RESIDUAL EFFECTS OF CGA-131036 AND CHLORSULFURON ON SPRING-SOWN ROTATIONAL CROPS

Response of flax, canola, field pea, sunflower, field corn, lentils, and common buckwheat to soil residues of CGA-131036 and chlorosulfuron applied at 22 g ai ha-1 was determined on two soil types at Morden, Manitoba. On a fine sandy loam with a pH of 7.4 and 4.5% organic matter, the length of time required before crops showed no phytotoxicity from CGA-131036 residues was: sunflower 4 yr; canola and common buckwheat 3 yr; flax 2 yr; field pea and field corn 1 yr. On a clay loam with a pH of 6.5 and 5.3% organic matter, the corresponding duration was: lentil, canola, and sunflower 3 yr; flax and field pea 1 yr. Chlorsulfuron residues persisted somewhat longer than CGA-131036 residues on the sandy loam but not on the clay loam.