WEED CONTROL Herbicide Residue Amber (triasulfuron) 0.013 or 0.016 lb/A (0.28 or 0.35 oz/A) may carryover in soil for more than three crop years. Amber should not be applied to fallow cropland with soil pH greater than 7.9. The rate of Amber breakdown increases as soil pH decreases. Proso millet can be planted 4 months after application. Rotational crop restrictions for Amber are found on page 64 of the 1996 North Dakota Weed Control Guide in the table, "Rotation Restrictions for Crops Grown in North Dakota". All other crops may be seeded only after the completion of a successful field bioassay. For additional information on Field Bioassay Instructions refer to paragraph E3.