This study has been conducted to investigate the feasibility of using the general
combine harvester in harvesting and threshing the sunflower crop. A comparative
study between the traditional method and combine harvester in threshing sunflower
crop was carried out through evaluation of several parameters concerning the
performance of combine harvester such as the drum (cylinder) speed (400, 500 and
600 rpm), forward speed (2.8, 3.5 and 4.2 km/h), length of feeding material (60, 120
and 170 ern), concave clearance (1.5 , 2 , 2.2 cm) , moisture content of crop (12, 16
and 23.5 %) The obtained results indicated that the optimum forward speed for harvesting
sunflower plant was 3.5 km/h. It gave the least total losses and the maximum level of
cleaning efficiency. Moisture content of 16 % (w.b) gave the lowest level of total
losses and seed damage and achieved the highest level of cleaning and threshing
efficiencies. While the optimum cylinder speed and concave clearance were 500 rpm
and 2.2 ern, respectively. The study also indicated that increased length of stalks
decreased total losses.