Whether to use more cattle or farm machines has been a much-debated question in agriculture. However, this discussion has proceeded in the absence of any overall assessment of mechanical energy requirements, and overall land requirements for draft animals. Further, there are many combinations of animals and machines which would make sense under the great diversity of conditions in agricultural and the overall rural economy in the Third World.

Let us first consider the advantages and disadvantages of draft animals. This will illuminate what ways in which animals and machines can be used more effectively to provide the additional power needed for agriculture.

Draft animals have the following salient advantages which have led their use to be so widespread:

1. They reproduce themselves and do not require large capital outlays if an appropriate stock of animals is maintained.

2. They provide cow-dung as fuel (or return nutrients to the soil), milk, meat, and leather.

3. They are flexible in that they can be used for many different purposes such as ploughing, threshing, irrigation, and transportation.

4. They can be obtained in small unit sizes (in terms of power per unit), a big consideration for small farmers.

5. They are not dependent on external supplies of fuel, so that the element of risk in fuel cost is minimized.

6. They largely involve non-monetized energy sources, and use non-monetized labor which is available especially in the off-season.

7. They can provide peak power at several times the average power over short periods.

Despite these advantages, the number of draft animals is not large enough to fulfill energy needs for agriculture in South Asia. This is because the principal advantages of draft animals can accrue only to farmers already possessing cattle and adequate amount of cultivated land to provide fodder and off-season grazing land. Initial capital outlays for acquiring cattle are substantial, and their maintenance can involve considerable monetary costs if the farmer does not possess enough land to produce the required fodder. Thus, the monetary costs of draft animals can be considerable and often out of the reach of the small farmer. As we have seen, even in those cases where farmers do have cattle, their numbers frequently fall short of meeting the needs of present cropping intensity, much less increasing it.

One indicator of the difficulties of small farmers in acquiring sufficient draft power is the fact that in South Asia draft cattle population has been increasing far slower than rural population. In India, the growth of the cattle and buffalo population during the 1980s has been about 0.6% per year,. The figure for Bangladesh is .8% per year. In Nepal cattle population has actually declined by about 14% from 1980 to 1988. Among the countries discussed here, Pakistan is the only one to have seen a substantial and consistent increase in cattle and buffalo population of 2% per year during 1980-1988.¹ There is some uncertainty in these data for cattle population.

The poor overall efficiency of draft animals and the substantial land requirements for maintaining them are largely responsible for the shortage of draft power in land-scarce situations. Of course, these shortages affect those who have small parcels of land more severely. This raises the question of a role for farm machinery for small farmers and others who need to increase mechanical energy inputs to agriculture but are restrained by the expense of feed or by shortages of fodder or grazing land.

The efficiency of modern energy use in farm machines is typically an order of magnitude greater than farm animals, even under conditions in the rural Third World where electricity distribution losses tend to be high and where machines tend to be among the older and less efficient models that are available.

As we have discussed, the total intake by the draft animal system per draft animal in India is in the range 30 to 50 GJ per year per draft animal, and the output is in the range 0.5 to 1 GJ per animal per year. Thus, the total annual energy output of draft animals in India is 45 to 90 petajoules corresponding to inputs in the range 2,700 to 4,500 petajoules per year.

Modern energy use in Indian agriculture is 560 gigajoules. Assuming an average efficiency of 15% to 20% for modern energy, the inputs of modern energy provide useful energy of about 84 to 110 gigajoules. That is even though draft animal inputs are five to eight times greater, modern energy use in rural India provides a comparable or larger amount of useful energy to agriculture. This is largely due to the fact that animals eat all year and work only a small fraction of the time, while machines use no energy when they are not running. Table 11 summarizes these figures.

However, average efficiencies do not tell the whole story. The system of draft animals exists and is the mainstay of agriculture in South Asia. Thus, a crucial question is: what is the marginal efficiency of feed? In other words, given that feed is insufficient, how much could energy output be increased by increasing the quality and quantity of feed during the peak agricultural season?

Experimental work done at the Centre for Tropical Veterinary Medicine in Edinburgh, Scotland, indicates that the marginal efficiency of feed for an animal doing heavy work during the work day is about 18%.² (In this calculation, energy intakes during non-working hours and non-working days are ignored.) Thus, the output resulting from additional high quality feed to existing animals can be obtained at marginal efficiencies comparable to farm machines. This indicates that the expansion of traction energy output by increasing feed availability to existing animals should be a much higher priority than expansion of energy output from draft animals by increasing animal population. This approach also reduces the build-up of methane per unit of useful energy output.

This addresses to some extent the problem of the poor peasant who does have some draft animals. However, it still begs the question of where the additional feed is to come from, especially if it is to be high quality feed. It also leaves out the problems of those who have no animals, or where draft power is seriously inadequate for traction power, for irrigation, or for compressing work at peak time into fewer days to enable double cropping.

Let us first consider some aspects of farm machines before we address these issues. The difficulties with modern energy sources are well known. Farm machines require considerable monetary investment and usually come in much larger sizes than animals, though it is possible and often desirable to reduce the size of machinery. That is, while draft animal system can be acquired half horsepower at a time, the smallest machines are typically several horsepower or even several dozen horsepower. Further, the availability and price of oil or electricity is a source of considerable uncertainty. Finally, oil and electricity both involve considerable amounts of foreign exchange. It should be noted, however, that for specific applications, the price per horsepower of machines can be considerably lower than for draft animals.

Despite these disadvantages, modern energy sources have some powerful advantages: high efficiency, and very low land requirements. The scarcity of grazing land and fodder, the very substantial needs for additional power for increasing land and labor productivity as well as employment means that modern energy sources can be used to increase agricultural productivity, especially for poor peasants who do not now have adequate draft power, and for those who need additional power for increasing cropping intensity and land productivity per crop.

Farm machines can be used with the explicit purpose of getting over the chicken-and-egg problem of shortage of fodder and grazing land leading to inadequate draft power and low output. Increases in crop output on land of farmers who have no cattle or very few cattle, that is selectively on the lands of the poorest farmers, creates the prospect of providing crop residues to those who have larger numbers of farm animals. Thus, shortages of fodder and grazing land could be alleviated and the income of poor farmers can be increased simultaneously.

The following ways in which animals and farm machines can be used as supplements, complements and substitutes emerge from these considerations:

1. The use of farm machines on farms of farmers who do not have farm animals or who have the potential of producing crop residues in excess of the requirements of their own animals. This would alleviate shortages of grazing land and of fodder for farmers who have larger numbers of farm animals, providing a reinforcing increase of energy output for this group as well.

2. The cultivation of high quality feed for sale during the peak season so as to increase energy output of farm animals in areas where this is limited by shortages of adequate feed in the peak season.

3. The use of farm machines to substantially increase the total amount of draft power available in areas where such needs cannot be met by improvements in output per animals or modest increases in animal population.

4. The use of farm machines to reduce peak labor requirements to enable increases of cropping intensity.

A considerable amount of this has already been happening, of course, as output has increased substantially over the past few decades. But agricultural policy needs to be made explicitly in light of the needs for peak power and useful mechanical energy output. In land-scarce South Asia there is a need to devise strategies to increase draft power output without increasing substantially the numbers of draft animals.