Alternate use of mechanical and chemical, methods of weed control in coffee crop

The use of several methods of weed control (disc-harrow, rotary cultivator, off-set rotary shredder and herbicide) was studied and compared with hand cultivation. The treatments were made alternatively, trying to prevent the inconveniences observed when certain machines were sistematically used. After five years of observations, no significant statistical difference was noticed among several combinations: a) off-set rotary shredder versus herbicide; b) off-set rotary shredder versus rotary cultivator; c) off-set rotary shredder versus disc harrow; d) off-set rotary shredder (in the rain season) versus herbicide (in the dry season).