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| R Number: R7132 |
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| Contractor: HR Wallingford | Dates: July 1998 to March 2001 |
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Objective Identify technical, socio-economic and institutional constraints faced by peri-urban, irrigated agriculture and propose measures to sustain and enhance productivity, whilst minimising risks to human health and the environment. Background Although many agencies engaged in Urban and Peri-urban Agriculture (UPA) stress the importance of water as a production input, there is little detailed information available describing the use and management of this resource. To address this knowledge gap the British Government’s Department for International Development (DFID) funded this research project to obtain quantitative and qualitative information on the productivity and constraints of irrigated, peri-urban agriculture. Research was carried out over three years within a 40km radius from the centre of Kumasi, Ghana and within a 20 km radius from the centre of Nairobi, Kenya. Within these zones, pressures for land use change and the associated problems of insecurity of tenure and rising land values are confined to areas close to the city, but other urban influences – markets, services, input supply and resource pollution – are present throughout the zone. Methodology The studies included the following activities:
Results The extent of informal urban and peri-urban irrigation and income generation The extent and importance of informal, irrigated, peri-urban agriculture appears to be generally under-estimated in government statistics. Data from both cities show that informal irrigation is widely practised by individuals generally acting without support from government or NGO’s, and is the primary source of cash income for over 80% of households involved. In the 40km radius around Kumasi there are estimated to be 12,700 households irrigating at least 11,900 ha. In the smaller study area around Nairobi (only ¼ that of Kumasi) at least 3,700 households irrigate 2,200 ha. To put this in perspective the total, formally irrigated, area reported by the Government of Ghana is just 6,400 ha. (Kenya reports approximately ten times this area with 66,600 ha, (FAO, 1995)). Unlike other forms of urban and peri-urban agriculture, which are often valued for their direct contribution to family food security, access to irrigation facilitates production on a more commercial basis, generating a cash income. However, as yields are often low and the areas cultivated are small, returns remain low. Average family income generated from informal irrigated agriculture in Kumasi, where irrigation occurs over approximately 5 months (December – April) was $US 153, with the best performers achieving almost $US 360. In Nairobi, where irrigated production continues through the whole year, average annual income generated from informal irrigated agriculture was $US 279. Gender In Kumasi, 86% of those managing an irrigated plot are men – by tradition women are engaged in production of household food crops, with men controlling cash crops. By contrast, the majority of irrigators in Nairobi (66%) are women. Age and time irrigating The average age of farmers in Kumasi is 37, and most are ethnic Asantes. These data tend to refute the suggestion made in earlier studies that intensive vegetable farming around Kumasi is a specialised activity carried out by young male migrants, farming on a "hit and run basis", moving to new areas when soil fertility reduces. Most farmers engaged in IUPIA are neither young nor migrants, and there is little evidence that migrant farmers are quicker to move on than indigenous farmers. Expansion of the area under informal irrigation has only occurred recently. Over 60% of villages report that the number of farmers practising dry season irrigation has increased significantly over the last 10 years. In Nairobi, the average age of peri-urban farmers is 36, and 49% have been irrigating for 4 years or less.
Other occupations 90 % of those practising irrigated cropping describe it as their "main" occupation and in approximately 60% of cases irrigators report no second occupation. In both areas, 84 % of farmers listed irrigated vegetable production as the primary source of household income. Rainfed farming ranked second in importance as an income source in Kumasi but was insignificant as a source of income for households involved in IUPIA in Nairobi. Wealth In both Nairobi and Kumasi, irrigators tend to be classed, by their own communities, as having "average" or "above average" wealth, but it would be wrong to conclude a causal relationship between practising irrigated production and improving wealth status. It is more likely that because of the financial resources needed to engage in irrigated vegetable cropping, the opportunity is only open to such families. Although judged by their communities’ own standards to be of "average wealth", urban and peri-urban irrigators are still poor when judged by international standards. Income per head amongst Kumasi irrigators’ households may be as low as 14 US cents per day, if it is (conservatively) assumed that irrigated cropping provides only half the total household income. This figure is well below the international poverty indicator of $US 1/head/day. A striking finding in Kumasi is that just over half those questioned are paying cash to rent land. As cash rental is not a feature of traditional Ghanaian farming systems these results indicate that customary land tenure arrangements are being transformed. The average rental cost is $US 15/ha/month although there is large variation around this mean. Cash rental is much less common in Nairobi – only 15% of the farmers surveyed rent land and the average monthly charge is $US 6/ha/month. Illegal squatting is widespread in Nairobi (39% of respondents) but there is little evidence that squatters are being regularly harassed or moved on. The greater availability of land and water in the villages around Kumasi leads to larger average holdings of 0.9 ha. In the more urban context of Nairobi, where pressure on land is greater and water more scarce, holdings average just 0.6 ha. The same factors lead to greater mobility between plots in Kumasi than is seen in Nairobi. Shallow groundwater drawn from dugouts is the most common water source in Kumasi but this is seldom available around Nairobi where the main sources are rivers and abstraction from sewers – a water source used by 36% of farmers included in the surveys. There are important differences in the conveyance methods used in the two study areas. In Kumasi "conventional" surface irrigation methods are not used, all irrigation is by overhead means, with water normally carried from the source in buckets and applied with watering cans. In Nairobi, use of open earth channels is commonplace. The use of motorised pumps is evident in both cities although in Kumasi only 5% of farmers own a pump, compared with 33% in Nairobi. However, occasional rental of pumps is more widespread in Kumasi. Seasonal irrigation applications in Kumasi were found to be low. Farmers who make occasional use of pumps to supplement manual carrying applied an average of 1.1 mm/day over the dry season. Those irrigating only manually applied as little as 0.25 mm/day or less. It is likely that crops were exploiting water already held in the soil either from the previous rainy season or from permanent, shallow groundwater. The little irrigation that was applied assisted in early crop establishment and slowed the rate of depletion from the soil profile. In Nairobi, where the annual rainfall is much lower, irrigation applications were much higher, averaging about 3.5 mm/day, though depths of application varied between sites and according to the method of water conveyance. The hours of labour devoted to irrigation in the two cities reflect this pattern. In both locations irrigation was the greatest consumer of labour but in Nairobi this amounted to 1,530 hrs/ha (191 person-days/ha assuming 8 hrs continuous irrigation); whilst in Kumasi labour spent in irrigation was just half this at 860 hrs/ha or 107 person-days/ha. Cropping practices and yields In Kumasi, the quality of land preparation varies greatly between sites. In the majority of cases the natural vegetation is cleared away leaving a broken and uneven surface with a coarse tilth into which seedlings are transplanted. In a few cases, well-formed, flat-topped, raised beds are prepared with space between beds giving access for weeding and watering. Plot preparation and crop management generally appeared to be of a higher standard in Nairobi. The most widely grown irrigated crops in Kumasi are, in descending order, tomato, garden egg, okra, hot pepper and cabbage. In Nairobi the most common are kale, tomato, spinach, maize and cabbage. Yield data obtained for tomato, garden egg and okra in Kumasi indicate that yields are low. Data collected in Nairobi suggest that while yields there are below the "expected range with good management" they are better than those seen in Kumasi. Direct comparison is only possible for tomato. In Kumasi the average yield was just 2.4 t/ha while in Nairobi it was 11.6 t/ha. The picture emerges of households investing heavily in human and financial resources to grow irrigated vegetables but due to poor cropping practices and frequently limited water supply, yields are poor, although a cash profit is still possible. There appears to be a clear need for improved extension advice to growers alongside actions to improve water supply and management. Farm budgets The detailed farm budget studies showed the average cost of production in Kumasi to be $US 215/ha, with labour costs making up 57% of this total. The average profit, after costs were deducted from revenue, was $US 337 /ha. (The actual profit figure was $US 153 as the average plot size in this detailed study of 21 farmers was 0.46 ha). Access to a perennial water source and regular hire of a motorised pump does not lead to improved profitability – slightly improved revenues are more than outweighed by much higher production costs. Farmers making profits substantially above these average values generally achieved average or above average yields for their dominant crop, but the greatest factor influencing their profit was the ability to sell consistently at above average prices. Better than average agronomic skills are not sufficient to ensure higher profitability – they must be matched by good marketing skills. In Nairobi, detailed farm budget studies were carried out on just six farms and there was great variation in both costs and incomes across those six such that simple, average values would be misleading. The farm with the greatest profit of $US 1,380 also had the greatest costs, totalling $US 418. (This is equivalent to a profit/ha of $US 9,678 and expenditure of $US 2,923). This farm lies in the west of Nairobi where the water is relatively clean and it was the largest of the plots studied in Nairobi. However, location and access to water is no indication of actual profitability. The two farmers at Thiboro, in western Nairobi, with cleaner water, larger and better laid out plots returned the highest and lowest profits/ha of the sample. The two farmers at Maili Saba, using highly polluted water on small hillside plots to the east of Nairobi secured the second and fourth highest levels of profit/ha in the sample. Paid labour was only used on the two larger plots to the west of Nairobi. In both cities individuals market produce – neither formal nor informal marketing groups have met with much success. Kumasi farmers are more inclined to transport some of their produce to market than is the case in Nairobi. In both locations individual consumers and traders buy produce from the field, though field sales to consumers are much more widespread in Nairobi than Kumasi. The Nairobi farmers do not rank marketing as a serious constraint to their enterprises – in constraints ranking it was last. By contrast, the producers around Kumasi ranked marketing as a major constraint, coming second only to credit provision. This is a consequence of the complex marketing arrangements involving "market queens", travelling traders and central market traders who, between them, control prices paid to farmers. The farmers see themselves as being exploited by this well-entrenched system but have been unable to act against it, either individually or collectively. In Nairobi, credit of any kind is seldom used and its absence is not regarded as a constraint. However, for growers around Kumasi, credit provision and marketing are strongly linked as the traders and market queens are widely used as a source of informal credit. Although this credit attracts no interest and requires no formal collateral it ties the grower into an exclusive agreement with the trader to sell all produce through them. Targeted water sampling programmes were carried out in both cities to obtain basic data on the quality of water being used by irrigators. This information was compared with microbiological water quality guidelines set by the World Health Organisation (WHO), to provide an indication of the scale of risk to irrigators and consumers. There appears to be little risk to irrigated crop production from the concentrations of heavy metals observed in Kumasi. In Nairobi, the concentrations of manganese and some other heavy metals could be toxic to plants and may pose an indirect threat to human health, although guidelines are lacking. The data from Nairobi show generally very high levels of microbiological pollution. Numbers of faecal coliform in the Nairobi River to the east of the city centre are similar to effluent drawn directly from sewage mains at Maili Saba, and 19,000 times greater than the WHO recommended limit for unrestricted irrigation. Only the shallow well at Thiboro, upstream of Nairobi City, yielded water that lies close to the WHO guidelines, and even this exceeded the threshold on two sampling dates. In Kumasi, levels of pollution are generally lower with two sites upstream of the city centre lying on or about the WHO threshold value and even the worst site, downstream of Kumasi, exceeded the guideline by only 90 fold. Risks to the health of irrigators who come into regular contact with these waters are beyond dispute. Where fresh salad and other vegetables likely to be eaten raw are irrigated there is also a clear danger to consumers. Even where produce is cooked before consumption, there remains a risk of disease transmission from the handling of dirty crops. Quantitative data on consumers’ use of vegetables – cooked or eaten raw – and the distribution of crop types relative to water quality, remains to be obtained. It is not easy to identify simple interventions that are likely to be acceptable to growers, consumers and municipal agencies. Many growers depend on the use of polluted water to sustain their livelihoods and any action to ban or restrict their production is unlikely to be effective. Possible policy and technical interventions are reviewed in section 11. Farmers’ perception of constraints In Kumasi, the shortage or unavailability of credit is the outstanding constraint identified by all farmers, irrespective of their irrigation method, followed by marketing and access to water. Concerns over the unavailability of labour or land are of least concern for all farm types. For the majority of farmers reliant on manual carrying of water for irrigation, access to water is the second greatest constraint after credit. 80 to 85 % of the farmers questioned believe they are constrained by their water supply – they cannot apply as much as they would like, their yield is affected by water shortage or water supply limits the area they cultivate. In Nairobi, obtaining an adequate supply of water is the primary constraint. Obtaining other inputs, such as seed and agro-chemicals, is also a serious constraint. As the farms included in this study are close to the urban centre, theft of crops and equipment and damage to crops are also significant issues. In contrast to Kumasi, neither credit nor marketing is ranked as a significant constraint. Water quality Programmes aimed at reducing the health risks associated with irrigated urban and peri-urban agriculture must be broad-based, with technical interventions and institutional change working in parallel. They must provide an incentive for producers and consumers to change current practices and make change possible, without those groups incurring high additional costs. The technical and institutional resources needed to eliminate the use of polluted water for crop irrigation by informal irrigators should not be underestimated. Raising the awareness of producers and consumers of the health risks associated with the use of polluted water for vegetable irrigation can provide an incentive for change amongst consumers, traders and growers. Traders may be encouraged to maintain improved levels of hygiene in the storage, washing and presentation of produce – avoiding the use of dirty water to freshen produce. To achieve this market traders must have easy access to clean water supplies. The traders may also pass on the demand of consumers to growers, seeking only to buy produce from farmers using clean water. Where farmers are pressed by traders to supply "clean" produce or where premium prices are paid for "safe" produce they have an incentive to use clean water sources. However, alternative, cleaner water sources must be available to them and if premium prices are to be paid, consumers need some form of assurance, through a system of certification, that produce has been grown using clean water. The provision of clean water sources is a major challenge. Water drawn from shallow wells or dugouts might be expected to be less polluted than that in rivers draining urban centres, but the studies in both cities showed the mean faecal coliform count in all monitored wells to exceed the WHO guideline for unrestricted irrigation. There is a need for field research to determine if simple protection measures, combined with awareness raising amongst farmers, can raise the water quality from these wells to a level that consistently lies within the WHO guideline. In the short term, to provide existing irrigators with a water source of improved quality, some form of simple and low cost treatment must be available at the point of use, i.e. after water is abstracted from the watercourse and before application to the crop. Actions such as short term retention of water in pools and the current practice of holding water in field side drums before applying it to the crop merit further evaluation to determine their effects on levels of pathogen die-off. Approaches such as these merit research and field evaluation with farmers, but actions must be low cost, or, where this is not possible, the farmer must be able to receive a premium for the financial and labour investments made in cleaning the water supply. This can probably only be brought about through awareness raising campaigns and effective crop certification programmes. Improved water availability In Kumasi, 70% of irrigators stated that the physical effort or the cost of paying labour limited the amount of water applied to crops. In Nairobi, only 12 % of respondents said that the effort of irrigation limited their cultivated area, whilst 24% referred to the water source drying up. Thus, in Kumasi, the effort of irrigation severely constrains production while in Nairobi water scarcity is a greater constraint. There appears to be considerable potential in Kumasi for demonstrating and evaluating the acceptability to farmers of low-cost water lifting devices such as treadle pumps. These pumps can reduce the drudgery and effort required of those carrying water, and considerably improve the productivity of irrigation labour. Unlike motorised pumps, they can be used in combination with shallow dugouts – one of the most common sources of water. There was no evidence in either city of small dams being used by communities or farmer groups to retain water for dry season irrigation. Construction of such dams requires adequate technical supervision in site selection, dam design and construction, but these skills exist within the public and private sectors. It should not prove too difficult to use these agencies to implement such an intervention to improve the availability of water for urban and peri-urban irrigation. However, attention would need to be given to determining if irrigators would welcome such intervention, which would have to be managed on a communal basis. The number of technically appropriate sites may be limited in some localities but small dams are certainly an intervention worthy of further evaluation by both government departments and NGOs. Improved agronomic practices Knowledge of good agronomic practices, from the preparation and care of nursery beds, planting densities, weed and disease control, and water management through to the maintenance or improvement of soil fertility by use of manures, compost and inorganic fertilisers, is generally poor amongst urban and peri-urban irrigators. Developing and promoting good extension materials and establishing farmer groups to receive and evaluate extension advice is probably one of the most effective short-term interventions, with the objective of increasing productivity and improving farmer income from informal irrigation, that is available. Credit This was only an issue in Kumasi, where existing, formal micro-credit provision through the Poverty Alleviation Fund is widely discredited as being too politicised. While communities shared a common opinion that the vegetable farmers should co-operate to strengthen their bargaining powers in obtaining formal financial assistance, there are only a few cases where this approach had been successfully adopted, and formation of groups was not received very enthusiastically by farmers at the project workshop. Improved access to credit could be provided through formal and semi-formal micro-credit arrangements purposely tuned for IUPIA and channelled through the banks or well-established NGOs. Impartial monitoring and control would be essential to ensure that the facility achieves its purpose.
Marketing Again, marketing is only seen as a constraint in Kumasi. There is potential for farmers to work together to plan production schedules to coincide with periods of price peaks but more particularly to regularly obtain and compare price information from several market centres. Where farmers can avoid being "locked in" to selling into a single market, access to such market information, provided it can be coupled with access to traders from the alternative markets, could enable farmer groups to exploit regional variations in supply and demand of fresh produce. Formation of farmer co-operatives capable of negotiating better prices with the traders and market queens is an obvious option but has proved difficult to achieve in practice, and this suggestion was not received very enthusiastically by farmers attending the Kumasi workshops Key conclusions The studies have led to the following key conclusions:
Publications Cornish et al, (1999) Water quality and peri-urban irrigation: An assessment of surface water quality used for irrigation and its implications for human health in the peri-urban zone of Kumasi. OD/TN 95. HR Wallingford Ltd. Sept 1999. Cornish GA and Aidoo JB, (2000) Informal irrigation in the peri-urban zone of Kumasi: Findings from an initial questionnaire survey. OD/TN 97. HR Wallingford Ltd. March 2000 Hide J and Kimani J (2000) Informal irrigation in the peri-urban zone of Nairobi, Kenya: Findings from an initial questionnaire survey. OD/TN 98. HR Wallingford Ltd. March 2000. Cornish et al, (2001) Informal irrigation in the peri-urban zone of Kumasi: An analysis of farmer activity and productivity. OD/TN 103. HR Wallingford Ltd. February 2001 Hide J, Kimani J and Kimani, (2001). Informal irrigation in the peri-urban zone of Nairobi, Kenya: An analysis of farmer activity and productivity. OD/TN 104. HR Wallingford Ltd. April 2001. Hide J, Hide and Kimani,J (2001) Informal irrigation in the peri-urban zone of Nairobi, Kenya: An assessment of surface water quality used for irrigation. OD/TN 105. HR Wallingford Ltd. April 2001 HR Wallingford, (2001) Informal peri-urban irrigated agriculture: Opportunities and Constraints. Proceedings of a workshop held at KNUST, Ghana, 7 – 9 March 2001. HR Wallingford Ltd Cornish GA and Lawrence P (2001) Informal irrigation in peri-urban areas. A summary of findings and recommendations. OD 144. HR Wallingford Ltd. November 2001 HR Wallingford, (2002) Informal irrigation in peri-urban areas. Institutional aspects and options for improvement. HR Wallingford Ltd. October 2001. Collaborating organisations Institute of Land Management and Development, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Smallholder Irrigation Systems Development Organisation, (SISDO) Nairobi, Kenya | |