Efficiency Considerations

We will first evaluate the efficiency of a prototypical system where draft power is provided by bullocks. We will first consider efficiency on the basis of the requirements of sustaining a single bullock.

We define efficiency as the ratio of the work done by the draft animal to the energy value of the feed. Marginal efficiency is defined as the additional work output for an additional unit of energy input. A higher figure of net efficiency is obtained if we include considerations relating to dung. Some of the energy intake which does not appear as work output can be recovered in the dung and reused as fertilizer or as a source of energy, it is reasonable to subtract the practically collectible portion of the dung from the energy intake when computing the efficiency of the animal in those instances where dung is actually collected and used in one of these ways.

A typical bullock in South Asia is capable of producing about 300 to 400 Watts of continuous power (about one-half horsepower).^1,2 It is capable of several times this effort for a short period. On an annual basis, the actual average power output is likely to be considerably below the capacity of the animal for continuous work, because animals work on light loads for a considerable portion of the time.

A thousand hours of work per year (6 hours per day for about 175 days)³ and 250 watts of average output, is about the maximum that such an animal will provide in energy output per year. Under these assumptions, the annual output of energy amounts to 250 kilowatt hours or 0.9 gigajoules. This is a practical upper limit for the annual energy output of an average bullock.

To get the upper limit of efficiency estimates, we take the input to be 20 gigajoules per animal per year, the lower limit of our estimates for energy intake (see Table 4 in chapter 2). About 25% of the input energy can be collected as dung and used as fuel, so that the net energy input is about 15 gigajoules.

For an output of 0.9 gigajoules, we get an estimate of the efficiency of draft animals of 6%. If we ignore dung recovery, then the efficiency would be 4.5%. This is about the upper limit of a range of efficiencies which one might calculate for draft animal use in agriculture.⁴

Under many circumstances, draft animals do not work as many as 1,000 hours per year. This might happen under circumstances where there might be mechanical farm equipment as a complement for animals or where the work on farms involves high peak energy outputs. The latter is the case for instance in wet rice cultivation. Animals may do lighter work for a large proportion of working time which means reduced total energy output. We have taken some of this into account by assuming an average output of 250 Watts, compared to a potential continuous output of 350 Watts. Finally, animals which do not have adequate feed would not provide the energy outputs which we have assumed above. Under these circumstances, annual efficiency would be lowered.

We also need to take into account the other animals which need to be maintained to reproduce the stock of draft animals. This consists of three components:

1. Calves must reach a minimum age and size before they can work effectively.

2. A certain number of cows must be maintained for the purpose of reproduction. (These cows provide milk as a by-product of considerable value. It should be noted however, that animals used for large-scale commercial milk production are usually not the ones also used for reproduction of farm animals, at least in India. In fact, in most of India, the main milch animal is the buffalo, while the main draft animal is the bullock.)

3. There are female calves in excess of those needed to maintain the reproductive system for draft animals. These calves can be used for milk or beef production, but they are generally not used for farm work.⁵

Rao has made estimates of the first of these three components:

An additional 5 gigajoule energy input per year increases the range of energy inputs required per year from 20 to 40 GJ to 25 to 45 GJ per year.

We have not come across any estimates of energy requirements for the other two items in our list which involve cows. We might ignore the third item in most circumstances as excess female calves which are not retained for reproduction are generally sold for meat. Thus, this part of the cattle population can reasonably be assumed to be a part of agricultural output for which there are inputs of fodder, grazing land, and labor, relatively independent of the draft animal system.

The second factor may involve considerable amounts of energy. However, in order to make a reasonable estimate, a breakdown of the purpose of female cattle population is required. Generally, the number of cows devoted to reproduction of male cattle would be several times smaller than the draft animal population.

We do not have estimates for this portion of energy inputs to draft animals systems. On an order of magnitude basis it will certainly be considerably lower than the inputs to the working animals. For lack of data, we might assume the net energy inputs for cows needed to maintain the bullock population as about equal to that needed by young non-working males - that is, about 5 gigajoules per year per working bullock.

This gives us a range of energy inputs per draft animal for the entire system as 30 to 50 gigajoules per year. The energy output is in the range of about 0.5 to 1 gigajoule per year. Thus the overall efficiency of the system would be on the order of 1% to 3%. Of course, this is a rough range of figures, given the considerable uncertainties in the data.

Power Requirements

Poor farmers often experience severe shortages of draft power at peak periods in the farming season. These may occur during certain land preparation activities, such as ploughing or puddling, or during harvesting. Shortages of draft power are also felt in case there are unmet irrigation needs in the context of available water supply. Finally, unavailability of mechanical energy may prevent increases in cropping intensity.

These shortages arise from two related basic causes. First, small farmers are too poor to purchase and install an adequate amount of farm power, whether this is in the form of draft animals or farm machinery. Second, their land holdings may be too small to allow economical use of even small equipment. The latter constraint applies more to mechanical equipment than to farm animals because farm animals come in small increments of power.

Table 6 shows the installed capacity of animal draft power per hectare in four countries in South Asia. The figure for average installed power on U.S. farms (excluding motor vehicles) is shown for reference.

Since Table 6 does not include farm machinery, it does not represent the averages for these countries, but rather the typical circumstances of the middle or upper middle peasant on non-mechanized farms.⁷ Available data indicate that tractors are used on the order of 10% of the cultivated land in India and Pakistan. We have adjusted the figures for installed power per hectare by attributing 90% of the cultivated area to draft-animal-powered farms.

The installed power per hectare is low on the average. When we take income differences and other local conditions into account, we may infer that in a great many situations, shortages of draft power for small farmers are likely to be considerable. This, in turn, is likely to have a considerably deleterious effect on land and labor productivity.

Table 6 Draft Animal Power in South Asian Agriculture
Country	Cultivated area, 106 ha.	Draft animal power 106kW	Specific power draft animals kW/ha.4
Bangladesh	9.2	3.0	0.36
India	169	33.9	0.22
Nepal	2.3	1.2	0.57
Pakistan	20.8	3.8	0.2
USA (machines)	190	266	1.4
Notes: 1. The data on the number of draft animals are from the notes to Table 4. We assume that each animal has an "installed" capacity of one-half horsepower or about 0.37 kW. The actual average power output over long periods of work may be somewhat lower, perhaps on the order of 0.25 kW. One indication of the degree of uncertainty in the above estimates is provided by citing a different estimate by Singh et al. They assume the total number of draft animals in India in 1981 to be 63.3 million with a total power of 18.6 million kilowatts (Singh et al. Table 13). Since their estimates for the number of draft animals as well as the power per draft animal are lower than the figure we have used, the result for total power is much lower. However, Singh et al. provide no source for their figures, nor do they discuss the method by which they arrive at their estimate. Hence we have not used this data in this paper. 2. The data for farm machinery in the U.S. are provided for comparison. These data also reflect installed horsepower. The utilization the installed capacity in terms of maximum power needed over short periods to installed horsepower will be less unfavorable to draft animals because the ratio of peak output to average output is larger for draft animals relative to farm machines. Source of data for U.S. farm machines: U.S. Statistical Abstract, 1989; Table 333. 3. Land use data from FAO Production Yearbook, 1988.

Consider the following example, based on personal observation.⁸ In much of the Deccan plateau in southern India, the rains are highly variable, the soils are clayey and, after a long and searing dry season, difficult to plough. In parts of Maharashtra, proper ploughing which would turn up the portions of the soil still containing some moisture after the dry season requires about 3 horsepower, which is about 3 pairs of bullocks. Most farmers do not own three pairs of bullocks, not only because of a shortage of capital, but also because of a shortage of feed to sustain so many draft animals. The average installed horsepower of bullocks in India is only one-third of a horsepower per hectare and many poor peasants would have considerably less than this. Agricultural requirements in much of the Deccan are also increased by the need for irrigation to allow reliable yields and multiple cropping.

The contrast between well-watered and ploughed fields and unirrigated, under-ploughed fields is dramatic. The former can produce two or even three crops, with yields of two or three tons per hectare per crop. The latter produce a few hundred kilograms of coarse grain per year, and as little as 100 to 200 kilograms per hectare in poor years.

To begin with, let us calculate the energy inputs and outputs of the irrigated farm with no shortages of draft power and compare it to the unirrigated farm with inadequate power. First, the irrigated farm:

We assume that the level of power availability is 1 horsepower per hectare, and that a total of three pairs of bullocks are available, which is the minimum requirement for adequate tilling. This means that the bullocks would work three hectares of land, assuming 1 horsepower per pair of bullocks. We will use the systemic energy inputs in the range of 30 to 50 GJ per bullock per year, which includes energy inputs for non-working animals associated with a draft animal system.

The energy input per pair of bullocks would be about 60 GJ to 100 GJ per year. Approximately 50% of the energy input exits the animal as dung. We also assume that 50% of the dung is collected so that about 25% of the energy input is recovered as dung for domestic energy use. Thus, the net energy input to the animals is 45 to 75 GJ per year per hectare.

About half the energy input is used in field operations, a quarter in crop processing (i.e. 75% in agricultural production) and the rest in transportation.⁹ Thus the draft animal input to agricultural production is about 34 to 56 GJ per year. For two crops per year and an irrigation requirement of 10 GJ per hectare per crop, a crop yield of 2,500 kg/hectare and a crop residue to crop ratio of 2,¹⁰ we get the following energy balance for an irrigated farm work by draft animals and diesel irrigation:

Table 7 Annual Energy Input for a Two-Crop Irrigated System, GJ/ha/year
1. Draft animals	34 to 56
2. Diesel irrigation	20
3. Fertilizer input: 200 kg urea/ha/year:	30
Total energy input	84 to 106
Energy outputs	GJ/ha./year
1. Food: 5 tons/ha/year @ 14 GJ/ ton	70
2. Crop residues: 10 tons/ha/year @ 13 GJ/ton	130
Total energy output	200

The energy inputs of about 100 GJ per year per hectare in this scheme produce an energy output of 200 GJ per hectare per year. The net gain is about 100 GJ and the ratio of output energy to input energy is about 2.

Next consider a rain-dependent farm producing a small grain like jowar. We assume that an average amount of draft power for India on farms without mechanical power is available on this farm. This amounts to about 0.3 horsepower per hectare, or one horsepower corresponding to one pair of bullocks for three hectares. There is only one crop per year on such a farm, typically, with an output on the order of 500 kilograms per hectare.

Table 8 shows the inputs and outputs for such a farm:

The upper limit of the ratio of output to input is about two, whereas the lower limit of the ratio is only 1.2. Moreover, the total production per unit of land in a land-scarce situation is clearly of paramount importance, and on this score also the rain-fed system is not adequate. Indeed, one of the most important advantages of the first system is the increased production per unit of land. The ratio of annual energy output of the two-crop irrigated farm to the unirrigated one-crop farm is almost nine to one.

In poor years, crop production might fall to 200 kilograms per hectare or less, and the highest energy output to input ration falls below 1. It is easy to see that when outputs are so low, the system is catastrophic for both humans and animals.

While this is an extreme example of the effects of the shortage of draft power in South Asian agriculture, similar figures would apply to considerable areas, since the Deccan itself is a large portion of South Asia, and many other areas are similarly semi-arid.

There are two principal differences between the farms in the above examples. The first is the use of irrigation and fertilizer inputs; the second is the availability of sufficient draft power. These two are not necessarily connected, though the completion of adequate ploughing and post-harvest operations in a timely fashion requires the availability of sufficient power and sufficient energy at critical times. Moreover, the availability of adequate power need not be in the form of machines in the specific instance. However, we will see that land constraints place a limit on the increases in draft power via animals that can practically be made available, especially in view of the competition for land for other purposes such as the production of food and fuel.

A similar problem confronts many small farmers in rain-fed rice culture. Rice culture is generally wet paddy cultivation, in which draft animals predominate. The draft power requirements in wet paddy cultivation are high in that the effort required to plough and puddle wet, muddy fields is considerable.

Shortages of draft animals at critical times are common. Poor farmers who do not own enough or even any draft animals must not only pay to rent them, they often borrow the money needed for this at high interest rates from moneylenders. They are also often forced to wait till the farmers who do own the cattle and rent them out have completed their own farm operations. One example of the relative prices of draft animals and labor in a rice-growing area on India's west coast is as follows: The price of a day's labor in the peak season was about $0.70. The rental for a pair of bullocks with a plough for a day was $2, excluding labor.¹¹ Of course, people cannot be substituted for draft cattle in puddling rice fields. They are complementary inputs, whose relative prices are nonetheless instructive.

It is not necessary to increase the amount of power available to farmers to accommodate the needs of tilling and irrigation at once. Pingali, Bigot and Binswanger have pointed out that in land-scarce situations biological technology changes generally precede mechanical technology changes and the reverse is true of land-abundant areas:

As a specific example, Goldemberg et al. have pointed out that considerable improvements in traditional rain-fed rice culture are possible without the addition of farm machinery, but with additional chemical, human labor and animal labor inputs. Increasing indirect energy inputs for fertilizers and pesticides from 331 MJ per hectare to 4,570 MJ per hectare, human labor from 725 hours per hectare to 983 hours per hectare, and animal labor from 342 hours per hectare to 440 hours per hectare is postulated to increase paddy yield from 1,860 to 3,500 kilograms per hectare.¹³

This means that by increasing energy inputs by about 8 GJ per hectare (about 4 GJ for indirect energy and 4 GJ for draft animals), the output (including crop residues) could be increased by about 66 GJ, a ratio of output to input of about 8.¹⁴

Poor peasants confront considerable obstacles to increasing mechanical power availability on three counts:

1. They do not have adequate access to capital to increase chemical inputs.

2. They do not have adequate draft power to increase animal labor inputs without additional capital.

3. The problem of shortages of draft power at crucial times is often accompanied by shortages of human labor at peak periods.

Operations like transplantation or harvesting and threshing need to be done within short periods. Small farmers who cannot afford to hire labor, and who are obliged to rent cattle with money borrowed at huge interest rates, also often suffer crucial labor shortages.

Borrowed grain or money is also often needed in order to be able to eat at all during the rainy season. Due to the high interest rates, farmers borrow as little as they can, minimize food intake, and thus are not able to work at their best. They also often plant early maturing varieties of crops in order to minimize borrowing even though such varieties usually have much lower yields. Finally, the rainy season is also a time of the peak incidence of water borne diseases, further cutting into much needed working time.

Fulfilling peak labor requirements from within the family under these very difficult circumstances provides an impetus to poor families to have large numbers of children. Of course, this same impetus also results in considerable surplus labor at other times of the year.

Given unmet peak labor needs, the alleviation of these problems is connected with the enormous amounts of time which women must spend on gathering fuelwood and other traditional fuels, as well as water carrying food processing, including cooking and other household activities. As with alleviation of peak power shortages, reducing the time and drudgery that accompanies the gathering and preparation of traditional fuels could, in many circumstances, lead to increased availability of labor for agriculture and increased productivity. These shortages occur despite efforts by the poor to stockpile fuel for the agricultural season, and the greater availability of water during the peak season. Thus, in many circumstances, the problems of creating local fuel supply through woodlots, of adequate draft power and of adequate labor are closely connected. (See Chapter 4.)

The magnitude of mechanical power requirements for productive agriculture is a critical factor in improving both land and labor productivity in South Asian agriculture. This is especially so for two somewhat different situations. First, shortages of draft power affect a large number of small farmers who cannot afford adequate draft power either in the form of draft animals or farm machinery. They are forced to rent draft animals which puts them at a serious disadvantage. It increases their cash requirements, and all too often the money they must borrow from moneylenders at exorbitant interest rates. It also causes delays in critical operations, since those who own draft animals give priority to their own operations before renting out to others.

A critical need of small farmers, therefore, is to improve output within the framework of the present cropping intensity. Second, there is the larger category of farmers, which includes small farmers, who need additional draft power to improve the technology as well as cropping intensity. This would apply to irrigation, to relieving peak labor shortages, and to accelerating certain farm operations such as harvesting and threshing to permit double cropping.