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close this bookCERES No. 075 (FAO Ceres, 1980, 50 p.)
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The economics of the bamboo tubewell

Dispelling some myths about appropriate technology

By Edward Clay

The bamboo tubewell is one of the most interesting recent technological developments in Indian agriculture, providing a classical example of 'indigenous' or 'adapted' technology that proponents of appropriate technology have been seeking. Inevitably, it has attracted the myth-makers and those looking for an upbeat story about rural India, who have described the "invention" of the bamboo tubewell in terms reminiscent of the deeds of the great inventors.

One purpose of this article is to dispel such unhelpful myths by showing that the development of the bamboo tubewell was the culmination of widespread innovative activity to realize the economic opportunities offered by a technology introduced in a form inappropriate to local conditions. It also questions the soundness of analyses that see small farmers as the prime beneficiaries of low-cost or "fractional" technologies. The real significance of the bamboo tubewell phenomenon, when considered in the context of widespread adaptation of irrigation technology in the Indian subcontinent, is that it demonstrates the need to commit resources to research and development on agricultural engineering technologies comparable to those expended on crop technologies.

In the Kosi area of Bihar, India, tubewell irrigation was first promoted by government programmes intended to increase agricultural production. In the late 1950s, there was limited initial local response mainly among a few large landowners. However, when the droughts of the mid-1960s coincided with the appearance of the new hybrid wheat seeds and the Intensive Agriculture Areas Programme, there was a new campaign to sink wells with direct government credit and a 50-percent subsidy on investment costs. The combination of high food-grain prices, new varieties with greater yield potential and low-cost credit coincided with a substantial increase in tubewell investment. The windfall profits that a few farmers made during 1965-67 were frequently cited as the conclusive demonstration of the potential of tubewell irrigation.

Techniques chosen for public credit-supported programmes for tubewell investment failed to consider local physical or socioeconomic conditions. The official package consisted of 10- or 15-cm diameter wells, iron casing with a brass screen, sunk to a depth of about 45 m or more. A small number of peripatetic rigs controlled by the Minor Irrigation Directorate sank all the wells. These rigs employed a slow and expensive percussive drilling technique. Transport costs and delays multiplied as each rig had to move long distances by bullock cart to sink perhaps only one or two wells as individuals decided to invest. Wells were to be powered, where possible, with electric pumps connected to the slowly spreading rural electricity network. This involved another government agency, the Bihar State Electricity Board, which apart from problems of coordination, was faced with the linking up of a network of scattered pumpsets. Water was to be delivered through a system of concrete or brick channels.

The potential command of a 10-cm well on levelled land was expected to be 6 to 8 ha but the 5-hp pumpset could irrigate 12 ha of irrigated dwarf wheat. Fragmentation of larger holdings as well as the small size of holdings in comparison with the potential capacity of such a tubewell system prevented most farmers from profitably investing in tubewell irrigation or, for the reasons considered below, benefiting from the purchase of water. Mortgage requirements for the package costing initially Rs 8 000 also limited credit-financed investment to farmers with at least 3.2 ha.

My hypothesis is that the combination of the potential profitability of tubewell-irrigated farming, once high-yielding wheat had been introduced, and the embodiment of tubewell technology in a package that restricted the opportunities for profitable investment induced a process of local innovative activity. The "invention" of the bamboo tubewell was no chance occurrence or isolated act of inspiration but part of a process of induced technical and institutional innovation. This hypothesis can be substantiated in two ways: from interviews with farmers and contractors during the period in which they were actively engaged in experimentation to reduce tubewell investment costs, and by an investment appraisal of alternative choices of technique that confronted the potential investor with respect to the three major components of a tubewell system, the well, pumpset and delivery system.

Evidence from interviews and time series statistics on the sinking of different sizes and specifications of tubewell (Table 1) indicate that small-scale contractors and farmers began experiments to adapt tubewell technology to local conditions from 1965 onward. A few contractors and farmers with business contacts outside the region found that they could substantially reduce investment costs by importing their own materials, sinking shallower wells and using local contractors to install the wells. By privately installing wells, they also cut out the lengthy delays and other hidden costs of credit-financed investment.

The culmination

Through experience, contractors found that the very high water table throughout most of the region and the deep deposits of stone-free sandy alluvia made it possible to sink wells to only 30 to 36 m and still provide an assured water supply. In these conditions, expensive brass screens brought little advantage and did not necessarily lengthen the life of a well. Without fully realizing this, local cultivators began to install cheap iron screens be cause they preferred lower investment costs and a higher immediate return to a potentially more durable investment.

Local contractors also discovered that, using the simple "sludger" drilling method previously developed to sink narrow diameter wells to be powered by handpumps, they could sink 7.5- and 10-cm wells in the soft strata down to 45 m at lower cost than government rigs. Apart from the blind pipe and an auger, this technique uses only local materials.

Local cultivators found that it was possible to further reduce the cost per hectare of an irrigation system by sinking several wells, all of which could be powered by a single mobile diesel pumping set. In this way, again rejecting the official choice of technique (electric power), they could overcome both the indivisibilities in pumping set investment and adapt the technology to take account of fragmented holdings and uneven land. Due to the existence of a high water table throughout most of the region, in all but the driest summers, pumps could operate at field level and power units could be moved from well to well with comparative ease in contrast to regions of Uttar Pradesh and the Punjab where pumpsets are placed in excavated pits.

Farmers also rejected another official choice of technique in preferring to construct only kutcha earth channels rather than to install cement channels that represented an unprofitable investment where holdings were fragmented, terrain broken and few wells irrigated more than 2 or 3 ha.

The development of the bamboo tubewell was the culmination of these many attempts to reduce the cost of tubewell technology. A wealthy former Zamindar veteran of the independence movement and afterwards a Sarodaya leader carried out in collaboration with some other farmers more systematic experiments to reduce well costs. Modifications tried included coconut co* wrapped around steel and afterwards bamboo frames. Eventually one of these farmers, R.P. Choudhury, succeeded in sinking a well with bamboo casing instead of steel pipe, also using the coir and bamboo screen. As with so many successful technical developments, the tendency to credit one individual with the "invention" has obscured the process of economically motivated, and in this case philanthropic, experimentation that lay behind the innovation.

In assessing the impact of these innovations on employment and income distribution patterns in the Kosi region, one ought to take account of the consequence for landless labourers who, by 1971, comprised half of the population in this largely rural area, as well as for large and small farmers.

An oversimplified analysis

The techniques of assembly and sinking of bamboo tubewells as well as the complementary work on land levelling and channel construction largely involved unskilled labour and a minimum of capital equipment. My estimate is that in 1972-73, 300 000 man-days of additional employment were created by the fabrication and sinking of at least 14 000 bamboo wells, and 100 000 man-days through subsequent earthworks. In addition, the maintenance of a stock of 40 000 bamboo wells would generate 150 000 to 200 000 man-days of employment annually, according to whether one assumes an average life expectancy for wells of 4 or 3 years. However, this is considerably less than the additional employment generated by tubewell-irrigated farming which even in 1971-72 was estimated as at least 1.7 million man-days when there were less than 5 000 operational wells in the region. Approximately 30 percent of incremental net product from more intensive cultivation went to agricultural labour. The low cost of bamboo tubewells and the development of a market in pumpset services enabled many more farmers to introduce tubewell-irrigated farming profitably. It was the overall labour-using character of the package of innovations associated with tubewell-irrigated farming more than the labour-intensive nature of bamboo tubewell fabrication and sinking techniques that had the greatest impact on employment. However, any assumption that the primary beneficiaries of low-cost technologies will be small farmers appears to rest on an oversimplified analysis.

First, the development of a low-cost well brought at least as much benefit to the larger farmers with their fragmented holdings. Most of those involved in innovative activity were large landholders seeking to find ways of more profitably exploiting the potential of tubewell irrigation. Even their larger plots often included land at different elevations that could not be irrigated from a single well without prohibitively expensive investment in land-levelling and channel construction. Larger farmers first recognized the possibilities of spreading the service of a pumpset over several wells. Among a random sample of 54 tubewell investors surveyed in 1971, there was one farmer with 11 wells and several others had two, three and more bamboo wells. As Table 2 shows, the distribution of the first 1500 bamboo wells included few small farmers. It was the provision of subsidized credit for bamboo tubewells in 1972-73 and the development of the pumpset service market that enabled small farmers to sink tubewells in large numbers. As the lower cost wells could be profitably installed on smaller plots, this also left more spare capacity and the sale of water, mostly to small farmers, also became more widespread. However, dependence on the purchase of water or hire of pumpset services is another reason why the small farmers will be less able than the larger farmers who own their own equipment to exploit fully the potential of tubewell irrigation. The sharing or marketing of pumpset services introduces into the operation of small well systems the problems of organization and distribution that plague larger tubewell, low lift and surface systems; the unit of control is no longer the unit of crop production decision-making. Since the usefulness of irrigation water depends critically on its timing, it is reasonable to assume that owners will always satisfy their own water requirements first. Potential water buyers have to make their own requirements consistent with those of the seller. Also, they must expect to bear more of the costs of any breakdown of equipment or shortage of fuel in terms of reduced yield due to untimely supply of water. The expected value of services will be higher for owner-users than for buyers. This analysis is supported by evidence for 1971 showing that those who hired pumpset services irrigated less frequently, and applied less supplementary water in growing high-yielding varieties of wheat.

Experience elsewhere on the operation of cooperatives for pump hire and government-managed deep tubewells suggests that these alternatives to private sale of services are unlikely to overcome the problem of unequal access to scarce services. When time-specific water requirements of crops such as high-yielding wheat make water a constraining input, then the same more powerful members of the community will be able to ensure that they have first call on available services. There remains the problem of unequal access to other complementary inputs: fertilizer, better seed, pesticides, mechanical draught power for peak period operations. These are all part of the problem of the small farmer who faces multiple constraints in competing with the large and powerful farmers for economic resources. This is why the relaxation of a single investment constraint is not a sufficient condition for a social revolution.

The bamboo tubewell and associated innovations in the Kosi region are only one example of the adaptation of lift irrigation technology to highly specific local environmental conditions and farming systems. But most other examples reported from the Indian subcontinent conform to a similar pattern: lift irrigation was first introduced in some government programme, rarely preceded by research and development into what would provide the most cost-effective package. Innovation and adaptation were largely left to farmers and small local contractors more sensitive to the needs of their potential customers.

The optimal choice

These examples of adaptation should not be interpreted as offering solutions to general problems, for presumably the more successful the process of adaptation is to a specific set of conditions, the less likely it is that such technology will transfer to different environments. For example, most of the cost advantage of bamboo wells over other cheap structures is lost where it is not possible to lift water with a mobile pump at ground level. Bamboo wells are easiest to sink and operate most efficiently in the coarse sandy alluvia with high water tables that are characteristic of the Kosi region. Elsewhere, when the chances of finding water are less and there is no alternative to costly high-speed drilling to greater depth following careful presurvey of groundwater resources, then high investment cost and more durable structures may represent the optimal choice of technique. In Bangladesh where factor prices and availabilities probably favour even more labour-intensive irrigation techniques with the substitution of human labour for powered pumpsets, then hand-pumped all metal retractable tubewells removed before the floods are being used for irrigated boro rice cultivation.

An important lesson to be drawn from the case of the bamboo tubewell is that there is often an enormous potential for research and development to adapt technologies to highly specific sets of conditions. Farmers and the small-scale private sector will try to do this where there is opportunity for low-cost experimentation that does not require high-level engineering skills and complex engineering support facilities. Where these conditions are not satisfied, there are opportunities for research and development by the international and national research agencies in machine technologies with potentially very high rates of return.