Sweet potatoes are packed with numerous nutrients. That is why it is called a super food. This sweet potato is grown well in almost all temperate regions including India, Bangladesh, Nepal, Bhutan, Pakistan, America, Africa. Although not one of the major crops in our state West Bengal, sweet potato cultivation is quite profitable. Written by Bidhan Chandra Agricultural University, Crop Science Department researcher Sushmita Moi And Bappa Mondal. (Read the last part)
Scientifically the method of cultivation of this sweet potato is discussed below-
Suitable land and soil
Sweet potatoes can be grown in almost all types of soil. But loam and sandy loam soils are good for sweet potato cultivation. Also land drainage system should be added. Soil acidity should be between 6.0.
Among the improved varieties of white sweet potato in our state West Bengal are Vidhan Jagannath, Pusa Safed, Kalmegh, Sribhadra, Samrat, Shankar etc. Also among the red/orange colored varieties Gauri, ST-14 and Kamala Sundari of Vidhan Chandra Krishi University etc. are quite popular. (Source: All-India Integrated Tuber Crops Research Project, Vidhan Chandra Agricultural University).
[আরও পড়ুন: পুষ্টিগুণে ভরপুর, মিষ্টি আলু চাষই আয়ের দিশা দেখাচ্ছে কৃষকদের ]
The month of Kartik (mid-October to mid-November) is the best time for sweet potato cultivation. Sweet potato vines or raw seeds, sweet potato tubers are required for sowing sweet potato seedlings in one acre of land. For sowing cuttings or cuttings, 25,000 to 30,000 sweet potato cuttings or 35-40 kg of tubers are required per acre. 1st and 2nd cuttings should be planted from the vine head. Distance from row to row is 60 cm and potato/vine to potato/vine is 30 cm. Rows should be planted in a flat manner so that 2-3 feet are under the soil.
Each piece should be 25-30 cm long. Agar chunks (with agar buds) give the highest yield. If the Agar block is available, the middle block should not be fitted. Older pieces should not be used as seeds/cuttings. Care should be taken while planting the middle part so that the root side is planted in the ground.
600 grams of Urea, 500 grams of TSP, 730 grams of Mop and 40 kg of cow dung are required per century. Cow dung fertilizer, full amount of TSP and urea and MOP. One fourth of the fertilizer should be mixed well in the soil at the time of sowing and the rest of the urea and MOP fertilizers should be applied along the row two months after sowing.
Irrigation methods and maintenance
It is a drought tolerant crop, but needs to be irrigated 2-3 times depending on soil moisture. Sweet potato fields should be kept weed free until they are full of vines.
Leaves, buds and stems
This disease is caused by the fungus called Alternaria bataticola.
The disease spreads through infected vines, alternate hosts and wind. Rainy, humid and cold weather favors the growth of this disease. Fungal spores are produced on infected leaves and are then spread from one plant to another by wind. This disease is usually more common on old and mature leaves. Attack of the disease causes circular brown spots on the leaves covered with rounded borders. Many spots coalesce to form large spots.
As the spots get older, the affected leaf tissue breaks down and leaves drop.
Spots are also seen on stems and leaf buds, the spots enlarge and surround the stem.
Remedy of the disease After harvesting the leaves of the affected plants should be burnt. Healthy, vigorous and germ-free vines should be used. Crop phase should be followed in the field. As soon as the spots appear on the leaves, fungicides of eprodione group (eg Rovral 50 WP) 2 g per liter of water or fungicides of difenaconazole + azoxystrobin group (eg Amister Top 325 SC) mixed at the rate of 1 ml per liter of water and every 7-10 days 2- 3 times should be sprayed on the tree.
Soft rot disease
This disease is caused by the fungus Rhizopus nigricans. The disease spreads through infected tubers. Water-soaked spots appear on potatoes as a result of this disease attack. In this disease, the tissue in the affected area is destroyed very quickly. Affected potatoes quickly rot from both ends, becoming soft and moist, with foul odors. A thick layer of white mycelium can be seen on the surface of infected potatoes. Besides, black colored fruiting body of the pathogen is also seen.
After harvesting the affected leaves should be burnt. Care should be taken during lifting, transportation and storage of tubers from the ground to avoid injury to the tubers. Tubers should be well cured before storage. To reduce this disease, select cut and crushed tubers and save only perfect tubers. After storing potatoes, the room should be well ventilated. Potatoes should be stored in relatively cool and dry weather.
/Charcoal rot disease
This disease is caused by the fungus Macrophomina phaseolina / Diplodia natalensis. Germs survive on abandoned plant parts and spread through wind, water and insects. Under the attack of this disease, the tree is stunted and yellow in color. Later the affected tree gradually turns black. This disease is also seen in tubers in storage. Black spots are caused by this disease on the tuber. Later rotting starts and the entire tuber rots.
Disease free sweet potato vines should be planted. Crop phase should be adopted. Carbendazim group fungicides (such as Autostin) or Carboxin + Thiram group fungicides (such as Provax 200 WP) should be mixed at the rate of 2 grams per liter of water and the vine should be dipped in it and applied to the ground. To protect the stored tubers from attack of this disease, the tubers should be well cured before storage. To reduce this disease, select cut, torn and bruised tubers and save only perfect tubers.
After harvesting, Mancozeb group fungicides (eg Dithen M45) should be mixed at the rate of 1 gram per liter of water and sprayed on the tubers and stored. Leaf curl or leaf curl virus disease This disease is caused by the attack of leaf curl virus. This disease is spread by whitefly. Potato leaves become severely shortened in this disease. Sweet potato leaves curl upwards. Yields are severely affected.
Disease-free vines should be planted. The land should be kept clean. For control of whitefly, insecticides of Diafenthuron group (eg Pegasus 50 SC) should be mixed at the rate of 1 ml per liter of water and sprayed 2-3 times after 7-10 days.
Insects and remedies
Other insects are minor except for one insect called the weevil. Adult weevils damage tubers by burrowing curved tunnels inside them. Weevil-infested tubers become inedible. In this case, this insect can be suppressed if the soil is raised at the base of the sweet potato plant. Infected sweet potatoes should not be kept with good potatoes. Cypermethrin type insecticide (eg Ustad 20 ml or Magic 10 ml) should be mixed with every 10 liters of water and sprayed 2/3 times every 10-12 days.
Yield per hectare
Sweet potatoes can be harvested within 120-140 days after planting. Usually the yield per acre is about 80 to 90 quintals. Yields may vary from location to location. It depends on the variety or cultivation method, soil conditions and climate. According to the demand of this delicious crop sweet potato, the current market price is around Tk 30-40 per kg. About 35,000 to 40,000 rupees are spent on one acre of sweet potato cultivation. After deducting the cost of cultivation, the farmers can earn about 3 times Rs.
Canning Sweet Potatoes
This potato preservation process is very similar to the local method of round potatoes. Fresh/bruised/thornless potatoes should be stored. It is better to spread the tubers in the shade and cover them with vine leaves for a few days before storing them. Sweet potato matures in about 90-120 days. Then when its shell is scratched, thick white milky juice comes out. In this situation, before monsoon comes, it is necessary to cut the vines and pick potatoes well with plough/spade. For storage, spread a 3- to 4-inch layer of sand on the mound or loft, place a layer of sweet potatoes 28 to 30 inches high, and cover with another 3- to 4-inch layer of sand. In this way, several layers of sweet potatoes are protected from the sweet potato weevil.
[আরও পড়ুন: চাষের জমিতে রাসায়নিকের অপব্যবহারে ক্ষতির সম্ভাবনা, মুক্তির পথ দেখাচ্ছে জৈব কৃষি ]
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