Sensitivity of oilseed rape (Brassica napus L.) to soil residues of imazethapyr herbicide

Abstract

Imazethapyr is one of imidazolinone herbicides that may leave residual activity in the soil for extended periods causinginjury and yield reduction of susceptible crops in rotation. An experiment was conducted in order to study the sensitivityof oilseed rape (Brassica napus L.) to imazethapyr soil residues. Experimental type was completely randomized designwith three replications. Treatments included Imazethapyr simulated concentrations residuals in soil (0.002, 0.004, 0.008,-1 0.012, 0.02 and 0.04 mg. kg soil). Shoot and root biomass production was measured 30 days after emergence. Oilseedrape responses to imazethapyr residues was fitted with sigmoidal 3 and 4 parametric equations to the root and shootbiomass data as a function of the herbicide residue concentrations and was used to calculate the doses for 50% inhibitionof root and shoot growth (ED ). Results showed that the oilseed rape shoot and root dry matter were significantly affected 50by increasing imazethapyr soil residue (p