Effects of Tillage Method and Incorporation on Trifluralin Carryover Injury1

Abstract

AbstractA Bolivia silt loam soil was spring plowed in 1969 and preplant treatments of trifluralin (a,a,a‐trifluoro‐2, 6‐dinitro‐N, N‐dipropyl‐P‐toluidine) were incorporated with a power rotary tiller operating 2.54 cm and 10.16 cm deep and with a disk‐harrow operating 7.62 cm and 15.24 cm deep and plante d to soybeans [Glycine max (L.) Merr.]. Soil samples were taken at three intervals following application at 0‐ to 5.08, 5.08‐ to 10.16; and 10.16‐ to 15.24‐cm layers of the soil profile. These soils were analyzed for trifluralin and were used for a plant bioassay using a sorghum‐sudan hybrid. The field plot area was divided into three sections with each section divided into a disked and a plowed area, and was planted to wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum [Sorghum bicolor (L.) Moench]. Depth of incorporation did not affect total amount of trifluralin remaining II months after application but did affect concentrations at different intervals in the soil profile. Trifluralin carryover injury to corn, grain sorghum, and wheat occurred on field plots.