DESIGN, DEVELOPMENT AND PERFORMANCE EVALUATION OF TRACTOR DRAWN CARROT DIGGER

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