Publications - Faculty - Recently Submitted Faculty Publications 2010
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Singh - Weed Technology
Leaching of Indaziflam in Various Horizons Compared to Residual Herbicides Commonly Used in Florida Citrus
Amit J. Jhala, Analiza H.M. Ramirez and Megh Singh
Abstract. Soil-applied herbicides are commonly used for a broad spectrum, residual weed control in Florida citrus. Groundwater contamination of some soil-applied herbicides has been reported in citrus growing areas in Florida. Indaziflam {N-[(1R, 2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1RS)-1fluoroethyl]-1,3,5-triazine-2,4-diamine} is a new soil-applied herbicide recently registered for a broad spectrum weed control in Florida citrus. There is no information available on leaching behavior of indaziflam in sandy soil. Experiments were conducted to compare leaching of indaziflam with five commercially applied, residual herbicides in Florida Candler soil under simulated rainfall of 5 and 15 cm ha-1. Herbicide movement down the soil columns was measured by evaluating visible injury and biomass of bioassay species ryegrass (Lolium perenne L.) seeded into the soil columns split longitudinally. Leaching of indaziflam increased with increasing amount of rainfall. For example, indaziflam leached up to 12.2 ± 0.8 cm and 27.2 ± 2.6 cm at 5 and 15 cm ha-1, respectively. Averaged across rainfall, herbicide ranking from high to low mobility was: bromacil > norflurazon > indaziflam > simazine > pendimethalin > diuron. Maximum mortality of ryegrass was observed in the 0 to 30 cm horizon ranging from 5 to 72% and 14 to 95%, respectively, at 5 and 15 cm ha-1. With indaziflam applied at a recommended rate of 73 g ai ha-1, there was no mortality of ryegrass beyond 30 cm and biomass was comparable with untreated control indicating that indaziflam would not leach beyond this distance even under 15 cm ha-1 rainfall in Florida Candler soil.
