3. FARMING SYSTEMS IN KENYA AND THEIR AGROFORESTRY POTENTIAL

3.2 The farming systems and their agroforestry potential

The tea-based system

Tea-based systems are located on the higher slopes of the highlands in Kiambu, Nyeri, Muranga, Kirinyaga, Embu and Meru in the central highlands and in Kericho, Nandi, Kakamega and Kisii in the western highlands. This land-use system has the highest capacity for generating income from tea growing and dairy production, which are the main commercial activities. Temperate fruits and vegetables also do well in this system. Maize is the main food crop, but due to the high altitude there is only one growing season per year. Soils are of volcanic origin and tend to be acidic. Some areas have very steep slopes and V-shaped valleys.

Constraints in the system are acidic soils, low temperature and erosion problems.

Agroforestry considerations: Both land and labour have high opportunity costs. Therefore any agroforestry intervention must use little space and its management must not take time off the labour required for agriculture. Since dairy production could expand with increased fodder production, growing of fodder trees would be a viable option, but due to the high altitude and acidic soils the choice of species is limited. Calliandra calothyrsus is one of the few promising species for fodder production in this zone. Other promising interventions are boundary planting, windbreaks, woodlots, fruit orchards and live fences. Again, the low temperatures limit the choice of species. In addition to Calliandra, Morus alba can also be grown for fodder and fruit up to about 2,000 m.a.s.l. Temperate fruits such as pears, peaches and plums do well, and Croton megalocarpus can be grown on boundaries for live fencing and /or fuelwood production. It can be combined well with Grevillea robusta for timber. Casuarina cunninghamiana, Millettia dura and Hakea saligna can be planted as windbreaks, and good wood lot trees for this zone are Eucalyptus globulus and Acacia mearnsii.

The coffee-based system

Coffee-based systems are found on the lower slopes of Mt Kenya (Kirinyaga, Embu, Meru), the Aberdares (Nyeri, Muranga, Kiambu) and Mt Elgon (Bungoma). Marginal coffee zones are also found in Siaya, Machakos and the Taita Hills. These are the most intensive systems and the areas concerned have the highest population densities in the country. Coffee is important for income generation and the main food crops are maize, beans, bananas and potatoes. Dairy farming is also important and most farmers have planted fodder in small plots or as grass strips along contours. Fruit trees are intercropped with food crops, and many farmers have planted trees for fuelwood, timber and poles along boundaries, dispersed in cropland or occasionally in woodlots. Due to the intensity of land use, woodlots with competitive trees are gradually being phased out and replaced with trees that grow well with crops in other spatial arrangements, notably Grevillea. Several studies have indicated that the woody biomass in this system has increased in recent years and tree growing is an important commercial enterprise.

Constraints in the system are declining soil fertility due to continuous cropping, soil erosion, shortage of fodder and wood.

Agroforestry considerations: Agroforestry is already extensively practised in this zone. Land and labour have high opportunity costs, so agroforestry extension must be geared towards technologies that intensify the system. Boundary planting, trees along soil-conservation structures, trees dispersed in cropland, .woodlots on land that is unsuitable for cropping, live fences, fodder banks, and fruit orchards are all current practices in this system, but there is still scope for more tree growing based on such technologies. Moisture is seldom a severe constraint, hence hedgerows of nitrogen-fixing shrubs could also have potential. Due to the high altitude, however, there are few species to consider. Calliandra calothyrsus, Leucaena diversifolia and Chamaecytisus palmensis (tree lucern, tagasaste) may be good options, but experience with these species is still limited. Other important species in this system are Jacaranda mimosifolia on boundaries, and Syzygium spp. producing good wood and fruit along water courses and as windbreaks. Cyphomandra betacea (tree tomato), Persea americana (avocado), Macadamia tetraphylla, Passiflora edulis (passion fruit), Casimiroa edulis (white sapota), Annona senegalensis (custard apple), Psidium guajava (guava), Eriobotrya japonica (loquat), pawpaw, peaches and bananas are also useful for fruits or nuts. Some trees that commonly grow in cropland are Grevillea robusta, Albizia spp., Erythrina abyssinica, Cordia abyssinica, Croton spp., Markhamia lutea and Bridelia micrantha. Eucalyptus spp., Acrocarpus fraxinifolius and Acacia mearnsii are good trees for woodlots on sites where they will not interfere with more valuable production. Calliandra, Moras alba, Grevillea and Markhamia lutea are good options for planting on soil-conservation structures.

The pyrethrum-potato system

Pyrethrum-potato systems are high-altitude systems found in Meru, Nyandarua, Kiambu, Narok, Kericho, Nakuru and Uasin Gishu. Pyrethrum is produced as a cash crop and vegetables such as carrots, peas, cabbage, kale, potatoes and temperate fruits are important. Dairy production and rearing of sheep are also important activities. Part of this system consists of new settlements formed from the sub-division of former large-scale farms. Thus farmers have also introduced maize, although it does not do very well. These areas are mostly open plains or gently sloping land and trees are scarce.

Apart from the poor supply of wood products, constraints are crop damage by low temperatures and wind and the slow growth of trees.

Agroforestry considerations: Windbreaks are important both for crop protection and as one way of increasing the supply of wood products. Woodlots, boundary planting, trees on soil-conservation structures, live fences and intensified fruit production are other technologies that could be further promoted. Some suitable species for this system are Eucalyptus globulus, Acacia mearnsii, Grevillea robusta, Hakea saligna, Croton macrostachyus, Dombeya spp., Dodonaea angustifolia, Casuarina cunninghamiana, and Dovyalis caffra. Fruit trees such as pears, peaches and plums can also do well.

The maize-and-dairy system

Maize-and-dairy systems are found mainly in or near the Rift Valley: Trans Nzoia, West Pokot, Nandi, Uasin Gishu, Nakuru, Kericho, Narok and around Loitokitok. Although maize is grown throughout Kenya, in this system it is produced as a cash crop, occupying about 60% of the cropland. Dairy production is well integrated into the system, sometimes as a commercial enterprise. A significant area of this system consists of small farms sub-divided from former large-scale farms.

Constraints: The lack of trees in the newly settled areas has led to crop damage from wind and a shortage of wood products. Small-scale farmers also experience shortage of fodder, and with the increasing prices of inorganic fertilizers the maintenance of soil fertility is becoming increasingly difficult. Soil-conservation structures are often damaged by contractors ploughing across them. Post-harvest grazing is common, and burning of crop residues also occurs. Such practices are constraints to tree growing in cropland.

Agroforestry considerations: Small woodlots are already common. Some windbreaks remain from the large-scale farming era, but they are insufficient and overgrown. Wind damage can be reduced by establishing new windbreaks, but often boundary planting is more practical in small-scale farming areas and it serves the same purpose. Live fences can contribute to improved grazing practices (paddocking, etc.) on large-scale farms and they help protect homesteads and control post-harvest grazing in small-scale farming areas. Since maize is sensitive to shade, there is only scope for trees in cropland if they are intensively managed. Hence small woodlots are likely to continue to be used for intensive wood production. Trees may be used on soil-conservation structures to make them more permanent, but with due consideration to the risks of reducing crop yields because of the effects of shade. More fruit trees and vegetables could be grown both for domestic use and for sale. Some suitable species are Grevillea robusta, Sesbania spp., Croton macrostachyus, Croton megalocarpus, Acacia abyssinica, Eucalyptus spp., Acacia mearnsii, Casuarina cunninghamiana, Dovyalis caffra, Markhamia lutea, Cordia abyssinica, Calliandra calothyrsus, Combretum spp., Terminalia spp., and a large variety of fruit trees.

The wheat-dairy system

Wheat-dairy systems are located in Meru, Laikipia, Nyandarua, Samburu, Narok, Nakuru, Baringo, Uasin Gishu and Trans Nzoia. Wheat and dairy production are the two main commercial activities. Sheep also play an important role in some areas. Most small-scale farmers also grow maize, beans and vegetables for subsistence although these crops do not do very well. Sub-division of land is continuing and this will further reduce the area under wheat.

The constraints in this system are similar to the ones in the maize-dairy system.

Agroforestry considerations: Windbreaks, trees on boundaries, woodlots, live fences, fodder trees, trees on soil-conservation structures and fruit trees are all viable options for further extension in this zone. Some suitable species are Acacia abyssinica, Eucalyptus spp., Grevillea robusta, Casuarina spp., Morus alba, Calliandra calothyrsus and a large variety of fruit trees.

The subsistence food crops systems

These systems are found mainly in western Kenya in Kakamega, Bungoma, Busia, Siaya, Kisumu, Nandi, South Nyanza and Kisii, but also around Marsabit. These are high-potential areas, but due to poor infrastructure, especially poor access to markets, production for sale is not well developed. The main crops grown at present are maize, beans, bananas, cassava, sorghum, sweet potato and millet. The majority of farmers have some livestock.

Constraints are shortage of cash income and low crop yields due to low levels of management.

Agroforestry considerations: Technologies to improve soil fertility would be important and labour is not as much of a constraint as it is in the more commercially oriented systems. Fruit and fodder trees should be promoted. Some suitable species are Leucaena leucocephala, Calliandra calothyrsus, Sesbania spp., Grevillea robusta, Casuarina spp., Markhamia lutea, Albizia spp., Cajanus cajan, Erythrina abyssinica, Fkus sycomorus, Morus alba, Psidium guajava, Tipuana tipu, Syzygium spp., Maesopsis eminii and fruit trees such as citrus, pawpaw, mango and others.

The sugarcane-based system

Sugarcane-based systems are found in the Lake Basin plateau at medium altitudes (Siaya, Busia, Bungoma, Kakamega, Kisumu, Nandi, Kisii, and South Nyanza). Production of crops other than sugar is still at subsistence level. A significant land area previously devoted to other crops has now been converted to sugar production. The land has the potential for intensified livestock production, but infestation by tsetse fly is a major constraint.

Other constraints are declining soil fertility due to continuous cropping and, in some parts, soil erosion problems aggravated by tractor ploughing. Wood products are in short supply.

Agroforestry considerations: Wood production is important and could be intensified through trees on boundaries, woodlots and tree fallows with Sesbania sesban. The latter practice would also help improve soil fertility. Fruit trees could diversify the system. Some suitable species are Leucaena leucocephala, Sesbania sesban, Flemingia macrophylla, Gliricidia sepium, Albizia spp., Cajanus cajan, Ziziphus spp., Citrus spp., Mangifera indica, Annona senegalensis, Carica papaya, Pithecellobium dulce, Euphorbia tirucalli, Cassia siamea and Psidium guajava.

The cereal-grain-legume system

Cereal-grain-legume systems are found on the lower slopes of Mt Kenya adjacent to the coffee-based system (Kiambu, Muranga, Embu, Meru), and in Machakos, Kitui, Taita-Taveta, Nyeri and in the Lake Victoria basin. Production is mainly for subsistence, although surplus food crops are sold for cash. Cotton, sunflower and sisal have potential as cash crops, but marketing is still poor. Many farmers from the coffee-based system are moving to these areas.

The main constraints are low crop yields due to poor management and crop failure due to unreliable rainfall. Grazing lands are degraded due to overgrazing and poor management, and soil erosion is a problem on sloping land. There is a decline in fuelwood supply due to clearing of bushland for cultivation.

Agroforestry considerations: Trees along soil-conservation structures to make them more permanent, trees on boundaries and scattered trees in cropland are potential technologies for increased wood production and as a support to agricultural production. Hedgerows of leguminous shrubs may be less feasible due to the risk of moisture competition with crops. Woodlots have a role to play in wood production, and fodder trees are needed as a supplement for young stock and draught animals. More fruit trees of improved varieties could also be grown, both for domestic consumption and for sale. Some suitable species are Leucaena leucocephala, Flemingia macrophylla, Gliricidia sepium, Sesbania spp., Faidherbia (Acacia) albida, Grevillea robusta, Casuarina equisetifolia, Prosopis spp., Cajanus cajan, Acacia spp., Combretum spp., Terminalia spp., Faurea saligna, Cassia spp. (both exotic and indigenous), Piliostigma thonningii, Parkinsonia aculeata, Balanites spp., Cordia sinensis, Ziziphus spp., Anacardium occidentale, Citrus spp., Mangifera indica, Carica papaya, Annona spp., and Euphorbia tirucalli.

The livestock-cereal system

Livestock-cereal systems are found in Eastern Province (Meru, Embu, Machakos, Kitui), in Kajiado, and in the coastal hinterlands (Kwale, Kilifi, Tana River, Lamu). Ideally, only drought-tolerant crops should be grown in this system, but due to subsistence requirements the main food crops are still maize and beans. Other crops are pigeonpeas, cowpeas, sorghum and millet. Livestock are an important component.

Constraints to crop production are moisture limitations and little use of manure or fertilizers which results in poor soil fertility. Serious degradation of grazing land due to overstocking and poor land management is common throughout these areas. There is also a shortage of poles and timber. It can be noted that in Kwale and Kilifi Districts child mortality is high and nutritional status is among the poorest in Kenya.

Agroforestry considerations: Improvement of soil fertility is much needed, and trees and shrubs could play a role if combined with water harvesting. But consideration must be given to the risk of moisture competition with crops. Planting of more fodder trees, the establishment of fodderlots and better management of grazing areas would increase fodder availability, which would benefit both livestock and crop production (through draught animals being in better condition). Woodlots could be established mainly for production of poles, and more fruit trees could improve nutrition. The species that are suitable for this area are the same as for the cereal-grain-legume system.

The cashew-coconut system

The cashew-coconut system is found along the coast. This system has a low cropping intensity and low levels of management. Coconut, cashew and mango are the main cash crops. Some farmers in Lamu District grow cotton. The main food crops are maize, cassava and cowpeas.

Constraints are related to increased population pressure due to an influx of people from the hinterland. Shifting cultivation is practised but fallow periods are too short Intensification of land use is to some extent hindered by the tenure situation which is characterized by absentee landlords. Crop yields are low not only because of low soil fertility but also due to weed competition and a high incidence of pests and diseases. A poorly developed livestock component is the result of tsetse infestation, and shortage of wood products is another constraint

Agroforestry considerations: Improvement of soil fertility and reduction of weed populations can be achieved through hedgerow intercropping or trees dispersed in cropland. Due to high humidity, moisture competition is not a major problem. Other viable options are intensified growing of trees for shade and fruit around homesteads and wood lots for pole production. In some places more trees are needed to act as windbreaks, and where tenure is secure timber production could also be intensified. Growing of tree products for sale also has a good potential. Some suitable species are Leucaena leucocephala, Gliricidia sepium, Casuarina equisetifolia, Conocarpus lancifolius, Moringa oleifera, Azadirachta indica, Sesbania grandiflora, Prosopis spp., Acacia spp., Parkinsonia aculeata, Ziziphus spp., Ximenia americana, Cocos nucifera (coconut), Anacardium occidentale (cashew), Citrus spp., Mangifera indica, Pithecellobium dulce, and Artocarpus heterophyllus (jackfruit).

Group-ranching systems

Group-ranching systems are found in West Pokot, Elgeyo Marakwet, Baringo, Samburu, Narok and Kajiado areas of the Rift Valley Province. Livestock keeping in this system is still mainly for subsistence. User rights to grazing lands are communal, but in some parts group ranches are rapidly being sub-divided. The importance of crop production varies from one area to another, and livestock normally serve as a form of saving to cover for poor crop years. Trees for browse are an important source of fodder. In some areas, sub-divided ranch plots are sold to people from other areas who tend to be more oriented towards farming than the original inhabitants.

Constraints are erratic and insufficient rainfall resulting in inadequate soil moisture. The tenure situation constrains grazing management and production and results in land degradation and shortage of feed. The erratic and scarce rainfall and high termite populations are constraints to tree propagation.

Agroforestry considerations: Most important is protection of the existing vegetation, either individual useful trees or on preservation of trees in protected plots. Tree planting is possible, but obstacles are tenure, scarcity of water for seedling production and erratic rains during the planting season. Direct seeding can also be done but it carries the risk of failure in poor-rainfall years. Active planting or seeding of trees should normally focus on trees for fodder, shade or fruit. When the tenure changes from communal to private ownership the scope for active propagation of trees increases. Live fences then also become important. This area also has the highest potential for development of beekeeping in the country. Some suitable species are Acacia spp., Azadirachta indica, Prosopis spp., Parkinsonia aculeata, Balanites aegyptiaca, Cordia sinensis, Piliostigma thonningii, Psidium guajava, Tamarindus indica, Ziziphus mauritiana, Phoenix dactylifera and, where termites allow, Eucalyptus camaldulensis, Casuarina ecjuisetifolia and Grevillea robusta.

The communal pastoral system

Communal pastoral systems occupy a major part of Kenya's land area: Turkana, Samburu, large areas in Eastern and North-Eastern Provinces and the interior of Coast Province. Production is for subsistence and the infrastructure is very poorly developed. Communal user rights extend over large areas. Water is the most limiting factor.

Figure 3.2 The communal pastoral system

Apart from the lack of water, constraints are fodder shortage and land degradation, especially near water points and around towns. Possible range-management measures are hampered by the tenure system and overstocking: social and environmental conditions are such that these factors are not easy to change quickly.

Agroforestry considerations: Good management of existing vegetation in grazing areas and near rivers is essential since active tree propagation is difficult. Along rivers and close to bomas, individual trees for fodder, fruit or shade may be planted or protected for young livestock or milking herds. Fruit trees can be grown in irrigated areas and nitrogen-fixing trees can also play a role in increasing soil fertility in irrigation schemes. A shortage of wood that may occur near irrigation schemes can be alleviated by growing trees such as Prosopis spp. or Leucaena leucocephala, but with due consideration to the risk that they might become weeds. This tendency can be controlled to some extent by intensive management Some suitable species are Acacia spp., Prosopis spp., Balanites spp., Cordia sinensis, Cordeauxia edulis (ye-eb), Conocarpus lancifolius, Dalbergia melanoxylon, Lawsonia inermis, Tamarindus indica, Azadirachta indica, Phoenix dactylifera, and Hyphaene compressa.

Other observations

The areas where small-scale farmers were resettled after the mid-1960s pose special problems regardless of the agro-ecological zones in which they occur. In the higher potential areas, settlements were based on the former large-scale foreign-owned farms which, for reasons dealt with in Chapter 2, had their tree cover removed or confined to certain areas. The incoming farmers found themselves in areas that had very few trees.

People migrating into previous ranching areas initially found themselves in a different situation compared to those moving into large-scale farming areas. Their first need was to open up land for cultivation. Later, the need for tree products and services arose. In both situations, the in-coming settlers would, in most cases, have migrated from high-potential areas where tree planting is a common practice. It does not, therefore, require a lot of effort to convince these farmers of the need to plant trees. In most cases, they have already started doing this and the woody biomass is on the increase. The problem is, however, similar to that encountered with agricultural crops in that people tend to grow what they were used to growing in the areas from which they migrated regardless of the suitability of such crops for the new sites. Similarly, various tree species may be planted in the wrong environment partly because of lack of information on suitable alternatives.