Yam / Elephant foot yam / Elephant yam / Amorphophallus Companulatus Blume / Stink Lily / Whitespot giant arum is widely cultivated in India and is a profitable as well as popular vegetable crop. It is also called Sooran, Suran, Jimikand, Senai kizhangu, Kanda, Suvarna gedde, Panjar gedde, Surnu oal, Chena, Oluo, etc. It belongs to the Araceae family.
Yam is a tropical tuber crop consumed as a vegetable and is rich in starch. It has good shade tolerance and is easy to cultivate. Yam has the advantage of being less prone to diseases and pests and this makes it a favorite among farmers. It is a good source of protein and carbohydrates as well. Yam is cultivated in Bihar, WB, Karnataka, AP, Kerala, Telangana and Maharashtra. Some popular varieties of Yam are Gajendra, Sree Kartika, Sree Latha and Sree Padma.
Elephant foot yam is a remunerative and profitable stem tuber crop. The crop is popular due to its shade tolerance, easiness in cultivation, high productivity, less incidence of pests and diseases, steady demand and reasonably good price. Tubers are mainly used as a vegetable after thorough cooking. Yam is a hard vegetable like the pumpkin and therefore hard to chop.
The outer skin layer is coarse and hard to peel. Chips are made of starch-rich tubers. Tubers contain 18 % starch, 1 – 5 % protein and up to 2 % fat. The leaves contain 2 – 3 % protein, 3 % carbohydrates and 4 – 7 % crude fiber. Tubers and leaves are quite acrid due to the high content of oxalates. Acridity is usually removed by boiling fairly for a long time. This vegetable, unlike most others, requires longer cooking duration.
The tender stems, as well as leaves of yam, are also used as vegetables. Some dishes that are made from Yam are oal bharta, oal curry, choka, oal pickle, oal chutney, jimikand curry, jimikand sabzi, ol shaak, etc. It is widely used in Indian medicine and is recommended as a remedy in Ayurveda. It is known to be good for ailments such as bronchitis, asthma, abdominal pain, emesis, dysentery, spleen enlargement, piles, elephantiasis, and so on. It is used as an antibiotic to reduce bacterial infections.
As mentioned, yam is a tropical and sub-tropical crop that requires humid and warm climates for its vegetative growth and cool and dry climate for its corm development. It requires a well distributed annual rainfall for better yield. It is propagated through corm. They are mostly dark brown on the outer cover and white or orange inside. It needs thorough washing before being used for cooking purposes. It has a good shelf life and can be cut into cubes and stored after it is peeled. They look quite similar to sweet potatoes.
Image source – ctcri.org
Image source – ctcri.org
Process of growing Yam
⦁ Time / Season / Climatic conditions –
Yam is a tropical / sub-tropical crop and requires humid and warm climatic conditions for its vegetative growth and dry and cool climate for its corm development. A well distributed annual rainfall is also required to cultivate yam.
It undergoes a dormancy period of 45 – 60 days. Traditionally farmers take advantage of the dormancy period by planting during February – March so that the setts sprout with the pre-monsoon showers. April – May is the planting season.
⦁ Seed Rate / Spacing –
Yam is propagated through corm. An ordinary-sized yam gives about 6 – 8 bits for planting. After one or two ploughings, pits of size 60 cm x 60 cm x 45 cm are made at a spacing of 90 cm x 90 cm.
For harvesting small to medium sized tubers are used with a distance between pits reduced to 60 cm x 60 cm. Pits are half filled with top-soil and well-dried farmyard manure @ 2, 0-2, 5 kg/pit and wood ash.
The tuber is cut into 750 – 1000 g small bits in such a way that each bit has at least a small portion of the ring around each bud. Whole corms of 500 g size can also be used as a planting material. Use of cormels and minisett transplants of 100 g size as planting material at a closer spacing of 45 cm x 30 cm.
The cut pieces are dipped in cow dung solution to prevent evaporation of moisture from the cut surface. The pieces are planted in such a way that the sprouting region (the ring) is kept above the soil. About 3500 kg of corms/ha is required. Sprouting takes place in about a month.
⦁ Soil type / Land preparation / Irrigation –
Yam grows well in fertile red loamy soils with a pH range of 5.5 – 7.2. Test the soil before use.
The land is brought to fine tilth by giving a few ploughings. Form beds of convenient size. Pits are half filled with top-soil and well-dried farmyard manure @ 2, 0-2, 5 kg/pit and wood ash. Vegetable cowpea variety CO 2 is recommended as suitable intercrop in elephant foot yam. It can be intercropped profitably in coconut, arecanut, rubber, banana and robusta coffee plantations at a spacing of 90 cm x 90 cm. The half quantity of FYM (12.5 t/ha) and one-third of NPK (27:20:33) will be sufficient for the intercrop. Apply 25 tons of FYM/ha during the last plowing.
The recommended dose of NPK/ha is 80:60:100 kg. Apply 40:60:50 kg NPK/ha at 45 days after planting along with weeding and intercultural operations. Top dress with 40:50 N and K one month later along with shallow intercultural operations. Corms harvested in November should be stored in well-ventilated places. The tuber is cut into 750 – 1000 g small bits in such a way that each bit has at least a small portion of the ring around each bud. Whole corms of 500 g size can also be used as a planting material. Use of cormels and minisett transplants of 100 g size as planting material at a closer spacing of 45 cm x 30 cm.
After packing the pits with top-soil and other manures, they should be mulched with paddy straw or green leaves for moisture conservation and weed control.
It is mostly raised as a rainfed crop. However, irrigation is required when monsoon fails, where it is grown on a large scale. Water stagnation is harmful to the crop. Wherever irrigation facility is available, irrigation can be given once a week. In case of dry season or under commercial cultivation, the crop requires irrigation. In case of heavy rains, ensure the excess water is drained out as it can cause water-logging that damages the crop.
⦁ Weed management / Pest Control –
Weeding and earthing-up operations are done as and when necessary.
Leaf spot disease can be controlled by spraying Mancozeb @ 2 g/lit.
Collar rot disease is caused by a soil-borne fungus Sclerotium rolfsii. Water-logging, poor drainage and mechanical injury at collar region favor the disease incidence. Brownish lesions first occur on collar regions, which spreads to the entire pseudostem and cause complete yellowing of the plant. In a severe case, the plant collapses leading to complete crop loss.
The collar can be controlled by using disease-free planting material, remove infected plant materials, improve drainage conditions, incorporate organic amendments like neem cake.
Also, drench the soil with carbenilazim or apply biocontrol agents like Trichoderma harzianumI @ 2.5 kg/ha mixed with 50kg of FYM (lg/l of water).
Amorphophallus Mosaic Disease is spread is through planting material. Secondary spread of the disease is through insect vectors, Myzus persicae Sulz., Aphis gossypii Glover, A. craccivora Koch. and Pentalonia nigronervosa Coq.
Disease symptoms include mosaic mottling of leaves and distortion of leaf lamina. Corms produced by the mottled plants are much smaller than those without mottled leaves.
To control this, use virus-free planting material and spray systemic insecticides.
⦁ Harvesting –
Harvesting is done on 8 months after planting and particularly during January – February months. Drying of stem and leaves indicates the harvesting stage in elephant yam. The crop can yield about 30 – 35 t/ha in 240 days.
For seed purpose, the yams can be left in the field itself till planting the next crop or the lifted yams can be stored in sand or paddy straw. The tuber has an excellent shelf life and can be stored at room temperature. You can use a pickax to harvest. Alternately, you can also dig the soil for harvesting.
Ensure you wash well before use. Peeling is a tough job as the outer skin is hard and course. The vegetable takes time to cook and is usually used as a gravy.
⦁ Benefits of Yam –
⦁ Yam is easy to cultivate and has high productivity and yield
⦁ It is less prone to diseases and pests and therefore easy on farmers
⦁ It is a good source of protein and carbohydrates and omega-3 fatty acids
⦁ It helps in reducing bad cholesterol
⦁ Elephant foot yam helps patients suffering from bronchitis and asthma
⦁ It helps in reducing blood sugar levels
⦁ Yam is known to control abdominal pains and muscle spasms
⦁ Yam reduces the risk of cancer and helps in controlling weight
⦁ It also helps women in estrogen and hormonal balance
⦁ Yam helps lower blood pressure and is a good source of antioxidants
⦁ Elephant foot yam helps in liver cleansing and has low glycemic index
⦁ It is good for diabetic patients as well
⦁ It heals skin diseases and cures respiratory problems
⦁ It is a good source of vitamin B6
⦁ It supports the female endocrine system
⦁ It has a good amount of antioxidants
⦁ Yam juice is known to aid digestion and improve bowel movements
⦁ It also improves cognitive ability and is a cancer deterrent
⦁ It is a good source of energy as it contains starch and helps in RBC production
Nutritional value of yam
Serving Size: 3.5 ounces (100 grams), raw
Serving % Daily
Calories from Fat 1
Total Fat 0 g 0%
Saturated Fat 0 g 0%
Cholesterol 0 mg 0%
Sodium 9 mg 0%
Total Carbohydrates 28 g 9%
Dietary Fiber 4 g 16%
Sugar 0 g
Protein 2 g
Vitamin A3% Vitamin C 28%
Calcium2% Iron 3%
Image source – foodfacts.mercola.com