Motorization has many advantages. The characteristics of an agricultural system will determine what are the main advantages that would persuade a farmer to use motorized inputs on his farm.

The most obvious benefit is the work potential of tractors versus hand labour and animal traction. This is most advantageous in communities where labour is scarce or expensive. The labour requirements for preparing one hectare of land for planting using draught animal power are only 12% of that required when using hand labour. When using a tractor with a plough, this falls to less than 1%, increasing labour productivity tremendously. As labour is a constraint in many farming communities, the use of animal traction and tractors brings the opportunity to expand the acreage. The holdings of cotton farmers using animal traction in Burkina Faso, Mali and Togo are 1.3 to 3.6 times bigger than the holdings of those relying solely on hand labour (Caumont, 1995). Motorization is likely to have an even greater potential for area expansion as long as land is available. Labour productivity will increase considerably. A farmer owning a tractor would normally be able to increase his income through increased production and by doing contract work for other farmers.

The author’s work on the spontaneous tractorization in rural communities in The Gambia supports the idea that farmers view saved labour and reduced drudgery as motorization’s main advantages. (Van der Meijden, 1994) A village chief voiced a widely held opinion, confirming that "owning a tractor makes farming easier and since there are tractors more work is done and more is grown than one person could ever do. People work more. That is good, we have higher production now." The tractor owner can often generate considerable income from doing contract work, such as tillage and transport for others. Although farmers in the village are aware of the increased risk of erosion that tractor use has caused, they are still very much in favour of tractorization. So, despite the fact that tractorization in this particular village is a spontaneous process, it is no surprise that it seems to continue without any external support or promotion. This indicates the likelihood that further tractorization and an increase in the degree of mechanization will take place, as a spontaneous process, where and whenever farmers have enough purchasing power to buy tractors and governments do not limit mechanization through import duties or other measures.

Labour shortages, most crucial during the period of land preparation at the beginning of the rainy season, (FAO, 1995a) result in untimely operations and limits both area expansion and total food production. This is especially true in cases where the cropping season is short. This explains why farmers often mechanise only land preparation, as it is the operation in the cropping cycle that has the highest labour demand; they rarely invest in other machinery since hand labour for those operations is still less costly and usually abundant. This ‘incomplete’ mechanization pattern is seen in the Gambia as much as it is elsewhere in West Africa. Some Gambian farmers have invested in two tractors for primary tillage only, rather than using one tractor with an extended implement package to include planting and weeding. (Van der Meijden, 1994) One farmer explained, "I have never had the ‘complete’ package. The reason I have two tractors instead of for instance one tractor and a sowing machine and a weeder is the demand for labour in the first two or three weeks of the rainy season. You have to do the ploughing and the sowing as quickly as possible. With one tractor I would be able to do only half of what I do now."

Questionnaire results confirm that the work potential/increased productivity aspect is the main advantage of motorized tillage. Two thirds of the respondents mentioned this aspect. Closely related to it is the extension of the area cultivated, which was mentioned by half of the respondents. An increase in yield per hectare was not mentioned, though it might be linked to increased productivity. One fourth of the respondents found reduced drudgery to be important. Other aspects that were mentioned are: good work, better tillage, increased living standard, increased income, increased export, urbanisation of rural areas and timeliness in rain dependent agriculture. A remarkable response came from The Gambia: less soil erosion potential. The suppression of weed growth, considered a major advantage of motorizing tillage, was not mentioned as an advantage.

Whether the intensification of tillage resulting from motorization has a positive effect on yields is very much dependent on the cropping system that is used, the agro-ecological zone concerned, etc. Assuming that motorization of tillage operations increases the soil volume disturbed by it, it is important to note that there is a positive and significant linear regression between the crop yield of maize and the total volume of soil disturbed by primary and secondary tillage in West African semi-arid conditions (Dunham, 1988, in Van der Meijden, 1994). However, the question is, how very sustainable this yield increase can be for soils that often have low natural fertilities and to what extend a short term increase in production will be undone by the long term degrading and destabilizing effect of intensive tillage. Farmers themselves mostly state that the use of tractors increases crop yields (Van der Meijden, 1994).