The demand of small-scale farmers in Kenya for cheap and readily available irrigation technology has led to the adaptation of imported sprinklers, even without the benefit of specific technical assistance. Although these sprinklers perform poorly from a strictly technical point of view, they seem to be appropriate for the conditions under which they must operate. They also appear to be an important element in the self-sustaining development of irrigation in Kenya. Yet a crucial issue remains: whether external intervention can enhance this local initiative without affecting its long-term sustainability.
A favourable context
In the past years comparatively low transport costs and a good market infrastructure, coupled with a favourable climate, have helped to expand Kenya's horticulture sector. The possibility of producing valuable crops in two dry seasons under irrigated conditions has prompted both government and private enterprise to invest in irrigation infrastructure. A myriad of small, gravity-operated, pipe-fed irrigation schemes have flourished particularly on the steep slopes of Mt. Kenya. Farmers draw water from an open furrow, from a main pipeline, or from their own domestic supply network, using one or more movable hoses, each attached to one or two sprinklers. Irrigated areas can be as small as 100 square metres and seldom exceed 1 hectare.
The schemes are characterized by diminishing flows at plot level. This results from land subdivision and increased demand for water, as well as variations in pressure according to season and time of day. Pressures rarely exceed 2 atm. but can be on the order of 0.5 atm. during peak periods. Farmers are thus forced to adapt to changing operating conditions by varying the location and size of their irrigated plots, the crops grown on them, the size of pipes used in the fields, the type and number of sprinklers used at any one time, the spacing of sprinklers, and the duration and intervals of irrigation.
The informal sector
According to the International Labour Organisation (ILO), the informal sector is associated with easily accessible activities, family ownership of enterprises, a small scale of operations, labour-intensive technology, skills acquired outside formal education channels, and the existence of a flexible, competitive and non-regulated market (Cazes 1991:67). The Kenyan government has only recently recognized the importance and potential of the informal sector (Jua Kali**1) for the economy, and only recently has adopted specific policies to encourage its development. The Kenya Development Plan of 1989-1993 (GoK 1992) specifies that the informal sector has an advantage over the formal sector for a number of reasons, including its 'creation of jobs at relatively low capital cost' and its 'contribution in order to increase the participation of indigenous Kenyans in economic activities'. However, in rural areas little has been done to promote and develop agricultural activities in the informal sector.
In early 1991 a study was carried out by Terra Nuova (an Italian NGO) in collaboration with the University of Nairobi. A number of schemes in the area of Mt. Kenya were examined in order to see which types of sprinkler were in use and under which conditions they were operating. The survey, which was aimed at assessing the importance of Jua Kali sprinklers in Kenya and at exploring possibilities for improvement, ascertained the criteria farmers use for choosing their sprinklers, and the level of development of the local manufacturing industry.
The result of the exploratory phase was the discovery of an incredible variety of models, in terms of both mode of operation and type of materials used. An attempt has been made to classify the locally manufactured sprinklers according to these two criteria.
Sprinklers could have been produced by blacksmiths, farmers and even schoolboys on an ad hoc or regular basis. Only in one case did a manufacturer, who had specialized in irrigation equipment, report sales of more than 50 sprinklers a year. It seems that most Jua Kali artisans began by repairing imported sprinklers and ended up by designing and producing their own. A variety of manufacturing technologies were found, which vary according to the tools, materials and availability of electricity in the workshops, and according to the technical knowledge and background of the artisans. Metal wires, plastic recycled materials and bottle caps joined by strips of old car inner tubes are used in remote areas. Riveting is used in areas where electricity is not available, and simple gas or arc welding is found in workshops close to urban centres.
On the consumer side, although a clear-cut decision-making process would be very difficult to define, farmers mentioned four aspects they take into account when selecting sprinklers for purchase:
Availability refers not only to the sprinkler itself, but also to repair facilities. This is important to note because some farmers may perceive a Jua Kali sprinkler to be of lower quality than an imported sprinkler, but they still choose it since they know that it will be easier to repair locally. Availability also implies the presence of a supplier or manufacturer in the area.
Comparisons between different types of sprinklers in terms of durability were impossible to make because of the variability in materials, operating conditions and length of use. Nevertheless, a very high general level of workmanship**3 was found in the area studied. Some Jua Kali sprinklers are made using gas welding to join the parts that wear out faster. This makes it easier to replace them. It also introduces a complex industrial-like process of spare-part production, and the provision of repair services, all of which has a positive effect on the durability of sprinklers and on their sales.
The fact that in many cases farmers use impact sprinklers for night irrigation and butterfly sprinklers during the day suggests that the latter perform better at lower pressures. That is, in the opinion of farmers, they cause less soil compaction and crop damage, although their use is more time- consuming since they have to be shifted every 30 to 60 minutes compared with every three to four hours for impact sprinklers. At higher pressures, the fast rotation of a butterfly sprinkler produces a fine mist that is easily carried away by the wind. A trial of Jua Kali butterfly sprinklers at different operating pressures, which was conducted under controlled conditions, showed coefficients of uniformity (Cu) consistently below 60% and as low as 30%. It is very probable that the low uniformity in the action of single sprinklers is not a relevant criterion for judging performance, since this is partly offset by the irregular pattern of sprinkler movement in the field and by the short irrigation intervals. Such flexibility in a system allows farmers to take quick action as soon as the effects of disuniformity on soil wetting and crop growth become apparent.
Conclusions and recommendations for development
The brevity of fieldwork might not have allowed the authors to fully understand the complexity of the system. Nevertheless, it is evident that sprinkler technology in the area in question has developed as a result of a continuous process of trial and error, stimulated both by access to imported products and by the demand for cheap and reliable implements that are appropriate for the conditions under which they must operate. Responding to this situation, Jua Kali were able to produce an astonishing variety of sprinklers using different materials and technologies and for different purposes.
Recently, Kenya's strategy regarding irrigation has led to the development of differentiated policies for various types of individual and community-based schemes. Emphasis has been on self-sustainable projects. Attention has shifted from the expansion of surface irrigation in flat arid and semi-arid areas, to the implementation and rehabilitation of gravity-operated, pipe-fed systems aimed at irrigating valuable crops during dry seasons. In an economic environment that already favours horticulture, the Ministry of Agriculture has improved its agricultural extension and engineering support. It has also facilitated the provision of commercial loans for both irrigation infrastructure and crop development, and has encouraged private intervention in marketing.
This policy shift in the direction of financial autonomy will certainly encourage farmers and irrigation engineers to search for low-cost, easy-to-repair technology. Expensive technology (e.g. pressure regulators) for standardizing the conditions of operation may be replaced by cheaper, though not technically 'optimal', designs. Encouraging local entrepreneurs to implement schemes and provide services should also favour the growth of the Jua Kali sector, and offer scope for improving sprinkler technology in a way that will benefit both farmers and artisans.
To achieve this, sprinklers should be looked at not as isolated products but in the context of the conditions under which they operate and are manufactured. For instance uniformity, which is crucial in conventional schemes where system layout is rigid, is not a relevant criterion by which to judge performance in situations where farmers base their decisions on their perception of wetting patterns, and where they use flexible irrigation strategies. Even manufacturers produce for different needs, with different materials, and using different skills. Attempts to standardize technology may only destroy a richness in terms of adaptability to changing conditions.
Recommended strategies include:
P.O. Box 74916
References in the text
Cazes G. and J. Domingo (1991) Le sous-développement et ses critères. Montreuil: Bréal.
Government of Kenya (1992) Sessional paper 2. Nairobi: GoK.
Bedini F., F. Gichuki, D. Masera and K. Ndugo (1993) Evaluation of Jua Kali sprinklers. Nairobi: IDB-MoA.
Masera D. (1993) Product development for the informal sector. Nairobi: Undugu Society of Kenya/SNV.
Masera D. (1993) A pictured story book on product development for the informal sector. Nairobi:USK.
**1 Jua Kali is the Kiswahili word for 'fierce sun'. It is also the nickname given to activities in the informal sector.
**2 The prices of Jua Kali sprinklers usually include a PVC riser and a metal bar to fix it in the ground.
**3 Workmanship in relation to sprinkler production refers to the capacity to
develop an implement able to achieve a specified performance using the technology and materials