Farm Power

 The availability of power is a pre-requisite for any agricultural activity whether the source is human, animal or motorized. In developed country agriculture, the general availability of virtually unlimited amounts of farm power in its different forms is almost
taken for granted and comes almost exclusively from internal combustion engines or electric motors. The human is just the “brain” and control of the system. However, in most developing
countries, the human is also a major source of farm power. Just how significant is this and to what extent is human power used? How will this change in the future and can the required farm surpluses required to feed burgeoning urban populations be produced from an agricultural situation in those countries which rely to a large extent on human labour?

In developing countries there is a great variation in the proportional use of the three primary sources of farm power. In some countries there is a dynamic situation in which human and animal power is being replaced by mechanical power, but in others, farmers are having to give up mechanical and animal power and revert back to human power. In some others which are tragically hit by HIV/AIDS and other diseases, even the human power base is shrinking.

In order to examine the contribution of different power sources to agricultural production, two approaches were considered. The first was to base the discussion of the relative contributions of the different power sources to the total power input to agriculture, and the second was to take an area-based approach, focusing on the proportion of the total harvested area cultivated either humans, draught animals or tractors at a country level.

The first method starts with estimating the number of people, draught animals and tractors working in agriculture; converting each of the three power sources into a kW equivalent;
aggregating the total power input to agriculture; and then expressing the contribution of each power source as a percentage of the total. There are, however, four principal concerns with this approach; (a) the lack of availability and reliability of the base data,(b) the conversion into kW equivalents which relies on estimates of the power equivalents of human beings, draught animals and engine powered machines; (c) the expression of the data as a percentage of total power equivalents (due to the fact that the power produced by humans is so insignificant when compared to tractors); and finally (d) the difficulties in projecting over time particularly the substitution between power sources which occur over time.

As a result of these problems in using a kW equivalent and after a great deal of discussion, an area-based approach was adopted, initially focusing on the proportion of the total
harvested area cultivated by either humans, draught animals or tractors at a country level and then aggregated at both sub-regional and regional levels. There are two premises
under-pinning this methodology: (a) the power source used for primary tillage because land preparation represents one of, if not, the most significant use of power and it is usually
one of the first tasks to benefit from additional power inputs and, (b) the area cultivated by each power source as a percentage of the total harvested area.

On the basis of information we have collected as well as expert opinion, we have attempted to characterize different countries into different groupings according to their use of farm
power. We have also examined whether there are any similarities in economic and social indicators between countries with a similar mix of types of farm power. And, finally, using
these indicators and data we predict how the farm power situation will change from country to country and from region to region over the next two to three decades. As a basis for the
work countries were categorized into six farm power typologies:

Humans are the predominant source of power for land cultivation, with modest contributions from draught animals and tractors; Significant use is made of draught animals, although humans are still the most important power; Draught animals are the principal power source; Significant use is made of motorised power; Tractors are the dominant power source; Land cultivation is fully motorised.

Global, Regional and Country Overviews

All three sources of power (human, draught animal power (DAP), tractor) are widely used and widely dispersed, however, the use of the different sources and the extent to which they contribute to agricultural production varies from region to region, within a region and even within a country.

n Sub-Saharan Africa, in overall terms, humans are the principal power source, cultivating two thirds of the area under cultivation but there are regional differences with manual power being dominant in the Central region, draught animals being used to a greater extent in Western and Eastern Africa and in Southern Africa there is an increasing use of tractors

In Asia, one third of the land is prepared by draught animals whilst tractors are a significant source of farm power in much of Central and South America and the Caribbean. The use of tractors is also well established in the Near East and in North Africa.