Even in countries where farming is beginning to be mechanized, power tillers and tractors are still restricted to tillage and a few other operations. This paper discusses the history of mechanization, the major reasons for the wide diversity observed, the options for developing countries in extending mechanization, and the role of government policy in influencing the choice of technology.
For example, in an extensively farmed area of Africa where hoe cultivation is used yields may be low, while in an intensively farmed tractorized region of India yields may be much higher. The yield differences may be caused in part by differences in other inputs, such as fertilizers or seeds. They could also be caused by better tillage in India-but this does not mean that good tillage is achieved only by tractors and cannot be achieved by hand. Examples from Java show that cultivation by hand can be as thorough as by ox or tractor.