The design and development of a reversible animaldrawn plough and a ridger is presented . The plough was developed on the basis of laboratory experiments reported earlier to determine optimum parameters for a curved 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% 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 ΠΈ 5 , 1 ΠΈ 3 and 3 ΠΈ 3 Hz . Preliminary assessments were made to