DEVELOPMENT OF THE LIFTING UNIT OF A CASSAVA HARVESTER

Abstract

The cassava lifting unit was designed and fabricated at the Federal University of Technology, Akure using locally available materials. As part of the development of a tractor-mounted harvester for cassava (Manihot esculenta, Crantz). The cassava lifting unit is suitable for local conditions in the cassava growing areas of Nigeria. It saves labour, saves time and reduces drudgery during harvesting. The major components of the machine are; the lifting disc, chain and sprocket drive, speed reduction gear box, frame, cassava stalk deflector and hitching point. The machine is powered by the power-take-off (PTO) of the tractor at 540 rpm speed and transmitted via the reduction gear box of ratio 19:1 then to the driving mechanism (chain and sprocket) which drives the lifting discs to perform the third stage of harvesting cassava. The field test was conducted at the Federal University of Technology, Akure teaching and research farm with one variety of cassava (sweet cassava). The tests were conducted at 1m interval spacing to evaluate the effect of different levels of parameters on the performance of the implement. The parameters varied were forward speed, depth of cut and soil moisture content. The harvester was operated at forward speeds of 2.0 km/h, 4.0 km/h, and 6.0 km/h, depth of cut 30 cm, 32 cm, 34 cm and soil moisture content of 15 %, 17.5 % and 20.15 % (wet basis) using moisture meter. The parameters kept constant were, soil type, variety of cassava and lifting speed. The field capacity or harvesting rate which is the area harvested per unit time was also measured. The lifting efficiency is high at an optimum moisture content of 20 % wet basis. The optimum forward speed and depth of cut for efficient lifting of the cassava was 4 km/h and 34 cm at 60 % moisture content and soil penetration resistance was taken in the first day twice (morning and evening) at different depths. The final reading was taken three days after which rain had fallen. The lifting efficiency evaluated at optimum forward speed and soil moisture was 60%. Through the test of the machine, the results showed that the cassava harvester runs smoothly.