Optimization of animal drawn tillage implement systems: Part 2, Development of a reversible plough and a ridger

The design and development of a reversible animal-drawn plough and a ridger is presented. The plough was developed on the basis of laboratory experiments reported earlier to determine optimum parameters for acurved implement. The basic design principles of conventional mouldboard ploughs and an ard were taken into consideration. A safety mechanism was developed which was a shear bolt. Apart from the share point, all components of the plough were made from wood, and the total mass was about 10 kg. The orientational parameters of the developed implement such as the tail angle, rake angle and the side-rake angle can be varied to suit the required soil operations and the pulling capability of the draught animals. The developed plough can also be used as a ridger by mounting an extra wing on the plough. Comparative field experiments were conducted in cooperation with the International Livestock Research Institute. ILRI, using the developed and traditional ard-type plough in Ethiopia. Tests were carried out in fields under various soil conditions using oxen and cows. The results showed that the draught required by the developed plough was about 30 percent less than the draught of the traditional Ethiopian ard. A frequency analysis was made to determine the dominant frequencies of the reversible plough under working conditions. The identified frequencies were 0.5, 1.3 and 3.3 Hz. Preliminary assessments were made to compare the performances of a pair of cows with a pair of oxen in relation to speed and forces when pulling the developed plough. A pair of cows moved faster (an average of 0.84 m/s) than the pair of oxen (an average of 0.63 m/s) and exerted proportionally greater pulling forces when operating in the same field. The difference in speed is explained by the greater body weight of the cows and the correspondingly greater pull that could be exerted

Gender Differentiation in the Analysis of Alternative Farm Mechanization Choices on Small Farms in Kenya

This study has been prepared within the UNU-WIDER project on Gender and Food Security, directed b

Conservation agriculture in Sub-Saharan Africa

Specific practices of conservation agriculture (CA) in sub-Saharan Africa are diverse and vary according to local farming conditions. However, despite more than two decades of investment in its development and dissemination, adoption of CA is low. Crop responses to CA are highly variable, and not always positive, which is an important hindrance for adoption, especially for resource-poor farmers who need immediate returns with their investments in CA in order to be able to feed their families. In contrast with commercial farms such as in Brazil, reduced costs with CA on smallholder farms in sub-Saharan Africa are not always observed. Another major challenge with the practice of CA is the use of crop residues for mulching since crop residues are a major source of feed for livestock, especially in semiarid regions, where biomass production is limited and livestock plays a crucial role in farming systems. Studies indicate that the three principles of CA, including mulching, are needed to increase crop yields compared with conventional tillage (CT)-based practices. Among the three principles of CA, mulching is certainly the one that is least observed in past and current cropping practices in Africa. CA has a potential to improve the soil water balance and increase soil fertility, and it is undoubtedly a cropping practice that can result in substantial benefits for certain farmers in Africa. The question is when and how it is the best approach for smallholder farmers in sub-Saharan Africa. In general, CA is more likely to be attractive for farmers with a strategy of intensification than for farmers who struggle to produce food for their family. The latter too often face multiple constraints that limit the possibilities to engage in technological innovations. Some farmers may not be interested in new technologies because they earn their income from off-farm activities. Good markets of input supply and sale of extra produce are a prerequisite condition for adoption of CA as they are for any other new agricultural technology that aims at intensification. In sub-Saharan Africa, there is certainly a need to better target CA to potential end users and adapt the CA practices to their local circumstances and specific farming contexts. (Résumé d'auteur