EFFECT OF HAMMER MILL AND ROLLER MILL VARIABLES ON CHEAT (BROMUS SECALINUS L.) SEED GERMINATION

Abstract

An alternative method for weed control is to devitalize cheat seed after secondary cleaning using mechanicaldevices such as a hammer mill and a roller mill that would be mounted on the combine. The effect of hammer mill shaft speed,screen size, feed rate, and hammer configuration; and roller mill roll gap and roll speed differential on cheat seed germinationwere investigated. Germination decreased as hammer mill shaft speed or number of hammers increased, and screen openingsize decreased. The hammer mill setting of 3,600 rpm with the 3.2-mm (8/64-in.) screen, 24 hammers, and feed rate of 50 g/s(0.11 lb/s) resulted in 3% cheat seed germination compared to 99% for control and hand-harvested cheat samples.Germination decreased with decreasing roll gap and with increasing roll speed differential ratio. The combination of thehighest roll speed ratio investigated (1:1.27) and the narrowest roll gap 0.1 mm (0.004 in.) reduced the germination 95%.