threshv.打谷；脱粒；反复地做threshing cylinder axis脱粒滚筒轴thresh-old illuminance阈照度threshing and separating脱粒与分离threshing prior to cutting割前摘脱threshing tool for one ear小型单穗脱粒设备Threshing and redrying line打叶复烤生产线threshod vegetation coverage临界植被盖度threshing and separating unit脱粒分离装置threshing-winnowing machine脱粒扬场机threshing of before-cutting割前脱粒