Hosein Mosalanejad
Hosein Mobli
Afsaneh Poursoltan

Harvesting practices of potato is one of the most difficult, troublesome and sensitive stages. Potatoes enter the machine with huge amounts of clod and stones: In the meantime separation of potato some stone and clod, which are the same size as of that the potatoes, shall be confide red a major problem. Many methods of study by investigators are based on physical properties of potato, stone and clod. In the present research with regards to the farm conditions and economic situation of the Iranian farmers, the beveled conveyor method is recommended. In this method, primarily a schematic design of the separating section of the stones and clod and the crop was produced and important parameters such as the surface angle, conveyor-belt motion speed and type of the conveyor, which play a key role in the separation stage, were studied. The test was carried out on the factorial basis and complete random block, using ۳ angles factors in ۵ levels (۵,۱۰,۱۵.۱۷.۵ and ۲۰ degrees) and the speed on ۵ levels (۱۰۰,۲۰۰,۳۰۰,۴۰۰ and ۶۰۰ RPM) and the belt type with ۲ surfaces (soft and rough) repeated ۵ times. The  SPSS software was used to analyze data. The result revealed that the ideal combination of the angle, speed and belt type for acquiring the highest separation rate and the least amount of mix clod, stones of the separated potatoes are the order, and the crop would be the angle ۱۵ degrees, the speed of ۳۰۰ RPM, with the use of soft belt, and the angle of ۱۷.۵ degrees and the speed of ۲۰۰ RPM is recommended for a rough belt.