Motorization and small vegetable farms in the Tunisian Sahel: performance and soil preparation costs

In this research work, we compare the small powers (two-wheeled tractor and small tractor) to the standard tractor in terms of hourly performance or field time, soil preparation costs and field yield. These machines have been used on three soil types with different textures (clayey-sandy, sandy-clayey and sandy) in the “Sahel”, the Tunisian central coast area, characterized by small-sized farms producing vegetable crops. Results show that for all operations, the best hourly performance is obtained with the small tractor. Indeed, this performance equalled on average 5.5, 4.1 and 2.8 hours/ha, respectively for ploughing, for the first and the second shallow ploughing. Regarding the field yield, the two-wheeled tractor and the small tractor were more powerful. They got respectively 70 and 62% in ploughing, 76 and 70% in the first shallow and 68 and 65% in the second shallow ploughing. In terms of soil preparation costs, the small powers were the best and particularly the small tractor. The latter led to an average cost for the three soil categories of 75.1 TD/ha, against 132.2 TD/ha for the two-wheeled tractor and 211.4 TD/ha for the standard tractor.