From planting to emergence, the range is over 30 days (the potato 18-25 days). During this period must be destroyed weeds and crust can form especially on heavy land and wet weather. The best results are obtained when the works are done as soon as weeds appear. The first work is performed at 10-14 days after planting. When planting was done on rising land, harrow ground working-net, the aggregate of three fields, the working width of 8.4 m and a forward speed of 5.7 km/h, harrows destroy the weeds and crust rising land ridge, and the interval between rising land. After 1-4 days working again, this time with thinning type cultivator equipped with tracks. To destroy weeds and crust in the area of rising land and by restoring them, cover and choke the weeds that tend to rise. Successive work-net harrow and cultivator parts such rarity, recovery Billon, repeats again (when they planted tuber sprouting) or 2 times to other cultures, after intervals of 8-12 days.
