Physical parameters of some varieties of yam tubers relevant in the design of mechanical yam harvester

Abstract

Yam harvesting had been identified as one of the crucial and labour-intensive operations in producing the root crop. It involves standing, bending, squatting, and even sitting on the ground sometimes, depending on the size of ridges and depth of penetration of harvested tubers. During the period of harvesting farmers still use simple tools such as hoes, cutlasses and other simple farm tools. An efficient yam harvester is therefore not only necessary but also important to regenerate the production of yam to meet up with ever-increasing demand for the yam exportation. Thus, the knowledge of the physical properties of yams becomes imperative in the design of suitable and appropriate yam harvesters. The properties investigated were length, diameter and weight of different yam species and the height of ridges, space between the ridges and space between the rows. The results revealed that the range of mean values of: (17.34 – 48.66 cm), (7.53 – 14.23 cm) and (9.7 – 27.6 N) for the length, diameter and weight of yam species, respectively, will be useful in the design of space between the blades and adjustment of blades while that of the length of the yam tuber will be useful in the design of depth of penetration and adjustment of the digging device. While the range of mean values of 30.0 – 85.1 cm, 108.9 – 216.0 cm and 106.0 – 195.6 cm for the height of ridges, space between ridges and space between the rows, respectively, this will be useful in the design of spacing between each set of the blade to accommodate two ridges at once.