week of July
- Staking 1st to second week of July
- First training of 2nd week of July vines
- First spraying 4th week of July
- First fertilizer Last week of July application
- Second spraying 1st week of August
- Second weeding 3rd week of August
- Third spraying 3rd week of August
- Second training Last week of August/1st week of September
- Fourth spraying Last week of August/1st week of September
- Fifth spraying third week of September
- Second fertilizer last week of September application
- Sixth spraying last week of September
- Covering exposed first week of November tubers
- Selecting pros- last week of November pective sett source of plant
- Constructing/ first to 2nd week of November repairing storage barn of vines
- Harvesting hauling 2nd week to 4th week of December tubers 24. Removing stakes last week of December/ first week of January
- Treating damaged first week of January tubers, storing
- Inspecting stored 3rd week of January to third week of tubers April
Companies that Buy Ubi Tubers
San Miguel Corporation
6766 Ayala Avenue, Metro Manila
P.O. Box 271,Manila
M.E. Jimenez Enterprises 3rd Floor Sagittarius Bldg.
H.V. dela Costa Street
Salcedo Village, Makati,MM
Vulcan Industrial and Mining Corporation
8th Floor, Quad Alpha Centrum Bldg.
Pioneer st., Mandaluyong, MM
source: region10.dost.gov.ph, photo from bakerri.blogspot.com