In countries that agricultural fields are small, most farmers sow pea seed by scattering them by hand, which causes to decrease the yield. Thus, the objective of this study was to investigate the performance of a cylinder-type vacuum precision seeder for sowing pea seed in small fields. The effects of vacuum pressure, speed of grease belt and diameter of seed hole were evaluated by examining the mean seed spacing, quality feed index, coefficient of seed distribution uniformity , and miss and multiple indices. The main variables were vacuum pressure (40, 60 and 80 mbar), grease belt speed (2.5, 5 and 7 km/h) and seed hole diameter (3, 4 and 5 mm). The results indicated that the maximum performance of the metering device was founded at the vacuum pressure, grease belt speed and seed hole diameter of 60 mbar, 2.5 km/h and 4 mm, respectively. The miss index, multiple index, quality feed index, seed distribution uniformity coefficient and actual mean seed spacing were obtained as 10%, 5.54%, 84.46%, 79.87% and 11.94 cm, respectively. In the treatment of 3-40-7 (hole diameter (mm), vacuum pressure (mbar), and belt speed (km/h), respectively), higher miss index caused higher mean seed spacing; this is while in the treatment of 5-80-2.5, higher multiple index caused lower mean seed spacing.
