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Pendimethalin dissipation and the influence of preemergence herbicides on Kentucky bluegrass shoot and root growth
Abstract
Pendimethalin dissipation and the effects of preemergence herbicides on Kentucky bluegrass were studied under field, greenhouse, and rhizotron conditions. Field studies were conducted on a Sharpsburg silty clay loam and an 85/15 (v/v) sand/Sharpsburg soil mixture was used for controlled-environment and rhizotron studies. Herbicide treatments included bensulide at 8.5 kg/ha, DCPA at 11.9 kg/ha, pendimethalin at 1.7 kg/ha, oxadiazon at 3.4 kg/ha, and prodiamine at 0.56 kg/ha. Leachate was collected weekly from rhizotron root cells to monitor pendimethalin movement. Plant tissue, thatch, and soil were sampled at 0, 10, 21, 42, 84 and 168 days after treatment (DAT). The soil was sampled at 0-2.5 cm, 2.5-5 cm and 5-10 cm depths in the field and rhizotron cells, with additional sampling at 30 cm, 60 cm, and 120 cm depths in the rhizotron. Pendimethalin concentration was highest in plant tissue and thatch and accounted for approximately 95% of pendimethalin residues detected at all sampling dates. Pendimethalin concentration decreased most between 0-3 weeks after treatment (WAT), and between 3-6 WAT. Trace amounts ($<$0.001 mg/kg) of pendimethalin were detected in rhizotron leachate samples collected at 7-14 days after heavy rainfall. These residues were primarily associated with soil colloids filtered from leachate, indicating gravitational displacement of particulate matter. Turfgrass quality, plant height, clipping yield, verdure, verdure regrowth, rhizome number and length, and root number, length and weight were measured. Oxadiazon reduced turfgrass quality. Oxadiazon and prodiamine reduced clipping yields when compared with the control. Oxadiazon reduced plant heights in greenhouse, but not in field and rhizotron studies. Root lengths and weights were variable for all treatments. Prodiamine reduced root length by 30%. Roots of pendimethalin and DCPA-treated turfgrass were 27% shorter than those of oxadiazon-treated or untreated turfgrass in the 1987 rhizotron study.
Subject Area
Agronomy
Recommended Citation
Stahnke, Gwen Kristine, "Pendimethalin dissipation and the influence of preemergence herbicides on Kentucky bluegrass shoot and root growth" (1989). ETD collection for University of Nebraska-Lincoln. AAI9013629.
https://digitalcommons.unl.edu/dissertations/AAI9013629