root and tuber crops.pptx vvu
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Root and tuber crops
cocoyam
petiole
corm
cormel
• Cocoyams (Colocasia and Xanthosoma spp.) are stem tubers that are widely cultivated in both the tropical and subtropical regions of the world.
• the two species mostly grown in West Africa are Colocasia esculenta and Xanthosoma sagittifolium
• Cocoyams can be processed into several industrial inputs, food and feed products, similar to products from potatoes in the Western world.
• The processing of the crops include boiling, roasting, frying in oil, pasting, milling and conversion into ‘fufu’, soup thickeners, flour for baking, chips, beverage powder, porridge, and special food for gastro-intestinal disorders
uses
• Cocoyam leaves are used in many homes as a leafy vegetable (pot herb) and can also be fed to poultry as greens
• It is also reported to be one of the most promising forages because of its re-growth capacity, high yield and palatability.
• leaves could be fed to growing pigs, while the petioles are considered to be more appropriate for feeding to pregnant sows, which need lower levels of protein in the diet and are able to tolerate bulky feeds as well
uses
• The Neat Food Company, uses cocoyam to make fufu flour
• Akwaba Food Company which exports chopped cocoyam leaves and chips to Europe
Nutritinal value
• The young leaves and petioles which are occasionally used for food contain about 23% protein on a dry weight basis.
• They are also rich a source of calcium, phosphorus, iron, Vitamin C, thiamine, riboflavin and niacin, all of which are important constituents of the human
Importance
• In Ghana the crop is grown on a small scale and usually as an intercrop together with cocoa, plantains, oil palm and cassava.
• Evidence exists that although cocoyam is cultivated on a small scale, it has been able to contribute significantly to the national food baskets. They also serve as a source of income for many families
adaptation
• Xanthosoma Sagittifolium is a tropical rain forest plant and requires an annual rainfall of about 1800mm per annum.
• It prefers a well drained soil with pH 5.5 – 6.5 (Owueme, 1991). Although in their natural habitat they grow under the forest canopy
• they can be cultivated in areas with full exposure to sunlight (Owueme, 1991).
• • Most tuber crops including cocoyam grow and yield well in
soils that are ploughed to a depth of about 20-40cm especially on clay soils.
Cultivation of the crop
• Planting materials• The major planting material for cocoyam is the main
stem (corm), although cormels can also be used. • Selected corms are cut into pieces of about 100 to
200 grams with each piece having at least a bud (Karikari,1971).
• For rapid field multiplication, fresh, healthy cocoyam corms and cormels are cut into pieces of about 5 to 10 grams (microsetts
•
• treated with (fungicide) and• nursed in black polybags containing steam-sterilized 2:1
top soil: sand potting mixture• Plantlets developed by the rapid field technique are
kept under shade for about three months before they are planted out in their permanent fields.
• Planting materials raised from microsetts during the dry season and planted at the onset of the rains yield about twice more than plants grown from 100-200g cut corms at the beginning of the rainy season (Osei, 2003).
Fertilizer application
• When cocoyams are grown in high moisture regimes, fertilizers applied to them are subjected to leaching and should therefore be applied in split doses.
• The first application is done at planting whiles the second application is done three or four months after planting (Owueme and Sinha, 1991).
Fertilizer application
• Most farmers in tropical Africa cultivate cocoyam without applying any chemical fertilizers.
• They rely mostly on the native fertility of the soil, which is very high when virgin forest is used to establish cocoyam.
• They may sometimes place compost or farmyard manure in the planting holes before planting
HARVESTING AND STORAGE
• Cocoyam is ready for harvesting after 9-11 months after planting. Maturity indicator for cocoyam is yellowing of the leaves.
• For. X saggitifolium, multiple harvesting is done thus only the cormels are removed at each harvest while the corm is left to produce new generations of cormels, which will be harvested latter.
• Harvesting is usually by hand or hand tools. Alternatively the crop may be ploughed out after which the corm and cormels are picked manually.
HARVESTING AND STORAGE
• Cocoyam can be stored for up to four months when kept under 7oC at a relative humidity of 85% (Owueme and Sinha, 1991).
• Storage under high temperatures increases respiration, rotting and sprouting, shortening storage life of cocoyams.
• Too low temperatures also cause corm decay (Owueme and Sinha, 1991).
• Traditional storage methods include storage in underground pits or on open platforms. Some farmers also leave the crop in the field and harvest it as needed
processing
• Cocoyam chips• Cocoyam flour• Fufu• Chopped leaves• dried petioles for silage
Cassava grater
