Abstract:
Carrot is one of the widely produced and consumed root vegetables in Ethiopia. Carrot
harvesting was practiced by traditional method using metal hoe, which is characterized by high
man-hour requirement, drudgery and considerable losses in terms of root damage and
inefficient exposure. Thus, it was important to consider a small horsepower tractor drawn
carrot digger for Ethiopian smallholder farmers was designed and fabricated by considering
soil, root and machine parameters and performance evaluation of the machine was carried out
in the experimental area at Bate Kebele, Haramaya Woreda on farmer’s field. The machine
mainly consists of main frame, shank, power transmission system, V-shaped digger blade,
eccentric pin and soil separator units. Some physical and mechanical properties of the carrot
roots and soils, relevant to the design of the digger were also studied. The experimental design
used was factorial randomized block design where speed (2.5, 3 and 3.5km/hr) was the main
factor; the rake angle (15o, 20o and 25o) was sub-factor with three replications as a block. The
effect of rake angles and forward speeds were evaluated in terms of draft, digging efficiency,
damage, soil separation efficiency, field capacity, field efficiency, wheel slip and fuel
consumption. The best optimum combination of rake angle and speed to be 20° and 3.5km/hr
respectively. At this optimum condition digging efficiency, damage percentage, field capacity,
field efficiency, soil separation efficiency and wheel slip were 91.87%, 3.29%, 84.93%,
0.25ha/h, 80.95%, 89.49%, 17.68% respectively. Fuel consumption to finish the one-hectare
land and maximum draft force was 17.56l and 6111.4N respectively
