Root and Tuber Crops In Kenya

Root and tuber crops in Kenya are important food crops that have gained increased importance due to their role in food security, ability to withstand drought as well as their potential for commercial processing.

Currently, the country produces 3.68M MT of Irish potatoes, sweet potatoes, cassava, cocoyams and yams. This is way below the country’s potential. For instance, the average yield for Irish potatoes stands at 7MT per ha compared to the potential of 25MT achieved under optimal husbandry practices. Some of the key challenges facing the subsector include: weak and dysfunctional stakeholder institutions, inadequate information, underdeveloped markets, inadequate quality planting materials, low processing levels, low access to financial services, insufficient applied research and technology development.

Kenya continues to face periodic food and feed shortages arising from unfavorable weather
conditions, poor husbandry practices and lack of adequate quality planting materials. Other
factors include weak farmer’s institutions and linkages across value chains, overreliance on a
limited range of farm enterprises, insufficient information among stakeholders. Smallholder
farmers also have limited access to business development services, financial services and
appropriate technology packages.

Root and Tuber Crops In Kenya

Root and tuber crops such as arrowroots are the second most important food crops after cereals that have the potential to contribute significantly to the food security needs of the Kenyan people.

Root and tuber crops are an important source of food and feed and play an important role in ensuring food security. They are grown across a wide range of Agro-ecological zones including ASALs have high level of tolerance to drought and heat and are adapted to a wide range of uses as human food, animal feed and serve as raw materials for industry. With climatic change as an emerging phenomenon and its consequences, root and tuber crops offer choices and opportunities as they exhibit higher tolerance thresholds to a variety of stresses such as water and heat stress, water salinity and the emergence of new pests.

Challenges Facing Root and Tuber Crops Farmers in Kenya

The challenges facing the root and tuber crops sub-sector are numerous and include

• weak stakeholder institutions and linkages between players in the subsector,
• low and declining productivity,
• high losses due to pests and diseases,
• lack of adequate quantities of clean and healthy seeds and planting materials,
• idle and inefficient land use, inadequate use of farm inputs and modern technology,
• low access to financial services, poor post-harvest management practices,
• low levels of processing and marketing inefficiencies.
• Declining productivity of these crops in some areas has also been caused by adverse weather conditions,
• poor soil fertility, use of low yielding varieties,
• low levels of mechanization and poor crop husbandry practices.

Root and Tuber Crops in Kenya

The major root and tuber crops grown principally for human consumption in Kenya are grown across a wide range of Agro-ecological zones (AEZs). Most of these crops are not native to Kenya but were introduced from other continents. Majority of root and tuber crops are consumed fresh. In addition, there are various processed products on the market. These include dried chips, pellets, flour, starch, Ugali, bread, juice, cookies, biscuits, chinchin, pastries, akara, crisps, soaps and  composite flours. Irish potato has been heavily commercialized compared to other root and tuber
crops.

The history and level of development of the various roots and tuber crops in Kenya is as described below.

1. Irish Potato

The Irish potato (Solanum tuberosum) originated from the high plains of the Andes Cordillera where the Incas cultivated the plant largely for food. It was imported from Europe to Africa by missionaries and thereafter by colonial administrators in the 19th Century.

The European settler farmers introduced the crop in Kenya initially in Kiambu, Murang’a and Nyeri districts in the late 19th Century primarily for domestic consumption and later, for export. Indigenous Kenyan farmers started potato cultivation in 1920 and entered the export market in 1923.

New potato varieties and seed potato production were introduced at the National Agricultural Laboratories, Kabete in 1903 and at Plant Breeding Station, Njoro in 1927. The main variety grown during that time was Kerr’s Pink.

Processing of potatoes began with the establishment of vegetable dehydration plants in Kerugoya and Karatina to meet the needs of the British armies in Northern Africa and Asia. In order to meet the increased demand for processed products, higher yielding and disease resistant varieties were imported and new cultivation areas in Meru and Molo opened up.

In 1963, the Government undertook to promote potato production in the country by introducing new varieties from Germany and through the establishment of a potato development programme in 1967, streamlined production of certified seeds and disease resistant cultivars.

In 1979 the Government through the Agricultural Development Corporation (ADC) in collaboration with Kenya Farmers Association (KFA) initiated a commercially oriented Seed Potato Production Programme to produce and distribute seed potatoes. The increased seed production in the 1980’s led to the setting up of a cold storage complex in 1985 in Molo with a capacity of 2,250 tonnes.

The ADC and KALRO (now KALRO) played a central role in the production of seed potato. However, after the 1990’s, production of seed became a challenge mainly due to subdivision of ADC and KALRO farms and their re-allocation to private individual entities.

2. Cassava

Cassava (Manihot esculentum) comprises numerous species, with the centre of origin being South America. It was introduced to Africa by Portuguese navigators at the end of the 16th century, spreading rapidly into West Africa, Central Africa and the countries bordering the Gulf of Guinea, from where it penetrated inland via the basin of River Congo into Eastern Africa. By the end of 19th Century, it was well adopted and adapted in Kenya as an important traditional food crop growing in many areas and across various agro-ecological zones of the country.

Cassava is a crop of the lowland tropics and does best in a warm, moist climate with mean temperature ranges from 25 to 29°C. Cassava does well with rainfall of between 1000-1500 mm per year; but is well adapted to cultivation under conditions of drought and can profitably be grown in areas where the annual rainfall is as low as 500mm. The crop has low labour requirement. It produces higher amounts of calories per hectare than most tropical food crops. Among the non-cereal crops, cassava comes second to Irish potato as an important source of food, and is ranking fifth after wheat, rice, maize and potatoes in the world.

Cassava is used to make gluten-free flour, animal feed, confectionary products, and a substitute of sucrose in beverages. It is also used in the laundry industry for starching of garments before ironing to give a better look. Cassava is rich in gluten-free carbohydrates, which helps to prevent gluten intolerance and food allergies. Cassava is helpful in reducing cholesterol level owing to the high amount of fiber content. It is a rich source of calcium, manganese, and iron, which is beneficial for pregnant women. Cassava is neutral in taste, and it encourages overeating by providing feeling of fullness.

3. Sweet Potato

Sweet potato (Ipomea batatas) originated from Latin America. It was introduced into many parts of Africa by Portuguese navigators in the 16th Century.

It is an important root crop cultivated throughout tropics where there is sufficient moisture to support its growth. Sweet potatoes can be grown in a wide range of agro ecological zones including low rainfall areas and has low input demand. It is a drought tolerant crop and serves as a food security crop with a high nutritive value. For instance, the orange fleshed varieties (SPK 004, kabode and vitaa) can provide sufficient daily requirements of Vitamin A. They can also be processed into juice, puree or composite flours that can be used in making baked products and weaning foods. The leaves are used as a vegetable and the vines as animal fodder.

Due to contemporary health concerns by consumers and the subsequent improvement of its food value in some varieties, its utilization as a snack and for breakfast is on the increase especially in urban areas.

4. Cocoyams (Arrow roots)

Cocoyams (Colocasia esculentum and Xanthosoma sagittifolium) popularly known as ‘Nduma’ originated in South East Asia and the Pacific islands, with the Indian subcontinent and Indonesia also being considered as the primary centres of origin of some varieties. In East Africa however, cocoyams are referred to as arrowroots.

There are more than 200 cultivars of cocoyams worldwide, selected for their edible corms or cormels, or their ornamental foliage. These cultivars fall into two main groups: wetland and upland cocoyams. In Kenya, two species of cocoyams are commonly grown for food:

Colocasia esculenta a wetland type commonly referred to as cocoyam, taro, dasheen in which the main corm provide a source of food; and Xanthosamas agittifolium an upland type commonly referred to as tannia, new cocoyam or mbiira which produce numerous corms that are used much like potatoes for cooking and in processing. These local varieties are either purple speckled or white fleshed. Their corms, cormels, stalks, leaves and inflorescence are consumed by humans. In East Africa, cocoyams have traditionally been steamed and eaten as a snack alongside beverages.

Cocoyam is generally cooked by baking or boiling. The starch contained in the large corms is highly digestible (98.8 percent) therefore making it a good source of carbohydrate and to a lesser degree a source of potassium and protein. Corms are used in the production of chips, dehydrated stable commodities, starch, flour, and in non-food application of starch in the manufacture of biodegradable plastics.

Cocoyam leaves are rich in proteins, minerals and vitamins A, B, and C and can be cooked and used for human consumption as a very nutritious vegetable, while the root is rich in carbohydrates and minerals. Cocoyam leaf blades and petioles have been used as animal feed.

Cocoyams are good for people allergic to milk or cereals and can be consumed by children who are sensitive to milk (Rothand et.al., 1967). Therefore cocoyam flour and other products have been used for infant formulae in the United States and have formed an important constituent of proprietary canned baby foods.

5. Yams

The yam (Dioscorea spp.) comprises several species of different origins such as Southeast Asia, West Africa, East Africa, Brazil and Guyana. The yam is a thick vine tuber, cultivated throughout the tropics and in parts of the subtropics and temperate zones, comprising of annual and perennial species.

The most popular edible yam species are the white yams (Dioscorea rotundata), an annual species that accounts for 90 percent of world production of about 25 million tonnes.

Yam is important for food security in East and West Africa where 95% of the world production occurs (FAO, 1991), with Nigeria as the leading producer. The tubers principally provide carbohydrates, but also appreciable amounts of vitamins, proteins and minerals.

Indeed, protein content found in some species is higher than in maize and rice. The peel of yam is rich in protein and glucose content. It can be used as a feed for small ruminants and has medicinal value. In addition, the crop adapts well to medium and high altitude climatic conditions, survives long dry spells, has flexible harvest schedules and can be stored for up to six months after harvest thus serving as a food security crop. In spite of this potential, the yam is a crop that has been ignored in East and Central Africa region.

Summary

Full exploitation of the potential of the roots and tuber crops, as a source of food, feed and
other agro-raw materials is constrained by an array of challenges ranging from institutional
deficiencies, asymmetric market and technological information and sub-optimal basic crop
husbandry practices. Of particular importance is in-availability of adequate quality clean
seed and planting materials.

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